THE NETWORKING INTERVIEW QUESTION AND ANSWER

THE NETWORKING INTERVIEW QUESTION AND ANSWER

What is backbone network?

A backbone network is a centralized infrastructure that is designed to distribute different routes and data to various networks. It also handles management of bandwidth and various channels.

What are routers?

Routers can connect two or more network segments. These are intelligent network devices that store information in its routing table such as paths, hops and bottlenecks. With this info, they are able to determine the best path for data transfer. Routers operate at the OSI Network Layer.

What is anonymous FTP?

Anonymous FTP is a way of granting user access to files in public servers. Users that are allowed access to data in these servers do not need to identify themselves, but instead log in as an anonymous guest.

What is the maximum length allowed for a UTP cable?

A single segment of UTP cable has an allowable length of 90 to 100 meters. This limitation can be overcome by using repeaters and switches.

Describe Network Topology

Network Topology refers to the layout of a computer network. It shows how devices and cables are physically laid out, as well as how they connect to one another.

Briefly describe NAT.

NAT is Network Address Translation. This is a protocol that provides a way for multiple computers on a common network to share single connection to the Internet.

How does a network topology affect your decision in setting up a network?

Network topology dictates what media you must use to interconnect devices. It also serves as basis on what materials, connector and terminations that is applicable for the setup.

What are different ways of securing a computer network?

There are several ways to do this. Install reliable and updated anti-virus program on all computers. Make sure firewalls are setup and configured properly. User authentication will also help a lot. All of these combined would make a highly secured network.

What is WAN?

WAN stands for Wide Area Network. It is an interconnection of computers and devices that are geographically dispersed. It connects networks that are located in different regions and countries.

How many layers are there under TCP/IP?

There are four layers: the Network Layer, Internet Layer, Transport Layer and Application Layer.

What is the function of the OSI Session Layer?

This layer provides the protocols and means for two devices on the network to communicate with each other by holding a session. This includes setting up the session, managing information exchange during the session, and tear-down process upon termination of the session.

What does 10Base-T mean?

The 10 refers to the data transfer rate, in this case is 10Mbps. The word Base refers to base band, as oppose to broad band. T means twisted pair, which is the cable used for that network.

What is NOS?

NOS, or Network Operating System, is specialized software whose main task is to provide network connectivity to a computer in order for it to be able to communicate with other computers and connected devices.

What is OSI and what role does it play in computer networks?

OSI (Open Systems Interconnect) serves as a reference model for data communication. It is made up of 7 layers, with each layer defining a particular aspect on how network devices connect and communicate with one another. One layer may deal with the physical media used, while another layer dictates how data is actually transmitted across the network.

What is the advantage of address sharing?

By using address translation instead of routing, address sharing provides an inherent security benefit. That’s because host PCs on the Internet can only see the public IP address of the external interface on the computer that provides address translation and not the private IP addresses on the internal network.

What is the equivalent layer or layers of the TCP/IP Application layer in terms of OSI reference model?

The TCP/IP Application layer actually has three counterparts on the OSI model: the Session layer, Presentation Layer and Application Layer.

What is the main purpose of OSPF?

OSPF, or Open Shortest Path First, is a link-state routing protocol that uses routing tables to determine the best possible path for data exchange.

Describe star topology

Star topology consists of a central hub that connects to nodes. This is one of the easiest to setup and maintain.

What is the disadvantage of a star topology?

One major disadvantage of star topology is that once the central hub or switch get damaged, the entire network becomes unusable.

Give some examples of private network addresses.

10.0.0.0 with a subnet mask of 255.0.0.0 172.16.0.0 with subnet mask of 255.240.0.0 192.168.0.0 with subnet mask of 255.255.0.0

What are the functions of a network administrator?

A network administrator has many responsibilities that can be summarize into 3 key functions: installation of a network, configuration of network settings, and maintenance/troubleshooting of networks.

What is Hybrid Network?

A hybrid network is a network setup that makes use of both client-server and peer-to-peer architecture.

What is the main job of the ARP?

The main task of ARP or Address Resolution Protocol is to map a known IP address to a MAC layer address.

How can you manage a network using a router?

Routers have built in console that lets you configure different settings, like security and data logging. You can assign restrictions to computers, such as what resources it is allowed access, or what particular time of the day they can browse the internet. You can even put restrictions on what websites are not viewable across the entire network.

What is the use of a default gateway?

Default gateways provide means for the local networks to connect to the external network. The default gateway for connecting to the external network is usually the address of the external router port.

What is the proper termination rate for UTP cables?

The proper termination for unshielded twisted pair network cable is 100 ohms.

What is the number of network IDs in a Class C network?

For a Class C network, the number of usable Network ID bits is 21. The number of possible network IDs is 2 raised to 21 or 2,097,152. The number of host IDs per network ID is 2 raised to 8 minus 2, or 254.

What common software problems can lead to network defects?

Software related problems can be any or a combination of the following: - client server problems - application conflicts - error in configuration - protocol mismatch - security issues - user policy and rights issues

What is Ping?

Ping is a utility program that allows you to check connectivity between network devices on the network. You can ping a device by using its IP address or device name, such as a computer name.

What is DNS?

DNS is Domain Name Server. The main function of this network service is to provide host names to TCP/IP address resolution.

What is the difference between a hub and a switch?

A hub acts as a multiport repeater. However, as more and more devices connect to it, it would not be able to efficiently manage the volume of traffic that passes through it. A switch provides a better alternative that can improve the performance especially when high traffic volume is expected across all ports.

What are the maximum networks and hosts in a class A, B and C network?

For Class A, there are 126 possible networks and 16,777,214 hosts For Class B, there are 16,384 possible networks and 65,534 hosts For Class C, there are 2,097,152 possible networks and 254 hosts

What protocols fall under the Application layer of the TCP/IP stack?

The following are the protocols under TCP/IP Application layer: FTP, TFTP, Telnet and SMTP.

What is ipconfig?

Ipconfig is a utility program that is commonly used to identify the addresses information of a computer on a network. It can show the physical address as well as the IP address.

What is client/server?

Client/server is a type of network wherein one or more computers act as servers. Servers provide a centralized repository of resources such as printers and files. Clients refers to workstation that access the server.

When you move the NIC cards from one PC to another PC, does the MAC address gets transferred as well?

Yes, that’s because MAC addresses are hard-wired into the NIC circuitry, not the PC. This also means that a PC can have a different MAC address when the NIC card was replace by another one.

In a network that contains two servers and twenty workstations, where is the best place to install an Anti-virus program?

An anti-virus program must be installed on all servers and workstations to ensure protection. That’s because individual users can access any workstation and introduce a computer virus when plugging in their removable hard drives or flash drives.

What are some drawbacks of implementing a ring topology?

In case one workstation on the network suffers a malfunction, it can bring down the entire network. Another drawback is that when there are adjustments and reconfigurations needed to be performed on a particular part of the network, the entire network has to be temporarily brought down as well.

What is SMTP?

SMTP is short for Simple Mail Transfer Protocol. This protocol deals with all Internal mail, and provides the necessary mail delivery services on the TCP/IP protocol stack.

What is the importance of Encryption on a network?

Encryption is the process of translating information into a code that is unreadable by the user. It is then translated back or decrypted back to its normal readable format using a secret key or password. Encryption help ensure that information that is intercepted halfway would remain unreadable because the user has to have the correct password or key for it.

Explain the importance of authentication.

Authentication is the process of verifying a user’s credentials before he can log into the network. It is normally performed using a username and password. This provides a secure means of limiting the access from unwanted intruders on the network.

What are the different technologies involved in establishing WAN links?

Analog connections – using conventional telephone lines; Digital connections –using digital-grade telephone lines; switched connections – using multiple sets of links between sender and receiver to move data.

When troubleshooting computer network problems, what common hardware-related problems can occur?

A large percentage of a network is made up of hardware. Problems in these areas can range from malfunctioning hard drives, broken NICs and even hardware startups. Incorrectly hardware configuration is also one of those culprits to look into.

How does dynamic host configuration protocol aid in network administration?

Instead of having to visit each client computer to configure a static IP address, the network administrator can apply dynamic host configuration protocol to create a pool of IP addresses known as scopes that can be dynamically assigned to clients.

What is sneakernet?

Sneakernet is believed to be the earliest form of networking wherein data is physically transported using removable media, such as disk, tapes.

What protocols fall under the TCP/IP Internet Layer?

There are 4 protocols that are being managed by this layer. These are ICMP, IGMP, IP and ARP.

What is one basic requirement for establishing VLANs?

A VLAN requires dedicated equipment on each end of the connection that allows messages entering the Internet to be encrypted, as well as for authenticating users.

What is RSA algorithm?

RSA is short for Rivest-Shamir-Adleman algorithm. It is the most commonly used public key encryption algorithm in use today.

What is the maximum segment length of a 100Base-FX network?

The maximum allowable length for a network segment using 100Base-FX is 412 meters. The maximum length for the entire network is 5 kilometers.

If you are a victim of Denial of Service (Dos) then what you do?

The function of a denial of service attack is to flood its target machine with too much traffic and prevents it from being accessible to any other requests or providing services.

To prevent DoS attacks firewall can be configured as a relay; in this approach the firewall responds on behalf of the internal host. During the attack, the firewall responds to the SYN sent by the attacker; since the ACK never arrives, the firewall terminates the connection. By Keeping protocols and Antivirus software up-to-date, we can prevent to be a victim of DoS. A regular scanning of the machine is also necessary in order to detect any “anomalous” behavior.

Comment on Data Encryption Standard (DES) weakness and strength.

The Data Encryption Standard (DES) is a symmetric key block cipher which takes 64-bit plaintext and 56-bit key as an input and produces 64-bit cipher text as output. The DES function is made up of P and S-boxes. P-boxes transpose bits and S-boxes substitute bits to generate a cipher.

Strength- The strength of DES lies on two facts:

The use of 56-bit keys: 56-bit key is used in encryption, there are 256 possible keys. A brute force attack on such number of keys is impractical. The nature of algorithm: Cryptanalyst can perform cryptanalysis by exploiting the characteristic of DES algorithm but no one has succeeded in finding out the weakness.

Weakness- Weakness has been found in the design of the cipher:

Two chosen input to an S-box can create the same output. The purpose of initial and final permutation is not clear.

What are Brute Force Attacks?

Brute forcing is a mechanism which is used by an attacker to break the encryption of data by applying a set of various key. Cryptanalyst has a set of number of keys and apply them one by one to the encryption algorithm until he get the right key.

How do you use RSA for both authentication and secrecy?

RSA is a public key encryption algorithm. The RSA algorithms are based on the mathematical part that it is easy to find and multiply large prime numbers together, but it is extremely difficult to factor their product.

For authentication: One can encrypt the hash (MD4/SHA) of the data with a private key. This is known as digital signature.

For Secrecy: Secrecy/confidentiality is achieved by encrypting the data with public key and decrypting with private key.

Can you differentiate among encoding, encryption and hashing?

Encoding: Basically encoding is used to protect the integrity of data as it crosses through communication network to keep its original message upon arriving. It is primarily an insecure function because it is easily reversible.

Encryption: Encryption is basically designed for confidentiality and data integrity and reversible only if you have the appropriate key.

Hashing: With hashing the operation is one-way i.e. non-reversible. It takes an input (or ‘message’) and returns a fixed-size string, which is called the hash value.

If you have to generate a hash function then what characteristics are needed in a secure hash function?

A secure hash function should have the following characteristics:

i. The output generated by a hash function should be of a fixed length.

ii. It should be very easy to find out a hash function for a given message.

iii. If a hash value is given of a message than it is almost impossible to get that message.

iv. The two different messages should not have the same hash value; it is against the hash function property.

What is digital signature? Differentiate between Physical and Digital Signature

A digital signature is an electronic analogue of a written signature; the digital signature can be used to provide assurance that the claimed signatory signed the information. Digital signature is used to detect the integrity of signed data. We can differentiate between physical and digital signature as:

i. Physical signature is just writing on paper but digital signature includes crucial parameters of identification.

ii. Physical signature can be coped but it is impossible to copy a digital signature.

iii. Physical signature does not give any privacy to content but digital signature enables encryption and thus privacy.

What is Authentication Header and how it provides the protection to IP header?

Basically Authentication Header protects IP header and provides the complete authenticity to the IP packets.

AH may work in two ways: transport mode and tunnel mode.

In tunnel mode; AH protects the IP header using two IP header layers inner and outer. Inner IP header is used to contain the source and destination addresses, and the outer IP header is used to contain the security gateway information.

Explain SSL Protocol. How does it protect internet users from various threats?

The SSL protocol (Secure Socket Layer protocol) was originally developed by Netscape, to ensure security of data transported and routed through HTTP, LDAP or POP3 application layer.

SSL uses TCP as a communication layer to provide a reliable end-to-end secure and authenticated connection; which helps internet users to protect from various threats. SSL Record protocol is used to ensure the data security and integrity.

What is PIX firewall security? How does it differ from a firewall?

PIX (Private Internet Exchange)

It is a popular IP firewall and NAT (Network Address Translation) appliance.

PIX firewall security is developed by Cisco Systems.

PIX firewall is used to protect your network with a stateful packet filtering firewall.

A firewall is a part of a computer system or network that is designed to block unauthorized access while permitting authorized communications.

What are Malware? Explain different types of Malware

Malware is a software program which is developed to destroy a computer system. These programs runs in victim’s computer without any information to the victim, i.e. victim do not know that someone hacked his system.

Different types of malware are: worm, Trojans Horse, Rootkits.

Worm: Worm is a computer program which makes its copy again and again in the victim’s computer. They damage the network by using a lot bandwidth.

Trojan Horses: Trojan horse consists of two parts, server and client. Server is an executable file which runs on victim’s computer and attacker may take the full control of the victim’s computer.

Rootkits: Rootkits are used to hide the malicious processes from active process

What are replay attacks? Give an example of replay attack

Replay attacks are the network attacks in which an attacker spies the conversation between the sender and receiver and takes the authenticated information e.g. sharing key and then contact to the receiver with that key. In Replay attack the attacker gives the proof of his identity and authenticity.

Example:

Suppose in the communication of two parties A and B; A is sharing his key to B to prove his identity but in the meanwhile Attacker C eavesdrop the conversation between them and keeps the information which are needed to prove his identity to B. Later C contacts to B and prove its authenticity.

If you have to ‘encrypt’ as well as ‘compress’ data during transmission then which would you do first and why?

Data should be transmitted over any communication network in such a way that the data integrity and authenticity should be maintained, for this first compress the data and then encrypt the data.

The reason behind it is; if you encrypt first you will have nothing but random data to work with, which will destroy any potential benefit from compression.

What is the goal of Information Security in an organization?

Mainly there are three Information security goals in an organization: Confidentiality, Integrity and Availability.

Confidentiality: Confidentiality means maintaining secrecy during transmission of information.

Integrity: Integrity means changes made in the stored information need to be done only by authorized entities and through authorized mechanism.

Availability: Information is useless if it is not available. Availability means information created and stored should be available to authorized entities.

What is Symmetric-Key cryptography and Asymmetric-Key cryptography?

Symmetric-Key Cryptography: Symmetric-key cryptography uses a single key for both encryption and decryption. Encryption and decryption algorithm are inverse of each other.

Example:

To create the ciphertext from the plaintext John uses an encryption algorithm and a key. To create the plaintext from ciphertext, Bob uses the decryption algorithm and the same key.

Asymmetric-Key cryptography: It is also called public key cryptography. In public key cryptography two keys: a private key and a public key is used. Encryption is done through the public key and decryption through private key. Receiver creates both the keys and is responsible for distributing its public key to the communication community.

Example:

The sender (say John) uses the public key to encrypt the plaintext into ciphertext and the receiver (say Bob) uses his private key to decrypt the ciphertext.

Explain the services provided by IP (Internet Protocol) - Addressing, Fragmentation, Packet timeouts and options

1. Addressing: For the purpose of delivering data-gram packets, IP needs to know about the address of the destination. By including the host addressing, this task is carried out by IP. As IP operates in an internet, its systems are designed to accept the addressing of devices which are unique.

2. Fragmenting: The datagram packets are sent to the data link layer for the purpose of transmission on the network. The physical network frame size that uses IP may be different. To resolve this, IP fragments the datagram into certain pieces. So that, each piece can be carried on the network. The receiving systems use these pieces and reassemble the whole IP datagram again.

3. Packet timeouts: A timeout packet is the time for waiting next instruction from the command station. If the command is not sent by the station, it shuts down.

Explain the classes of IP address

IP addresses are organized into classes. For convenience of humans, IP addresses are expressed in the decimal format. Every number in each class is represented as binary to computers.

The four numbers in an IP address are known as ‘octets’. Each of them has eight bit positions. The octets are divided into two sections: Net and Host. The first octet represents Net for identifying the network and the Host contains the last octet. There are five IP classes.

Class A: The class A is used for very large networks. There are 1 to 126 are part of this class. That means there are 126 Class A networks. Class A networks accounts for half of the total available IP addresses.

Class B: It is used for medium size networks. The IP address with a first octet from 128 to 191 is part of this class. Class B networks have a first bit value of 1 and a second bit value of 0 in the first octet.

Class C: Class C is used for small to middle size networks. IP address with a first octet starts from 192-223. Class C networks have a first bit value of 1, second bit value of 1 and a third bit value of 0 in the first octet.

Class D: It has first, second and third bit value as 1 and the fourth bit as 0. The other 28 bits are used for identifying the group of computers which is intended for multicast messages.

Class E: Class E is used for identification purpose. The four bits value is 1. The other 28 bits are used for identifying the group of computers which is intended for multicast messages.

Define Broadcast, Unicast and Multicast.

Unicast: A term used in communication to describe a piece of information to send from one point to another. There are only sender and receiver. All LANs support unicast transfer mode and most applications that employ TCP transport protocol uses unicast messaging.

Broadcast: A term used for describing communication that is sent a piece of information from one point to all other points. There is one sender and multiple receivers. All LANs support broadcast transmission.

Multicast: A term described in communicating a piece of information sent from one or more points to a set of other points. The senders and receivers are one or more.

What is Network Mask?

A network mask is used for determination of what subnet an IP address belongs to. An IP address has network address and the host address. The first two numbers represents the network address and the second two numbers represents the host of the network.

Define Subnetting.

A subnet describes a set of networked computers which have common IP address routing prefix.

Breaking the networking into smaller and more efficient subnets is known as subnets. Subnetting prevents Ethernet packet collision which has excessive rates in a large network. Routers are used to manage the traffic and constitute borders among subnets.

What is the User Datagram Protocol (UDP)?

User datagram protocol allows computer applications to send messages as datagram packets from source to destination on an Internet Protocol, with out using prior communications for setting up special transmission paths. An unreliable service is provided by UDP which makes the datagram packets may arrive irrespective of order. UDP is a better solution for time-sensitive applications due to the reason ‘dropping packets is preferable to use delayed packets’. Its stateless nature makes the server to answer smaller queries to huge number of clients.

Explain TCP Windowing concept.

TCP Windowing is a concept that is used for avoiding congestion in the network traffic. Unacknowledged amount of data that is sent by the sender before the data gets acknowledgment back from the receiver that it has received it is controlled.

What is the Domain Name System (DNS)? What are the advantages of it?

A hierarchical naming system for computer systems, services or for that matter any resource participating in the internet. Various information with domain names is assigned to each of the participants. DNS translates the names of domain into meaningful to humans into binary identifiers that are associated with the equipment of network to locate and address these devices.

Advantages:

More Reliable: Delivers messages to the users with zero downtime.

Faster: DNS are connected well at intersections of internet. Any cast technology enables requests are answered to the next closest node in the case of maintenance or downtime.

Smarter: Automatic corrections of typos.

What is the TTL (Time to Live)? Why is it required?

TTL is a value in data packet of Internet Protocol. It communicates to the network router whether or not the packet should be in the network for too long or discarded. Usually, data packets might not be transmitted to their intended destination within a stipulated period of time. The TTL value is set by a system default value which is an 8-bit binary digit field in the header of the packet. The purpose of TTL is, it would specify certain time limit in seconds, for transmitting the packet header. When the time is exhausted, the packet would be discarded. Each router receives the subtracts count, when the packet is discarded, and when it becomes zero, the router detects the discarded packets and sends a message, Internet Control Message Protocol message back to the originating host.

Explain the use of Internet Control Message Protocol (ICMP).

Internet Control Message Protocol is one of the important protocols in the Internet Protocol suite. It is mainly used in operating system of networked computers, for the purpose of sending error messages, for example, a requested service is unavailable or the host could not be reached. It is not directed by the network applications. ICMPs are utilized by routers, hosts for communicating the updates or error information to other routers.

What is the use of IGMP protocol?

Internet Group Management Protocol: - It allows internet hosts to participate in multicasting. The IGMP messages are used to learn which hosts is part of which multicast groups. The mechanism also allow a host to inform its local router, that it wants to receive messages.

What are Ping and Tracert?

Ping and tracert are the commands used to send information to some remote computers to receive some information. Information is sent and received by packets. Ping I particularly used to check if the system is in network or not. It also gives packet lost information. In windows ping command is written as ping ip_address Tracert is called as trace route. It is used to track or trace the path the packet takes from the computer where the command is given until the destination. In windows ping command is written as tracert ip_address

Explain RSVP. How does it work?

Resource Reservation protocol is used to reserve resources across a network. It is used for requesting a specific Quality of Service (QoS) from the network. This is done by carrying the request (that needs a reservation of the resource) of the host throughout the network. It visits each node in the network. RSVP used two local modules for reservation of resources. Admission control module confirms if there are sufficient available resources while policy module checks for the permission of making a reservation. RSVP offers scalability. On a successful completion of both checks RSVP uses the packet classifier and packet scheduler for the desired Qos requested.

Explain the concept of DHCP.

Dynamic Host Configuration Protocol is used assigning IP addresses to computers in a network. The IP addresses are assigned dynamically. Certainly, using DHCP, the computer will have a different IP address every time it is connected to the network. In some cases the IP address may change even when the computer is in network. This means that DHCP leases out the IP address to the computer for sometime. Clear advantage of DHCP is that the software can be used to manage IP address rather than the administrator.

What are the differences between a domain and a workgroup?

In a domain, one or more computer can be a server to manage the network. On the other hand in a workgroup all computers are peers having no control on each other. In a domain, user doesn’t need an account to logon on a specific computer if an account is available on the domain. In a work group user needs to have an account for every computer. In a domain, Computers can be on different local networks. In a work group all computers needs to be a part of the same local network.

Explain how NAT works.

Network Address Translation translates and IP address used in a network to another IP address known within another network. A NAT table is maintained for global to local and local to mapping of IP’s. NAT can be statically defined or dynamically translate from a pool of addresses. The NAT router is responsible for translating traffic coming and leaving the network. NAT prevents malicious activity initiated by outside hosts from reaching local hosts by being dependent on a machine on the local network to initiate any connection to hosts on the other side of the router.

What is PPP protocol? Explain PPP packet format.

Point to Point protocol helps communication between 2 computers over a serial cable, phone line or other fiber optic lines. E.g. Connection between an Internet Service Provider and a host. PPP also provides authentication. PPP operates by sending Request packets and waiting for Acknowledge packets that accept, reject or try to change the request. The protocol is also used to negotiate on network address or compression options between the nodes.

Packet format:-

Flag field: 1 byte: - Indicates frames beginning or end Address field: 1 byte: - Used for broadcast address (destination address) Control field: 1 byte: - Used as a control byte Protocol field: - 1 or 2 bytes: - Setting of protocol in information field (of datagram) Information: - 0 or more bytes: - Datagram (whether it contains data or control information) Padding: - 0 or more bytes: - optional padding FCS: - 2 or more bytes: - error check sum

What is IP Spoofing and how can it be prevented?

IP spoofing is a mechanism used by attackers to gain unauthorized access to a system. Here, the intruder sends messages to a computer with an IP address indicating that the message is coming from a trusted host. This is done by forging the header so it contains a different address and make it appear that the packet was sent by a different machine.

Prevention:-Packet filtering: - to allow packets with recognized formats to enter the network Using special routers and firewalls. Encrypting the session

What is an application gateway?

An application gateway is an application program that runs on a firewall between two networks. An application gateway is used for establishing connection between client program and destination service. The client negotiates with the gateway to communicate with the service of destination. Here, gateway can be called as a proxy. Hence, two connections are made. One between client and proxy; other, between proxy and destination service. Connections take place behind the firewall

What is 'Gateway Of Last Resort'?

A Gateway of Last Resort or Default gateway is a route used by the router when no other known route exists to transmit the IP packet. Known routes are present in the routing table. Hence, any route not known by the routing table is forwarded to the default route. Each router which receives this packet will treat the packet the same way, if the route is known, packet will be forwarded to the known route.

What is Router? Explain components of Routers.

The way switches connect multiple computers, a router connects multiple networks. Routers comprise of data consisting of large tables of networks and addresses. Routers use algorithms to determine the shortest route to an address in a network.

Explain different layers in the OSI model.

Application Layer:

Closest to the end user Interact directly with the software application.

Presentation Layer:

Translates application to network format, and vice versa Works to transform data into the form that the application layer can accept Formats and encrypts data to be sent across a network

Session Layer

Controls the connections between computers Establishes, manages and terminates the connections between the local and remote application. Provides full-duplex, half-duplex, or simplex operation Establishes checkpointing, adjournment, termination, and restart procedures

Transport Layer:

Provides transparent transfer of data between end users Providing reliable data transfer services to the upper layers Controls the reliability of a given link through flow control, segmentation /desegmentation, and error control.

Network Layer

Provides the functional and procedural means of transferring variable length data sequences from a source to a destination via one or more networks Performs networkrouting functions Performs fragmentation and reassembly, and report delivery errors.

Data Link Layer

Provides the functional and procedural means to transfer data between network entities Detects and corrects errors that occur in the Physical Layer.

Physical Layer:

Defines the electrical and physical specifications for devices.

What is IP Multicasting?

It is an IP address that identifies a particular group of hosts in network. This group of hosts is called a multicast group.

What is Subneting? Explain the advantages of using Subneting.

Subneting is dividing a network into several subnets. This is usually done for the following purposes:

Reducing network traffic by decreasing the number of broadcasts Exceeding the limitations in a local area network Enabling people to connect to the network remotely without opening the entire network

What is VLSM, Variable length subnet masking?

VLSM is a means of allocating IP addressing resources to subnets according to their individual need rather than some general network-wide rule.

Explain the concepts and capabilities of IP Datagram.

Data transmitted over an internet using IP is carried in messages called IP datagrams. Like all network protocol messages, IP uses a specific format for its datagrams.

The IPv4 consists of the following fields:

Version: the version of IP used to generate the datagram. For IPv4, this is of course the number 4 Internet Header Length: Specifies the length of the IP header, in 32-bit words. Type of service: information to provide quality of service features Total Length Identification: it can be used if the datagram must be fragmented by a router during delivery and then for reassembling. Flags: (Don’t Fragment, More Fragment) Fragment Offset: When fragmentation of a message occurs, this field specifies the offset, or position. Time to Live: specifies how long the datagram is allowed to “live” Protocol: ICMP, TCP, UDP, etc Header Checksum: to provide basic protection against corruption in transmission. Source Address Destination Address Options Padding: if number of bits used for options is not a multiple of 32, then paddin is added Data

What is MAC address?

Media Access Control address is an identifier for assigned to most network adapters or Network Interface Cards by the manufacturer for the purpose of identification. MAC address is used in MAC protocol sub layer. MAC address is usually encodes the registered identification number that is registered by the manufacturer. The numbering spaces managed by the IEEE, which are common for formulating a MAC address: MAC-48, EUI-48 and EUI-64.

Explain the function of Transmission Control Block

Hort for trusted computing base. TCB refers to the totality of protection mechanisms (hardware, firmware and software) that provide a secure computing environment. The TCB includes everything that must be trusted --access control, authorization and authentication procedures, cryptography,firewalls, virus protection, data backup, and even human administration -- in order for the right level of security to work.

Difference between bit rate and baud rate?

Bit rate is no. of bits transmitted during one second. baud rate is max. no of times the signal is change per second.

What is the difference between tree and forest?

A tree start whenever you install the first domain controller and a tree may consist a single domain or multiple domain arranged in structure called child or grand child which will inherit name from its parent. When we install first domain controller a new domain ,anew tree and a new forest begins.In a new forest you can have single tree or multiple tree.

What is NETBIOS and NETBEUI?

NETBIOS: basic input and output system.It is a non-routable protocol. NETBEUI:Netbeui is the protocol that is is responsible for data transport.does handle all the frame formatting that is not handled by netbios.

What is RIP (Routing Information Protocol)?

Rip (routing information protocol) their are two type .class full and classless protocol.is a distance vector protocol selecting nearest best path count a hope 0 to 15.

What is the difference between TFTP and FTP application layer protocols?

FTP is connection oriented, where as TFTP is not. TFTP uses error checking and flow control, where as TFTP does not cause error checking.

FTP uses TCP as transport protocol, where as TFTP uses UDP as transport protocol. Authentication is mandatory in FTP, where as authentication is not needed in TFTP.

Just getting and putting application effectively is the design concern of TFTP, where as FTP provides more control and data connection aspects.

how drivers are selected and implemented for various network components.

Drivers are selected for Network components as per their performance and capacity to carry the signals accross the network and it also depends on the performance of the drivers of Networks selected, that should be robust and easy to implement and secure.

Difference between the communication and transmission?

Transmission can be looked into as an issue of lower layers like physical layer, while communication is an activity about which user is concerned and is related with application layer activity. transmission looks at the actual techniques used for data transfer whereas communication looks at user aspects and deals with whole messages instead of raw bits.

What are 10Base2, 10Base5 and 10BaseT Ethernet LANs ?
10Base5: means transmission speed 10 Mbps, coaxial cable, maximum segment length 500 metre, network length 2500 metre, minimum distance between node 2.5 metre. 10Base2: means transmission speed 10 Mbps, coaxial cable, maximum segment length 185 metre, network length 925 metre, minimum distance between node 0.5 metre 10BaseT: means transmission speed 10 Mbps, UTP(unshielded twisted pair)cat 3,4,5, maximum segment length 100 metre, network length 500 metre

How can we create VPN to connect to branch office of the same office.what would be the priliminary requirment? First of all what is VPN." VPN " stand for Virtual Private Network .Next how it works and where it is used . VPN works when the IP Conficts and IP is conflict because we dont use the PUBLIC IP means the IP we use is may be used by onther Company or Branch then we use VPN it works in the MAC address principal means it doesnot work on the IP it works Over the IP . And COMPUTER ,INTERNET or INTRANET, DHCP is required for the VPN .

What is difference between baseband and broadband transmission?

In a base-band transmission, the entire bandwidth of the cable is consumed by a single signal. In broadband transmission, signals are sent on multiple frequencies, allowing multiple signals to be sent simultaneously.

What is piggy backing?

The technique of temporarily delaying outgoing acknowledgement so that it can hooked on to the next outgoing data frames is called piggybacking.. the advantage of using piggybacking is the better utilization of available channel bandwidth..

What are Digrams and Trigrams?

The most common two letter combinations are called as diagrams. e.g. th, in, er, re and an. The most common three letter combinations are called as trigrams. e.g. the, ing, and, and ion.

What is frame relay, in which layer it comes?

FRAME RELAY is packet-switching protocol for connecting devices on a Wide Area Network (WAN). Frame Relay networks in the U.S. support data transfer rates at T-1 (1.544 Mbps) and T-3 (45 Mbps) speeds. In fact, you can think of Frame Relay as a way of utilizing existing T-1 and T-3 lines owned by a service provider. Most telephone companies now provide Frame Relay service for customers who want connections at 56 Kbps to T-1 speeds. (In Europe, Frame Relay speeds vary from 64 Kbps to 2 Mbps. it operats at datalink layer os osi model

What is region?

When hierarchical routing is used, the routers are divided into what we call regions, with each router knowing all the details about how to route packets to destinations within its own region, but knowing nothing about the internal structure of other regions.

when hierarchical routing is used,the routers are divided into what we call regions,with each router knowing all the details about how to route packets to destinations within its own region,but knowing nothing about the internal structure of other regions.

What is SLIP (Serial Line Interface Protocol)?

It is a very simple protocol used for transmission of IP datagrams across a serial line.

What is terminal emulation, in which layer it comes?

Telnet is also called as terminal emulation. It belongs to application layer.

What is BGP (Border Gateway Protocol)?

It is a protocol used to advertise the set of networks that can be reached with in an autonomous system. BGP enables this information to be shared with the autonomous system. This is newer than EGP (Exterior Gateway Protocol).

What is NVT (Network Virtual Terminal)?

It is a set of rules defining a very simple virtual terminal interaction. The NVT is used in the start of a Telnet session.

What is IGP (Interior Gateway Protocol)?

In contrast an Exterior Gateway Protocol (EGP) is for determining network reachability between autonomous systems and makes use of IGPs to resolve routes within an AS.

What is virtual path?

Along any transmission path from a given source to a given destination, a group of virtual circuits can be grouped together into what is called path.

What is the difference between physical address and logical address?

Simply physical address known as hardware address.IP address is known as logical address.Physical address is used for identify the PC on network and IP is used for identify the network on the PC mac address 48 bit address IP address 32 bit address.

Describe a 3-way TCP/IP Handshake.

(1) first time check that destination port is present on network yes or no (2) second time check that port is on or off and it receive request on port. (3) send message of destination side that sender side is ready for connection.

What are the difference between node,host,terminal,system,hub?

These are all different things in networking. Hub:Where we connect all the the links for a networking connection. Node:It can be identified as a one connection. Host:is nothing than if you are going to send a request to the server the questioned system can be know as a host.

WHAT IS DIFFERENCE BETWEEN DIAL-UP INTERNET CONNECTION AND BROADBAND CONNECTION?

Dial up connection is just like telephone ,anyone wants to talk to someone have to dial a number talk to the person and disconnect the phone, it also requires a username/password & a modem to connect to internet.The speed of net is variable and sometimes its upto 56kbps . In this either the phone or the internet will work at a time. We can't use both simultaneously internet and phone. While in broadband connection , its also requires a modem & may need user/password.It is directly connected with LAN card and/or by wireless also can be adopted for the same. In this we can simultaneously work on internet and on phone.Its speed ranges from 256kbps to several mbps.

What is a difference between switch and Hub?

hub:Each port of hub is collision domain&broadcast domain switch:each port of switch is collision domain & each vlan is broadcast domain

1.explain 7 osi layers briefly. 2.define router,gateways,brouter. 3.explain abt encryption & decryption.

OSI layers are same as the above. Routers are devices which routes packets from source to destination. Gateways are the entry ports or the entry gates through which packets enter. Encryption is a process of converting plain text to cipher(encoded) text. Decryption is cipher to plain.

What is difference between ARP and RARP?

The address resolution protocol (ARP) is used to associate the 32 bit IP address with the 48 bit physical address, used by a host or a router to find the physical address of another host on its network by sending a ARP query packet that includes the IP address of the receiver.

The reverse address resolution protocol (RARP) allows a host to discover its Internet address when it knows only its physical address.

ARP-Address resulution protocol Used to find the physical address if it knows the logical address.

RARP-Reverse address resolution protocol Used to find the logical address if it knows the physical address.

What do you meant by "triple X" in Networks?

The function of PAD (Packet Assembler Disassembler) is described in a document known as X.3. The standard protocol has been defined between the terminal and the PAD, called X.28; another standard protocol exists between hte PAD and the network, called X.29. Together, these three recommendations are often called "triple X".

What are the possible ways of data exchange?

(i) Simplex

(ii) Half-duplex

(iii) Full-duplex.

Why should we care about the OSI Reference Model ? What is the main purpose for creating this osi model? why it is a layered model?

The main aim to design the OSI model is that actully they want to set a standerd for the communication and want to standarized the network equipement so that they would not be any Brand consuines

ISO stands International Standards Organization established 1940's and ISO developed OSI means Open System Interconnection model for communication at 1970's. It is a layerd model. Advantages of layered model is 1.complexity can be reduced. 2. Modifications can be achieved without affecting higher and lower layers.

What is Protocol Data Unit?

The data unit in the LLC level is called the protocol data unit (PDU). The PDU contains of four fields a destination service access point (DSAP), a source service access point (SSAP), a control field and an information field. DSAP, SSAP are addresses used by the LLC to identify the protocol stacks on the receiving and sending machines that are generating and using the data. The control field specifies whether the PDU frame is a information frame (I - frame) or a supervisory frame (S - frame) or a unnumbered frame (U - frame).

What is a Multi-homed Host?

It is a host that has a multiple network interfaces and that requires multiple IP addresses is called as a Multi-homed Host.

The host has multiple interfaces and each interface has one, or more, IP addresses. If one of the links fails, then its IP address becomes unreachable, but the other IP addresses will still work.

What is a Management Information Base (MIB)

A Management Information Base is part of every SNMP-managed device. Each SNMP agent has the MIB database that contains information about the device's status, its performance, connections, and configuration. The MIB is queried by SNMP.

Why should you care about the OSI Reference Model?

OSI model is a reference model that explains how a network device should behave in its position(layer). and also explains how the data will move in the network at different layers this helps to easily locate the troubles in network to over come the problem and also gives a standard for the devices with which the different vendors can inter operate.

What is attenuation?

Attenuation means signal loose some of its energy during transmission. so we need to amplify the signal before it becomes very weak.

What is the HELLO protocol used for?

The HELLO protocol uses time instead of distance to determine optimal routing. It is an alternative to the Routing Information Protocol.

What is redirector?

Redirector is software that intercepts file or prints I/O requests and translates them into network requests. This comes under presentation layer.

The two types of transmission technology available are Analog and the Digital technology.

Whatz the difference between DNS and WINS?

DIFFRENTS BETWEEN DNS AND WINS. DNS STANDS FOR DOMAIN NAMING SERVICE WHICH IS USED TO RESOLVE THE IP ADDRESS TO NAME & NAME TO IP ADDRESS. WINS STANDS FOR WINDOWS INTER NETWORK SERVICES. WHICH IS USED TO CONVERT NETBIOS NAME TO IP ADDRESS. WINS WORKS ONLY IN WINDOWS ENVIORNMENT.

What is subnetting?Why is it used?

A portion of a network that shares a common address component. On TCP/IP networks, subnets are defined as all devices whose IP Address have the same prefix.

What is the range of addresses in the classes of internet addresses?

class A 0.0.0.0 126.255.255.255 class B 128.0.0.0 191.255.255.255 class c 192.0.0.0 223.255.255.255 class D 224.0.0.0 239.255.255.255 class E 240.0.0.0 255.255.255.255

What is Kerberos?

It is an authentication service developed at the Massachusetts Institute of Technology. Kerberos uses encryption to prevent intruders from discovering passwords and gaining unauthorized access to files.

kerberos is a network authentication protocol which utilize symmetric cryptography to provide authentication for client server application.

What are the two types of transmission technology available?

(i) Broadcast

(ii) point-to-point.

What is the difference between collision domain and broadcast domain

Broadcast Domain: A set of all devices that recieve broadcast frames originating from any device within the set. Broadcast domains are typically bounded by routers (or, in a switched network, by VLANs) because routers do not forward broadcast frames.

Collision Domain: In Ethernet, the network area within which frames that have collided are propagated. Repeaters and Hubs prpagate collisions, LAN switches and bridges do not.

What is point-to-point protocol?

A communications protocol used to connect computers to remote networking services including Internet service providers.

1) Industry standard protocol 2) used to create point-to-point links between different vendors equipment

If a person is accessing his corporate network from home, how is the connection established and how does the data flow from internet to intra net?

If u want to access ur corporate network from ur public network(internet) u have to use VPN. It carries the data in a secured mode in public network. For this u need to install VPN software n u need some authentication for that from u r company. Now a days u can access ur internal site from normal internet.It is with this kind of secured con nection only. If u want to know more abt this, search regarding VPN in Google u can finds tonns of data.

What is the Network Time Protocol

NTP (Network Time Protocol) provides accurate and syncronised time across the Internet.NTP uses UDP port 123 as its transport layer. NTP is one of the oldest Internet protocols still in use NTP uses Marzullo's algorithm with the UTC time scale

What is autonomous system?

It is a collection of routers under the control of a single administrative authority and that uses a common Interior Gateway Protocol.

Autonomous System is a community of interest. Used in conjunction with Routing Protocols. It breaks up parts of the network into manageable chunks. It is a collection of Routers under the control of a single administrative authority and that use a common IGP.

What is cladding?

A layer of a glass surrounding the center fiber of glass inside a fiber-optic cable.

What is packet filter?

Packet filter is a standard router equipped with some extra functionality. The extra functionality allows every incoming or outgoing packet to be inspected. Packets meeting some criterion are forwarded normally. Those that fail the test are dropped.

On the Internet, packet filtering is the process of passing or blocking packets at a network interface based on source and destination addresses, ports, or protocols. The process is used in conjunction with packet mangling and Network Address Translation (NAT). Packet filtering is often part of a firewall program for protecting a local network from unwanted intrusion.

What is MAU?

A multistation access unit (MSAU) is a hub or concentrator that connects a group of computers ("nodes" in network terminology) to a Token Ring local area network.

What are the possible ways of data exchange?

(i) Simplex (ii) Half-duplex (iii) Full-duplex.

What is MTU of a link ?

Maximum Transmission Unit is the largest physical packet size, measured in bytes, that a network can transmit. Any messages larger than the MTU are divided into smaller packets before being sent. Every network has a different MTU, which is set by the network administrator. On Windows 95, you can also set the MTU of your machine. This defines the maximum size of the packets sent from your computer onto the network. Ideally, you want the MTU to be the same as the smallest MTU of all the networks between your machine and a message's final destination. Otherwise, if your messages are larger than one of the intervening MTUs, they will get broken up (fragmented), which slows down transmission speeds.

Trial and error is the only sure way of finding the optimal MTU, but there are some guidelines that can help. For example, the MTU of many PPP connections is 576, so if you connect to the Internet via PPP, you might want to set your machine's MTU to 576 too. Most Ethernet networks, on the other hand, have an MTU of 1500, which is the default MTU setting for Windows 95.

What are the types of Transmission media?

Signals are usually transmitted over some transmission media that are broadly classified in to two categories:-

Guided Media: These are those that provide a conduit from one device to another that include twisted-pair, coaxial cable and fiber-optic cable. A signal traveling along any of these media is directed and is contained by the physical limits of the medium. Twisted-pair and coaxial cable use metallic that accept and transport signals in the form of electrical current. Optical fiber is a glass or plastic cable that accepts and transports signals in the form of light.

Unguided Media: This is the wireless media that transport electromagnetic waves without using a physical conductor. Signals are broadcast either through air. This is done through radio communication, satellite communication and cellular telephony.

What is ERD(Emergency Repair Disk)?

Emergency Repair Disk, an ERD is a diskette that creates backups of important system files and settings and is used to help troubleshootand fix issues for Microsoft WINNT and WIN 2000. The ERD is used in conjunction with the Windows repair option and you will be prompted for the diskette when needed. Note: The ERD is not to be confused with a standard boot diskette as it cannot be used alone.

The ERD is capable of performing such checks as:

1. Verifying the boot sector is not corrupt.

2. Repairing any startup files.

3. Locate any missing or damaged system files.

how install ca certificate in win 2k3 & win 2k8? pls explain me this question???

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What is logical link control?

One of two sublayers of the data link layer of OSI reference model, as defined by the IEEE 802 standard. This sublayer is responsible for maintaining the link between computers when they are sending data across the physical network connection.

The Logical Link Control (LLC) data communication protocol layer is the upper sub-layer of the Data Link Layer (which is itself layer 2, just above the Physical Layer) in the seven-layer OSI reference model. It provides multiplexing and flow control mechanisms that make it possible for several network protocols (IP, IPX) to coexist within a multipoint network and to be transported over the same network media.

What do you meant by "triple X" in Networks?

The function of PAD (Packet Assembler Disassembler) is described in a document known as X.3. The standard protocol has been defined between the terminal and the PAD, called X.28; another standard protocol exists between the PAD and the network, called X.29. Together, these three recommendations are often called "triple X".

What is RIP (Routing Information Protocol)?

It is a simple protocol used to exchange information between the routers.

What is Mail Gateway?

It is just like gateway which is used to connect two different networks following different protocols. Mail gateway manages mail transfer between two networks using different mail transfer protocols.

What is Load balancing?

If the number of incoming clients requests exceeds the number of processes in a server class, the TP Monitor may dynamically start new ones and this is called Load balancing.

What is the difference between an unspecified passive open and a fully specified passive open?

An unspecified passive open has the server waiting for a connection request from a client. A fully specified passive open has the server waiting for a connection from a specific client.

What is the difference between TFTP and FTP application layer protocols?

The Trivial File Transfer Protocol (TFTP) allows a local host to obtain files from a remote host but does not provide reliability or security. It uses the fundamental packet delivery services offered by UDP. The File Transfer Protocol (FTP) is the standard mechanism provided by TCP / IP for copying a file from one host to another. It uses the services offered by TCP and so is reliable and secure. It establishes two connections (virtual circuits) between the hosts, one for data transfer and another for control information.

What is REX?

Request to Exit (REX) - A signal that informs the controller that someone has requested to exit from a secure area.

What is the range of IP addresses in the classes of internet addresses?

range of IP addresses in the classes of internet addresses are as under...

Class A 0.0.0.0 - 127.255.255.255 Class B 128.0.0.0 - 191.255.255.255 Class C 192.0.0.0 - 223.255.255.255 Class D 224.0.0.0 - 239.255.255.255 Class E 240.0.0.0 - 247.255.255.255

What are the possible ways of data exchange?

(i) Simplex (ii) Half-duplex (iii) Full-duplex.

What is BGP (Border Gateway Protocol)?

What is Recovery Console?

Recovery Console:That helps you restore your operating system when you cannot start your system.

What is ICMP?

ICMP is Internet Control Message Protocol, a network layer protocol of the TCP/IP suite used by hosts and gateways to send notification of datagram problems back to the sender. It uses the echo test / reply to test whether a destination is reachable and responding. It also handles both control and error messages.

What is meant by Horizontal scaling and Vertical scaling?

Horizontal scaling means adding or removing client workstations with only a slight performance impact. Vertical scaling means migrating to a larger and faster server machine or multiservers.

What is a DNS resource record?

A resource record is an entry in a name server's database. There are several types of resource records used, including name-to-address resolution information. Resource records are maintained as ASCII files.

it is a record entry table in which there is mapping of host name to ip,c-name to host name..

What is Beaconing?

The process that allows a network to self-repair networks problems. The stations on the network notify the other stations on the ring when they are not receiving the transmissions. Beaconing is used in Token ring and FDDI networks.

What is the difference between routable and non - routable protocols?

Routable protocols can work with a router and can be used to build large networks. Non-Routable protocols are designed to work on small, local networks and cannot be used with a router.

What is virtual channel?

Virtual channel is normally a connection from one source to one destination, although multicast connections are also permitted. The other name for virtual channel is virtual circuit.

What is logical link control?

What are called Non-GUI clients, GUI Clients and OOUI Clients?

Non-GUI Client: These are applications, generate server requests with a minimal amount of human interaction. GUI Clients: These are applications, where occasional requests to the server result from a human interacting with a GUI (Example: Windows 3.x, NT 3.5) OOUI clients : These are applications, which are highly-iconic, object-oriented user interface that provides seamless access to information in very visual formats. (Example: MAC OS, Windows 95, NT 4.0)

What is point-to-point protocol?

A communications protocol used to connect computers to remote networking services including Internet service providers.

What is redirector in Networking?

Redirector is software that intercepts file or prints I/O requests and translates them into network requests. This comes under presentation layer.

Why should you care about the OSI Reference Model?

It provides a framework for discussing network operations and design.

How we save ip addresses through subnetting how to avoid the wasting of assigning ip addresses by subnetting?

By Subnetting technique we can save wastage of Ip addresses. Subnetting is a process of creating a sub network from a bigger network. First we have to decide how many ip's does we need then we have to apply subnetting technique to find which network class is suitable for this much of IP's.

What is the Network Time Protocol?

A protocol that assures accurate local timekeeping with reference to radio and atomic clocks located on the Internet. This protocol is capable of synchronizing distributed clocks within milliseconds over long time periods. It is defined in STD 12, RFC 1119.

What is deffrence between switch & hub

Hub is a physical layer device which is a multiport repeater also.It regenerates the signals and broadcast the signals to those devices which are connected to the hub

where as

Switch is data link layer device which provide bridging functionality with greater efficiency.a switch may act as a multiport bridge to connect devices or segments in a LAN

What is Mail Gateway?

It is a system that performs a protocol translation between different electronic mail delivery protocols.

Difference between the communication and transmission?

Transmission is a physical movement of information and concern issues like bit polarity, synchronization, clock etc. Communication means the meaning full exchange of information between two communication media.

Why Data Link Layer Protocol Programming is preferable in C?

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What is source route?

It is a sequence of IP addresses identifying the route a datagram must follow. A source route may optionally be included in an IP datagram header.

What are the different type of networking / internetworking devices?

Repeater: Also called a regenerator, it is an electronic device that operates only at physical layer. It receives the signal in the network before it becomes weak, regenerates the original bit pattern and puts the refreshed copy back in to the link. Bridges: These operate both in the physical and data link layers of LANs of same type. They divide a larger network in to smaller segments. They contain logic that allow them to keep the traffic for each segment separate and thus are repeaters that relay a frame only the side of the segment containing the intended recipient and control congestion. Routers: They relay packets among multiple interconnected networks (i.e. LANs of different type). They operate in the physical, data link and network layers. They contain software that enable them to determine which of the several possible paths is the best for a particular transmission. Gateways: They relay packets among networks that have different protocols (e.g. between a LAN and a WAN). They accept a packet formatted for one protocol and convert it to a packet formatted for another protocol before forwarding it. They operate in all seven layers of the OSI model.

What is a pseudo tty?

A pseudo tty or false terminal enables external machines to connect through Telnet or rlogin. Without a pseudo tty, no connection can take place.

what is drive manager?

Firstly its a DriverManager class which is reside in java.sql.DriverManager package and used to call its static function getConnection()which have Connection string,user name, and password of the database.It use to be connect your program code with database.

What are the main components of Transaction-based Systems?

Resource Manager Transaction Manager and Application Program.

What are the most typical functional units of the Client/Server applications?

User interface Business Logic and Shared data.

What is the difference between routable and non - routable protocols?

Routable protocols can work with a router and can be used to build large networks. Non-Routable protocols are designed to work on small, local networks and cannot be used with a router.

What is attenuation?

The degeneration of a signal over distance on a network cable is called attenuation.

What is meant by Asymmetric Multiprocessing (AMP)?

It imposes hierarchy and a division of labor among processors. Only one designated processor, the master, controls (in a tightly coupled arrangement) slave processors dedicated to specific functions.

What does the Mount protocol do?

The Mount protocol returns a file handle and the name of the file system in which a requested file resides. The message is sent to the client from the server after reception of a client's request.

What is a DNS resource record?

What is meant by 3-Tier architecture?

In 3-tier Client/Server systems, the application logic (or process) lives in the middle tier and it is separated from the data and the user interface. In theory, the 3-tier Client/Server systems are more scalable, robust and flexible. Example: TP monitor, Web.

What is subnet in Networking?

A gateway operates at the upper levels of the OSI model and translates information between two completely different network architectures or data formats.

Explain the building blocks of Client/Server?

The client side building block runs the client side of the application. The server side building block runs the server side of the application.

What is SLIP (Serial Line Interface Protocol)?

It is a very simple protocol used for transmission of IP datagrams across a serial line.

What are the two types of OLTP?

TP lite, based on stored procedures. TP heavy, based on the TP monitors.

What is meant by Symmentric Multiprocessing (SMP)?

It treats all processors as equal. Any processor can do the work of any other processor. Applications are divided into threads that can run concurrently on any available processor. Any processor in the pool can run the OS kernel and execute user-written threads.

Back to Basic Networking Concepts Interview Questions and Answers page Question : What is difference between baseband and broadband transmission?

In a baseband transmission, the entire bandwidth of the cable is consumed by a single signal. In broadband transmission, signals are sent on multiple frequencies, allowing multiple signals to be sent simultaneously.

What are 10Base2, 10Base5 and 10BaseT Ethernet LANs?

10Base2?An Ethernet term meaning a maximum transfer rate of 10 Megabits per second that uses baseband signaling, with a contiguous cable segment length of 100 meters and a maximum of 2 segments 10Base5?An Ethernet term meaning a maximum transfer rate of 10 Megabits per second that uses baseband signaling, with 5 continuous segments not exceeding 100 meters per segment. 10BaseT?An Ethernet term meaning a maximum transfer rate of 10 Megabits per second that uses baseband signaling and twisted pair cabling.

What are the building blocks of Client/Server?

The client The server and Middleware.

What is wide-mouth frog?

Wide-mouth frog is the simplest known key distribution center (KDC) authentication protocol.

The middleware building block runs on both the client and server sides of an application. It is broken into three categories?

Transport stack Network OS Service-specific middleware.

What is cladding in Networking?

A layer of a glass surrounding the center fiber of glass inside a fiber-optic cable.

What is anonymous FTP and why would you use it?

Anonymous FTP enables users to connect to a host without using a valid login and password. Usually, anonymous FTP uses a login called anonymous or guest, with the password usually requesting the user's ID for tracking purposes only. Anonymous FTP is used to enable a large number of users to access files on the host without having to go to the trouble of setting up logins for them all. Anonymous FTP systems usually have strict controls over the areas an anonymous user can access.

What are the most typical functional units of the Client/Server applications?

User interface Business Logic and Shared data.

What is the difference between routable and non - routable protocols?

Routable protocols can work with a router and can be used to build large networks. Non-Routable protocols are designed to work on small, local networks and cannot be used with a router.

What is attenuation?

The degeneration of a signal over distance on a network cable is called attenuation.

What is meant by Asymmetric Multiprocessing (AMP)?

It imposes hierarchy and a division of labor among processors. Only one designated processor, the master, controls (in a tightly coupled arrangement) slave processors dedicated to specific functions.

What does the Mount protocol do?

The Mount protocol returns a file handle and the name of the file system in which a requested file resides. The message is sent to the client from the server after reception of a client's request.

What is a DNS resource record?

What is anonymous FTP and why would you use it?

What is meant by 3-Tier architecture?

What is subnet in Networking?

A gateway operates at the upper levels of the OSI model and translates information between two completely different network architectures or data formats.

Explain the building blocks of Client/Server?

The client side building block runs the client side of the application. The server side building block runs the server side of the application.

What is SLIP (Serial Line Interface Protocol)?

It is a very simple protocol used for transmission of IP datagrams across a serial line.

What are the two types of OLTP?

TP lite, based on stored procedures. TP heavy, based on the TP monitors.

What is meant by Symmentric Multiprocessing (SMP)?

Back to Basic Networking Concepts Interview Questions and Answers page Question : What is difference between baseband and broadband transmission?

What are 10Base2, 10Base5 and 10BaseT Ethernet LANs?

What are the building blocks of Client/Server?

The client The server and Middleware.

What is wide-mouth frog?

Wide-mouth frog is the simplest known key distribution center (KDC) authentication protocol.

The middleware building block runs on both the client and server sides of an application. It is broken into three categories?

Transport stack Network OS Service-specific middleware.

What is cladding in Networking?

A layer of a glass surrounding the center fiber of glass inside a fiber-optic cable.

What is passive topology?

When the computers on the network simply listen and receive the signal, they are referred to as passive because they don?t amplify the signal in any way. Example for passive topology - linear bus

What is an Object server?

With an object server, the Client/Server application is written as a set of communicating objects. Client object communicate with server objects using an Object Request Broker (ORB). The client invokes a method on a remote object. The ORB locates an instance of that object server class, invokes the requested method and returns the results to the client object. Server objects must provide support for concurrency and sharing. The ORB brings it all together.

What is a Database Server?

With a database server, the client passes SQL requests as messages to the database server. The results of each SQL command are returned over the network. The server uses its own processing power to find the request data instead of passing all the records back to the client and then getting it find its own data. The result is a much more efficient use of distributed processing power. It is also known as SQL engine.

What are the two types of transmission technology available?

Two types of transmission technology available are: (i) Broadcast (ii) point-to-point.

What is a File server?

File servers are useful for sharing files across a network. With a file server, the client passes requests for file records over network to file server.

What is the HELLO protocol used for?

The HELLO protocol uses time instead of distance to determine optimal routing. It is an alternative to the Routing Information Protocol.

What is a Web server?

This new model of Client/Server consists of thin, portable, "universal" clients that talk to super fat servers. In the simplest form, a web server returns documents when clients ask for them by name. The clients and server communicate using an RPC-like protocol called HTTP.

What is External Data Representation?

External Data Representation is a method of encoding data within an RPC message, used to ensure that the data is not system-dependent.

What is the difference between trigger and rule?

The triggers are called implicitly by database generated events, while stored procedures are called explicitly by client applications.

What is Remote Procedure Call (RPC)?

RPC hides the intricacies of the network by using the ordinary procedure call mechanism familiar to every programmer. A client process calls a function on a remote server and suspends itself until it gets back the results. Parameters are passed like in any ordinary procedure. The RPC, like an ordinary procedure, is synchronous. The process that issues the call waits until it gets the results. Under the covers, the RPC run-time software collects values for the parameters, forms a message, and sends it to the remote server. The server receives the request, unpack the parameters, calls the procedures, and sends the reply back to the client. It is a telephone-like metaphor.

Do you have any collect

What is Message Oriented Middleware (MOM)?

MOM allows general purpose messages to be exchanged in a Client/Server system using message queues. Applications communicate over networks by simply putting messages in the queues and getting messages from queues. It typically provides a very simple high level APIs to its services. MOM's messaging and queuing allow clients and servers to communicate across a network without being linked by a private, dedicated, logical connection. The clients and server can run at different times. It is a post-office like metaphor.

What are the functions of the typical server program?

It waits for client-initiated requests. Executes many requests at the same time. Takes care of VIP clients first. Initiates and runs background task activity. Keeps running. Grown bigger and faster.

Difference between the communication and transmission?

What is Protocol Data Unit?

What is EGP (Exterior Gateway Protocol)?

It is the protocol the routers in neighboring autonomous systems use to identify the set of networks that can be reached within or via each autonomous system

What is the difference between interior and exterior neighbor gateways?

Interior gateways connect LANs of one organization, whereas exterior gateways connect the organization to the outside world.

What is virtual path?

Along any transmission path from a given source to a given destination, a group of virtual circuits can be grouped together into what is called path.

What is IGP (Interior Gateway Protocol)?

It is any routing protocol used within an autonomous system.

What are the three types of SQL database server architecture?

Process-per-client Architecture. (Example: Oracle 6, Informix ) Multithreaded Architecture. (Example: Sybase, SQL server) Hybrid Architecture (Example: Oracle 7)

What are Service-specific middleware?

It is needed to accomplish a particular Client/Server type of services which includes:-Database specific middleware OLTP specific middleware Groupware specific middleware Object specific middleware Internet specific middleware and System management specific middleware.

What is Client/Server?

Clients and Servers are separate logical entities that work together over a network to accomplish a task. Many systems with very different architectures that are connected together are also called Client/Server.

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What is logical link control?

Why should you care about the OSI Reference Model?

It provides a framework for discussing network operations and design.

What is a Multi-homed Host?

It is a host that has a multiple network interfaces and that requires multiple IP addresses is called as a Multi-homed Host.

What is frame relay, in which layer it comes?

Frame relay is a packet switching technology. It will operate in the data link layer.

What protocol is used by DNS name servers?

DNS uses UDP for communication between servers. It is a better choice than TCP because of the improved speed a connectionless protocol offers. Of course, transmission reliability suffers with UDP.

What is a TP Monitor?

There is no commonly accepted definition for a TP monitor. According to Jeri Edwards' a TP Monitor is "an OS for transaction processing".

What are the advantages and disadvantages of the three types of routing tables?

The three types of routing tables are fixed, dynamic, and fixed central. The fixed table must be manually modified every time there is a change. A dynamic table changes its information based on network traffic, reducing the amount of manual maintenance. A fixed central table lets a manager modify only one table, which is then read by other devices. The fixed central table reduces the need to update each machine's table, as with the fixed table. Usually a dynamic table causes the fewest problems for a network administrator, although the table's contents can change without the administrator being aware of the change.

What are all the Extended services provided by the OS?

Ubiquitous communications Network OS extension Binary large objects (BLOBs) Global directories and Network yellow pages Authentication and Authorization services System management Network time Database and transaction services Internet services Object- oriented services

What is meant by Asymmetrical protocols?

There is a many-to-one relationship between clients and server. Clients always initiate the dialog by requesting a service. Servers are passively awaiting for requests from clients.

What are the characteristics of Client/Server?

Service Shared resources Asymmetrical protocols Transparency of location Mix-and-match Message based exchanges Encapsulation of services Scalability Integrity Client/Server computing is the ultimate "Open platform". It gives the freedom to mix-and-match components of almost any level. Clients and servers are loosely coupled systems that interact through a message-passing mechanism.

What are called Non-GUI clients, GUI Clients and OOUI Clients?

What is OLTP?

In the transaction server, the client component usually includes GUI and the server components usually consists of SQL transactions against a database. These applications are called OLTP (Online Transaction Processing) OLTP Applications typically, Receive a fixed set of inputs from remote clients. Perform multiple pre-compiled SQL comments against a local database. Commit the work and Return a fixed set of results.

What is ACID property?

ACID is a term coined by Andrew Router in 1983, which stands for Atomicity, Consistence, Isolation and Durability.

What is routing region?

What is the HELLO protocol used for?

The HELLO protocol uses time instead of distance to determine optimal routing. It is an alternative to the Routing Information Protocol.

What is IGP (Interior Gateway Protocol)?

It is any routing protocol used within an autonomous system.

What is NVT (Network Virtual Terminal)?

It is a set of rules defining a very simple virtual terminal interaction. The NVT is used in the start of a Telnet session.

What is silly window syndrome?

It is a problem that can ruin TCP performance. This problem occurs when data are passed to the sending TCP entity in large blocks, but an interactive application on the receiving side reads 1 byte at a time.

What is ICMP?

What is a DNS resource record?

What is Bandwidth?

Every line has an upper limit and a lower limit on the frequency of signals it can carry. This limited range is called the bandwidth.

What is source route?

It is a sequence of IP addresses identifying the route a datagram must follow. A source route may optionally be included in an IP datagram header.

What is RIP (Routing Information Protocol)?

It is a simple protocol used to exchange information between the routers.

What is BGP (Border Gateway Protocol)?

What is Gateway-to-Gateway protocol?

It is a protocol formerly used to exchange routing information between Internet core routers.

What is NVT (Network Virtual Terminal)?

It is a set of rules defining a very simple virtual terminal interaction. The NVT is used in the start of a Telnet session.

What is Kerberos?

Expand IDEA.

IDEA stands for International Data Encryption Algorithm.

What is Mail Gateway?

It is a system that performs a protocol translation between different electronic mail delivery protocols.

What is IGP (Interior Gateway Protocol)?

It is any routing protocol used within an autonomous system.

What is autonomous system?

It is a collection of routers under the control of a single administrative authority and that uses a common Interior Gateway Protocol.

What is packet filter?

What is multicast routing?

Sending a message to a group is called multicasting, and its routing algorithm is called multicast routing.

What is silly window syndrome?

What is the difference between routable and non- routable protocols?

Routable protocols can work with a router and can be used to build large networks. Non-Routable protocols are designed to work on small, local networks and cannot be used with a router.

What is logical link control?

What is virtual path?

Along any transmission path from a given source to a given destination, a group of virtual circuits can be grouped together into what is called path.

What are major types of networks and explain?

1. Server-based network: provide centralized control of network resources and rely on server computers to provide security and network administration 2. Peer-to-peer network: computers can act as both servers sharing resources and as clients using the resources.

What are the important topologies for networks?

1. BUS topology: In this each computer is directly connected to primary network cable in a single line. Advantages: Inexpensive, easy to install, simple to understand, easy to extend. 2. STAR topology: In this all computers are connected using a central hub. Advantages: Can be inexpensive, easy to install and reconfigure and easy to trouble shoot physical problems. 3. RING topology: In this all computers are connected in loop. Advantages: All computers have equal access to network media, installation can be simple, and signal does not degrade as much as in other topologies because each computer regenerates it.

What is difference between baseband and broadband transmission?

What is ICMP?

What are the data units at different layers of the TCP / IP protocol suite?

The data unit created at the application layer is called a message, at the transport layer the data unit created is called either a segment or an user datagram, at the network layer the data unit created is called the datagram, at the data link layer the datagram is encapsulated in to a frame and finally transmitted as signals along the transmission media.

What is difference between ARP and RARP?

The reverse address resolution protocol (RARP) allows a host to discover its Internet address when it knows only its physical address.

What is the minimum and maximum length of the header in the TCP segment and IP datagram?

The header should have a minimum length of 20 bytes and can have a maximum length of 60 bytes.

What is Bandwidth?

Every line has an upper limit and a lower limit on the frequency of signals it can carry. This limited range is called the bandwidth.

What is Protocol Data Unit?

What are the types of Transmission media?

Signals are usually transmitted over some transmission media that are broadly classified in to two categories.

a.) Guided Media: These are those that provide a conduit from one device to another that include twisted-pair, coaxial cable and fiber-optic cable. A signal traveling along any of these media is directed and is contained by the physical limits of the medium. Twisted-pair and coaxial cable use metallic that accept and transport signals in the form of electrical current. Optical fiber is a glass or plastic cable that accepts and transports signals in the form of light.

b.) Unguided Media: This is the wireless media that transport electromagnetic waves without using a physical conductor. Signals are broadcast either through air. This is done through radio communication, satellite communication and cellular telephony.

What is passive topology?

When the computers on the network simply listen and receive the signal, they are referred to as passive because they dont amplify the signal in any way. Example for passive topology -linear bus.

What is cladding?

A layer of a glass surrounding the center fiber of glass inside a fiber-optic cable.

How Gateway is different from Routers? A gateway operates at the upper levels of the OSI model and translates information between two completely different network architectures or data formats.

What is frame relay, in which layer it comes?

Frame relay is a packet switching technology. It will operate in the data link layer.

What is Beaconing?

What is NETBIOS and NETBEUI?

NETBIOS is a programming interface that allows I/O requests to be sent to and received from a remote computer and it hides the networking hardware from applications.

NETBEUI is NetBIOS extended user interface. A transport protocol designed by microsoft and IBM for the use on small subnets.

Difference between the communication and transmission.

Transmission is a physical movement of information and concern issues like bit polarity, synchronisation, clock etc.

Communication means the meaning full exchange of information between two communication media.

What are the possible ways of data exchange?

(i) Simplex (ii) Half-duplex (iii) Full-duplex.

What do you meant by "triple X" in Networks?

What is Stop-and-Wait Protocol?

In Stop and wait protocol, sender sends one frame, waits until it receives confirmation from the receiver (okay to go ahead), and then sends the next frame.

What is Stop-and-Wait Automatic Repeat Request?

Error correction in Stop-and-Wait ARQ is done by keeping a copy of the sent frame and retransmitting of the frame when the timer expires.

What is Pipelining ?

In networking and in other areas, a task is often begun before the previous task has ended. This is known as pipelining.

What is Piggy Backing?

A technique called piggybacking is used to improve the efficiency of the bidirectional protocols. When a frame is carrying data from A to B, it can also carry control information about arrived (or lost) frames from B; when a frame is carrying data from B to A, it can also carry control information about the arrived (or lost) frames from A.

What is Fixed Size Framing?

In fixed-size framing, there is no need for defining the boundaries of the frames. The size itself can be used as a delimiter.

What is Bit Stuffing?

Bit stuffing is the process of adding one extra 0 whenever five consecutive Is follow a 0 in the data, so that the receiver does not mistake the pattern 0111110 for a flag.

What is Error Control ?

What Automatic Repeat Request (ARQ)?

Error control is both error detection and error correction. It allows the receiver to inform the sender of any frames lost or damaged in transmission and coordinates the retransmission of those frames by the sender. In the data link layer, the term error control refers primarily to methods of error detection and retransmission. Error control in the data link layer is often implemented simply: Any time an error is detected in an exchange, specified frames are retransmitted. This process is called automatic repeat request (ARQ).

What is a Linear Block Code?

A linear block code is a code in which the exclusive OR (addition modulo-2) of two valid codewords creates another valid codeword.

Define Encoder?

A device or program that uses predefined algorithms to encode, or compress audio or video data for storage or transmission use. A circuit that is used to convert between digital video and analog video.

59. Define Decoder?

What is Framing?

Framing in the data link layer separates a message from one source to a destination, or from other messages to other destinations, by adding a sender address and a destination address. The destination address defines where the packet has to go and the sender address helps the recipient acknowledge the receipt.

List the steps involved in creating the checksum.a. Divide the data into sections

b. Add the sections together using 1's complement arithmetic c. Take the complement of the final sum, this is the checksum.

Compare Error Detection and Error Correction:

The correction of errors is more difficult than the detection. In error detection, checks only any error has occurred. In error correction, the exact number of bits that are corrupted and location in the message are known. The number of the errors and the size of the message are important factors.

Define Retransmission?

Retransmission is a technique in which the receiver detects the occurrence of an error and asks the sender to resend the message. Resending is repeated until a message arrives that the receiver believes is error-freed.

What is Redundancy?

The concept of including extra information in the transmission solely for the purpose of comparison. This technique is called redundancy.

What is LRC?

In LRC, a block of bits is divided into rows and a redundant row of bits is added to the whole block. It can detect burst errors. If two bits in one data unit are damaged and bits in exactly the same positions in another data unit are also damaged, the LRC checker will not detect an error. In LRC a redundant data unit follows n data units.

What is Checksum?

Checksum is used by the higher layer protocols (TCP/IP) for error detection

What are the responsibilities of Presentation Layer?

The Presentation layer is concerned with the syntax and semantics of the information exchanged between two systems.

a. Translation b. Encryption c. Compression

What are the two classes of hardware building blocks?

Nodes and Links.

What are the types of errors?

a. Single-Bit errorIn a single-bit error, only one bit in the data unit has changed b. Burst Error A Burst error means that two or more bits in the data have changed.

Which layer links the network support layers and user support layers?

The Transport layer links the network support layers and user support layers.

What are the responsibilities of Data Link Layer?

The Data Link Layer transforms the physical layer, a raw transmission facility, to a reliable link and is responsible for node-node delivery.

a. Framing b. Physical Addressing c. Flow Control d. Error Control e. Access Control

What are the responsibilities of Transport Layer?

The Transport Layer is responsible for source-to-destination delivery of the entire message.

a. Service-point Addressing b. Segmentation and reassembly c. Connection Control d. Flow Control e. Error Control

What is TDM?

TDM is a digital process that can be applied when the data rate capacity of the transmission medium is greater than the data rate required by the sending and receiving devices.

What is Synchronous TDM?

In STDM, the multiplexer allocates exactly the same time slot to each device at all times, whether or not a device has anything to transmit.

Which layers are network support layers?

a. Physical Layer b. Data link Layer and c. Network Layers

What is WDM?

WDM is conceptually the same as FDM, except that the multiplexing and demultiplexing involve light signals transmitted through fiber optics channel.

What is Round Trip Time?

The duration of time it takes to send a message from one end of a network to the other and back, is called RTT

What is Multiplexing?

Multiplexing is the set of techniques that allows the simultaneous transmission of multiple signals across a single data link.

What are the key design issues of a computer Network?

a. Connectivity b. Cost-effective Resource Sharing c. Support for common Services d. Performance

Define Routing?

The process of determining systematically hoe to forward messages toward the destination nodes based on its address is called routing.

When a switch is said to be congested?

It is possible that a switch receives packets faster than the shared link can accommodate and stores in its memory, for an extended period of time, then the switch will eventually run out of buffer space, and some packets will have to be dropped and in this state is said to congested state.

What are the criteria necessary for an effective and efficient network?

a. Performance It can be measured in many ways, including transmit time and response time. b. Reliability It is measured by frequency of failure, the time it takes a link to recover from a failure, and the networks robustness. c. Security Security issues includes protecting data from unauthorized access and virues.

Name the factors that affect the reliability of the network?

a. Frequency of failure b. Recovery time of a network after a failure

What is Protocol?

A protocol is a set of rules that govern all aspects of information communication.

Define Network?

A network is a set of devices connected by physical media links. A network is recursively is a connection of two or more nodes by a physical link or two or more networks connected by one or more nodes.

What is a node?

A network can consist of two or more computers directly connected by some physical medium such as coaxial cable or optical fiber. Such a physical medium is called as Links and the computer it connects is called as Nodes.

What is point-point link?

If the physical links are limited to a pair of nodes it is said to be point-point link.

What is Beaconing?

The process that allows a network to self-repair networks problems is called Beaconing.

The stations on the network notify the other stations on the ring when they are not receiving the transmissions. Beaconing is used in Token ring and FDDI(Fibre Distributed Data Interface) networks.

What is SLIP (Serial Line Interface Protocol)?

It is a very simple protocol used for transmission of IP datagrams across a serial line.

What is Bandwidth?

Every line has an upper limit and a lower limit on the frequency of signals it can carry. This limited range is called the bandwidth.

What is point-to-point protocol?

A communications protocol used to connect computers to remote networking services including Internet service providers.

What is Beaconing?

The process that allows a network to self-repair networks problems is called Beaconing.

The stations on the network notify the other stations on the ring when they are not receiving the transmissions. Beaconing is used in Token ring and FDDI(Fibre Distributed Data Interface) networks.

What is SLIP (Serial Line Interface Protocol)?

It is a very simple protocol used for transmission of IP datagrams across a serial line.

What is silly window syndrome?

It is a problem that can affect TCP performance. This problem occurs when data are passed to the sending TCP entity in large blocks, but an interactive application on the receiving side reads only 1 byte at a time.

What is a routing table?

A routing table contains the path information for data data packets to reach a particular inter-network. Basically this table consists of the following information, Network ID, Subnet Mask, Gateway Address, Interface(port), and netric(hops or number of gaps between two internetworking devices).

Routers add entries to routing table with the help of routing protocols.

What are the commonly used frequency bands for VSAT communication?

The commonly used frequency bands for VSAT communication arr, C-band Extended C-band(XC-band) Ku-band

In an IP address can a network ID be 127?

No, a network ID can't be 127. Because 127 is not assigned to any IP address classes. It is reserved.

What is a Passive Hub?

Passive hub is a type of hub that do not provide the amplification of signals.

These hub also do not require any external electrical supply.

What are the factors that affect the performance of NIC?

The following factors affect the performance of NIC, Bus Speed :- It depends on ISA or PCI slot. PCI has higher speed. Memory :- More the memory, better the performance. Memory Access Method :- DMA is faster than I/O method.

How session layer in OSI model is responsible for Synchronisation and recovery?

Session layer creates certain check points while transmitting volumes of data in a sequence. When there is a problem in the transmission in the middle of any bulk of data, transmission will take place from the check point where it was left. This function of Session layer is called Synchronisation and recovery.

What is Synchronous Communication?

When the server is processing a particular client that means if it is receiving and sending the information to that particular client , another client cannot acess the server at the same time . Since the server will be blocked on the first client. Hence it is not suitable in real world applciations because, mostly these days applications should process multiple clients at a time.Which is not the case here.

How to get the IP address of the Client System ?

By using following code in the Code-Behind file we can get the IP adderss of a client system on which the application is running.

What is TCB?

TCB is nothing but Transmission Control Block. It is a complex data structure which contains a considerable amount of information about each connection.

What is a Multi-homed Host ?

It is a host which has multilple network interfaces and which requires multiple IP addresses is called as a Multi-homed Host.

What is an Autonomous System ?

A collection of routers under the control of a single administrative authority which uses a common Interior Gateway Protocol is called as an Autonomous System.

What is the difference between an unspecified passive open and a fully specified passive open ?

An unspecified passive open has a server waiting for a connection request from a client. Fully Specified Passive Open:

A fully specified passive open has the server waiting for a connection from a specific client.

What is a Protocol ?

The main purpose of a protocol is for communication. Set of rules that determines how the devices communicate in a network with each other is nothing but a protocol.

What is subnet?

A generic term for section of a large networks usually separated by a bridge or router.

Difference between the communication and transmission.

Transmission is a physical movement of information and concern issues like bit polarity, synchronisation, clock etc.

What is SAP?

Series of interface points that allow other computers to communicate with the other layers of network protocol stack.

What is frame relay, in which layer it comes?

Frame relay is a packet switching technology. It will operate in the data link layer.

What is Beaconing?

What is NETBIOS and NETBEUI?

NETBIOS is a programming interface that allows I/O requests to be sent to and received from a remote computer and it hides the networking hardware from applications.

What is RAID?

A method for providing fault tolerance by using multiple hard disk drives.

What is Brouter?

Hybrid devices that combine the features of both bridges and routers.

What is point-to-point protocol?

A communications protocol used to connect computers to remote networking services including Internet service providers.

What is attenuation?

The degeneration of a signal over distance on a network cable is called attenuation.

What is Protocol Data Unit?

machines that are generating and using the data. The control field specifies whether the PDU frame is a information frame (I - frame) or a supervisory frame (S - frame) or a unnumbered frame (U - frame).

What is ICMP?

What are the data units at different layers of the TCP / IP protocol suite?

What is the minimum and maximum length of the header in the TCP segment and IP datagram?

The header should have a minimum length of 20 bytes and can have a maximum length of 60 bytes.

How Gateway is different from Routers?

A gateway operates at the upper levels of the OSI model and translates information between two completely different network architectures or data formats

What is attenuation?

The degeneration of a signal over distance on a network cable is called attenuation.

What is MAC address?

The address for a device as it is identified at the Media Access Control (MAC) layer in the network architecture. MAC address is usually stored in ROM on the network adapter card and is unique.

What is Bandwidth?

Every line has an upper limit and a lower limit on the frequency of signals it can carry. This limited range is called the bandwidth.

What is ICMP?

What are the types of Transmission media?

Signals are usually transmitted over some transmission media that are broadly classified in to two categories.

What is the range of addresses in the classes of internet addresses?

Class A 0.0.0.0 - 127.255.255.255

Class B 128.0.0.0 - 191.255.255.255

Class C 192.0.0.0 - 223.255.255.255

Class D 224.0.0.0 - 239.255.255.255

Class E 240.0.0.0 - 247.255.255.255

What is MAC address?

The address for a device as it is identified at the Media Access Control (MAC) layer in the network architecture. MAC address is usually stored in ROM on the network adapter card and is unique.

What are the possible ways of data exchange?

(i) Simplex (ii) Half-duplex (iii) Full-duplex.

What do you mean by data communication?

Ans: It is the exchange of data between two devices via some form of transmission medium such as wire cable. The communicating system must be part of a communication system made up of a combination of hardware and software.The effectiveness of a data communication system depends on three fundamental characteristics: delivery, accuracy and timeliness.

What is half-duplex?

Ans: It is the mode of communication between two devices in which flow of data is bi-directional but not at the same time. ie each station can transmit and receive but not at the same time. E.g walkie-talkies are half-duplex system.

What is a network?

Ans: It is a set of devices connected by communication links. A node can be a computer or any other device capable of sending and/or receiving data generated by other nodes on the network.

What is distributed processing?

Ans: It is a strategy in which services provided by the network reside at multiple sites.

What is point to point connection?

Ans:It provides a dedicated link between two devices. The entire capacity of the link is reserved for transmission between the two devices e.g. when we change the TV channels by remote control we establish a point to point connection between remote control and TV control system.

What is a topology?

Ans: Topology of a network is defined as the geometric representation of the relationship of all the links and linking devices (node) to one another.Four basic topologies are star, bus, ring and mesh. Star – Here each device has a dedicated point to point link only to a central controller called hub.

Define internet?

Ans: It is a network of networks.

What is TCP/IP protocol model?

Ans: It is a five layered model which provides guidelines for the development of universally compatible networking protocols. The five layers are physical, data link, network, transport and application.

What is ISO-OSI model?

Ans: Open Systems Interconnection or OSI model was designed by the International Organization for Standardization (ISO) .It is a seven layer model. It is a theoretical model designed to show how a protocol stack should be implemented. It defines two extra layers in addition to TCP/IP model. Session -It was designed to establish, maintain, and synchronize the interaction between communicating system.

What is multiplexing?

Ans: Multiplexing is the process of dividing a link, the phycal medium, into logical channels for better efficiency. Here medium is not changed but it has several channels instead of one.

How data is transmitted over a medium?

Ans: Data is transmitted in the form of electromagnetic signals.

Compare analog and digital signals?

Ans: Analog signals can have an infinite number of values in a range but digital signal can have only a limited number of values.

What are the factors on which data rate depends?

Ans: Data rate ie.how fast we can send data depends upon i) Bandwidth available ii) The levels of signals we can use iii) The quality of the channel (level of noise

What is sampling?

Ans: It is the process of obtaining amplitude of a signal at regular intervals.

Define pulse code modulation?

Ans: Pulse code Modulation modifies pulses created by PAM to create a completely digital signal. For this PCM first quantizes the PAM pulse. Quantization is the method of assigning integral values in a specific tange to sampled instances.PCM is made up of four separate processes: PAM, quantization, binary encoding and line encoding.

What are the modes of data transmission? Ans: Data transmission can be serial or parallel in mode In parallel transmission, a group of bits is sent simultaneously, with each bit on a separate line.In serial transmission there is only one line and the bits are sent sequentially.

What is Synchronous mode of data transmission?

Ans: It is a serial mode of transmission.In this mode of transmission, bits are sent in a continuous stream without start and stop bit and without gaps between bytes. Regrouping the bits into meaningful bytes is the responsibility of the receiver.

What is FDM?

Ans: In frequency division multiplexing each signal modulates a different carrier frequency. The modulated carrier combines to form a new signal that is then sent across the link. Here multiplexers modulate and combine the signal while demultiplexers decompose and demodulate. Guard bands keep the modulating signal from overlapping and interfering with one another.

What is TDM ?

Ans: In TDM digital signals from n devices are interleaved with one another, forming a frame of data. Framing bits allow the TDM multiplexer to synchronize properly.

What are the different Guided Media?

Ans: The media which provides a conduct from one device to another is called a guided media. These include twisted pair cable, coaxial cable, and fiber-optic cable.

What do you mean by wireless communication?

Ans: Unguided media transport electromagnetic waves without using a physical conductor. This type of communication is referred as wireless communication. Here signals are broadcaster through air and thus available to anyone who has a device to receive it.

What are the switching methods?

Ans: There are three fundamental switching methods: circuit switching, packet switching, And message switching.In circuit switching, a direct physical connection between two devices is created by space division switches, time division switches or both. In packet switching data is transmitted using a packet switched network. Packet switched network is a network in which data are transmitted in independent units called packets.

What are the types of errors?

Ans: Errors can be categorized as a single-bit error or burst error. A single bit error has one bit error per data unit. A burst error has two or more bits errors per data unit.

Ans: In parity check, a parity bit is added to every data unit so that the total number of 1s is even (or odd for odd parity).Simple parity check can detect all single bit errors. It can detect burst errors only if the total number of errors in each data unit is odd.In two dimensional parity checks, a block of bits is divided into rows and a redundant row of bits is added to the whole block.

Define cyclic redundancy check (CRC).

Ans: C RC appends a sequence of redundant bits derived from binary division to the data unit. The divisor in the CRC generator is often represented as an algebraic polynomial.

What do you mean by flow control?

Ans: It is the regulation of sender’s data rate so that the receiver buffer doesn’t become

Define stop and wait ARQ.

Ans: In stop and wait ARQ, the sender sends a frame and waits for an acknowledgement from the receiver before sending the next frame.

Define Selective Repeat ARQ?

Ans: In Selective Repeat ARQ, multiple frames can be in transit at the same time. If there is an error, only unacknowledged frame is retransmitted.

What is HDLC?

Ans: It is a bit oriented data link protocol designed to support both half duplex and full duplex communication over point to point and multi point links.HDLC is characterized by their station type,configuration and their response modes.

What do you mean by point to point protocol stack?

Ans: Point to point protocol uses a stack of other protocol to use the link, to authenticate the parties involved, and to carry the network layer data. Three sets of protocols are defined: link control protocol, Authentication protocol, and network control protocol.

What do you mean by line control protocol?

Ans: It is responsible for establishing, maintaining, configuring, and terminating links.

What do you mean by network control protocol?

Ans: Network control protocol is a set of protocols to allow the encapsulation of data coming from network layer protocol that requires the services of PPP

What do you mean by Bluetooth?

Ans: It is a wireless LAN technology designed to connect devices of different functions such as telephones, notebooks, computers, cameras, printers and so on. Bluetooth LAN Is an adhoc network that is the network is formed spontaneously? It is the implementation of protocol defined by the IEEE 802.15 standard.

What do you mean by subnetting?

Ans: Subnetting divides one large network into several smaller ones. It adds an intermediate level of hierarchy in IP addressing.

What are the disadvantages of fiber optics cable?

Ans: The disadvantages of fiber optics cable over twisted pair cable are Cost-It is expensive Installation/maintenance-Any roughness or cracking defuses light and alters the signal Fragility-It is more fragile.

What are the factors for evaluating the suitability of the media ?

Ans: The factors are cost,throughput,attenuation,Electromagneric interference(EMI),securtty.

What do you mean by ALOHA ?

Ans: It is the method used to solve the channel allocation problem .It is used for: i)ground based radio broadcasting ii)In a network in which uncoordinated users are competing for the use of single channel. It is of two types: 1.Pure aloha 2.Slotted aloha

What is slotted ALOHA?

Ans: In this method time is divided into discrete intervals,each interval corresponding to one frame.It requires user to agree on slot boundaries.Here data is not send at any time instead it wait for beginning of the next slot.Thus pure ALOHA is tuened into discrete one.

What do you mean by non persistent CSMA(carrier sense multiple access) ?

Ans: Here if no one else is sending the station begins doing so itself.However if the channel is already in use,the station does’t continuously sense it rather it waits for a random period of time and then repeats.It leads better channel utilization but longer delay.

What is FDDI?

Ans: It is high performance fiber optic token ring LAN running at 100Mbps over distance up 1000 stations.FDDI access is limited by time.A FDDI cabling consist of two fiber rings. i)one transmitting clockwise ii)one transmitting counterclockwise

What is Repeaters ?

Ans: A receiver receives a signal before it becomes too weak or corrupted,regenerates the original bit pattern,and puts the refreshed copy back onto the link.It operates on phycal layer of OSI model.

What is Routers ?

Ans: Router relay packets among multiple interconnected networks.They receive packet from one connected network and pass it to another network.They have access to network layer addresses and certain software that enables them to determine which path is best for transmission among several paths.They operate on phycal,data link and network layer of OSI model.

What do you mean by Data Terminal Equipment(DTE) ?

Ans: It is any device that is source of or destination for binary digital data.At phycal layer it can be a terminal computer. They generate or consume information.

What do you mean by protocol stack ?

Ans: The list of protocols used by certain system ,one protocol per layer is called protocol stack.

What do you mean by peer ?

Ans: Entities comprising the corresponding layers on different machines are called peers.It may be hardware device processes human being peers communicate by using protocol.

What are the advantages of broadcast network.

Ans: a single communication channel is shared by all computers. packets are transmitted and received by all the computer. address field is attached to whom it is intended. multicasting is used in network.

What are the design issue of layers ?

Ans: The design issue of layer are • Addressing technique.ie source and destination address • Types of communication • Error control • Order of message. • Speed matching • Multiplexing and demultiplexing.

What are the protocols in transport layer ?

Ans: The protocols defined in transport layer are • TCP • UDP

Define UDP ?

Ans: It is unreliable connectionless protocol.It is used for one-shot,client-server type,requesr-reply queries and applications in which prompt delivery is required than accuracy.

Define IP ?

Ans: Internetwork protocol (IP) is the transmission mechanism used by TCP/IP protocol.It is an unreliable and connectionless datagram protocol.It provides no error checking and tracking.

What are the information that a computer attached to a TCP/IP internet must possesses ?

Ans: Each computer attached to TCP/IP must possesses the following information • Its IP addesss • Its subnet mask • The IP addesss of the router. • The Ip address of the name server.

What is TELNET ?

Ans: TELNET is a client –server application that allows a user to log on to a remote machine,giving the user access to the remote system. TELNET is an abbreviation of terminal Network.

What is Network Virtual Terminal ?

Ans: A universal interface provided by TELNET is called Network Virtual Terminal(NVT) character set.Via this interface TELNET translates characters (data or command) that come from local terminal into NVT form and delivers them to the network.

What is Hypertext Transfer Protocol(HTTP) ?

Ans: It is the main protocol used to access data on the World Wide Web .the protocol transfers data in the form of plain text,hypertext,audio,video,and so on. It is so called because its

What is URL ?

Ans: It is a standard for specifying any kind of information on the World Wide Web.

What is HTML ?

Ans: Hypertext Markup Language (HTML) is a language for creating static web pages

IT Professional

THE NETWORKING INTERVIEW QUESTION AND ANSWER

Author : IT Professional

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IT Professional

THE NETWORKING INTERVIEW QUESTION AND ANSWER

Author : IT Professional

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