Computer networks questions and answers pdf

It might consist of an e-mail system, a message accessing board and one or more Web site portals. Extra-net — A network that connects people within this company with people who are outside of the company is called extra-net.

It happens within a secure ,password protected network. Answer: Network Topology is refers to the way computers and its peripheral environment is configured to form networks.

Answer: Here all nodes are connected to a hub. Packets sent to the hub. Again packets are sent by Hub to the destination. Answer: Here all nodes are connected in a circle. Token is used for transferring data from computers. Here nodes waits for token to send. Answer: These are the larger one connections of networks. How do we connect two devices?

By the help of connecting links only. The connecting links are nothing but the protocols which are used to make the computers or other devices communicate each. In the very simple language with the help of protocols, only two devices can communicate with each other.

Devices can be anything like computers, printer, mobile devices. These devices in networking or even called as nodes. For example, let's say that you've decided that all IP addresses up to.

All IP addresses above. Answer:- 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 meters and a maximum of 2 segments. Question 87 Explain what is redirector? This comes under presentation layer.

The standard protocol has been defined between the terminal and the PAD, called X. Together, these three recommendations are often called "triple X" Read More Answers. Answer:- ui Server-based networkPeer-to-peer networkPeer-to-peer network, computers can act as both servers sharing resources and as clients using the resources. Server-based networks provide centralized control of network resources and rely on server computers to provide security and network administration Read More Answers. Answer:- in It is a project started by IEEE to set standards that enable intercommunication between equipment from a variety of manufacturers.

It is a way for specifying functions of the physical layer, the data link layer and to some extent the network layer to allow for interconnectivity of major LAN protocols. It consists of the following Media access control MAC is the lower sublayer of the data link layer that contains some distinct modules each carrying proprietary information specific to the LAN product being used.

The modules are Ethernet LAN Question 91 Explain difference between bit rate and baud rate. Bit rate is the number of bits transmitted during one second whereas baud rate refers to the number of signal units per second that are required to represent those bits. O Answer:- Please share your answers. M Read More Answers. It also handles both control and error messages.

Question 93 Tell me can we use static and dynamic routing in one network? Answer:- As Saurabh said; we can use static and Dynamic Routing in one network. However Dyanmic Routing is used to have the best path no matter what the status of the physical links. All routing protocols have some sort of shortest-path or lowest-cost or best-choice algorithm to help you weigh all the options available.

Static routing can be used in a small network to reduce the work of the network administrator or to use a particular route only to forward the packet; we need static routing.

Question 94 Tell me what are the advantages and disadvantages of the three types of routing tables? Answer:- 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. Answer:- The header should have a minimum length of 20 bytes and can have a maximum length of 60 bytes. Answer:- ba 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. This sublayer is responsible for maintaining the link between computers when they are sending data across the physical network connection.

Answer:- 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 in destinations within its own region, but knowing nothing about the internal structure of other regions.

C Answer:- One of the main causes of congestion is that traffic is often busy. If hosts could be made to transmit at a uniform rate, congestion would be less common. Another open loop method to help manage congestion is forcing the packet to be transmitted at a more predictable rate. This is called traffic shaping.

O Question Explain what are Digrams and Trigrams? M Answer:- The most common two letter combinations are called as digrams. The most common three letter combinations are called as trigrams. Question Explain what is silly window syndrome in Computer Networks? Answer:- 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.

Question What is source route in Computer Networks? Answer:- 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. Answer:- It is a set of rules defining a very simple virtual terminal interaction.

Answer:- The Default subnet mask for this Ip address is But the the subnet mask is Applications are user interfacing and is in a format understandable by the user. The application layer provides a user with various application services, which a user decides upon ui the communication. Word is an application that a user users at the application layerTransport:This layer multiplexes data. The need for multiplexing, is that there could be many services that would want to communicate with different destinations.

Along with this this layer also provides a user with different reliabilty modes depending upon the protocol usedNetwork:This layer is responsible for logical addressing to identify the network where the reciveing d station isData link:This layer is where the data gets another tag with the physical address of the device, to identify exactly what PC the data is destined to in the network identified by the network layer.

The physcial address often depends upon the technolgy that you are using ethernet, token ring, frame relay, PPP etc. Also the data gets split in to series of bits of 0s and 1s and sent to the lower layerPhysical:This is the layer where the data in form of bits recieved from the data link layer el gets transmitted in form of electrical signals to the destination Read More Answers. PDUs b. PRAMs d. C Answer:- B. Peer Entities Read More Answers.

Why do we use these techniques? VLAN's break up broadcast domains in layer 2 switch network. You can achieve this by using either a Layer 3 switch or a router. Answer:- State the technical steps required for data transmission from server to server via a router and switch Read More Answers. Question Suppose a person would like to access a file on another computer connected via LAN while working with safe mode.

What should he do? Question Tell me what is VPN? Question ba What does negotiation mean when discussing network protocols? Half-duplex devices let you send and receive, but only one-way at a time.

If you've ever used a walkie-talkie, then you know what half-duplex conversations sound like. You have to push the TALK button to send your message. But as long as you are holding the TALK key, you can't hear what anyone else is saying. You must release the button to receive. Full duplex actually, full duplex is nothing new. In fact, you already know exactly what it sounds like. Your corded or cordless phones are full-duplex devices letting you and your caller speak simultaneously without any dropouts in either one of your voices.

Half- and Full-Duplex ModeEach switch port can operate in either half-duplex or full-duplex mode. As a result, when the switch is connected to another network ui device that is capable of autonegotiation, the two devices communicate common speeds and duplex modes to each other. Then, the highest common capabilities for both devices become the operating modes. The switch has the following operating priorities To reduce attenuation, repeaters are used to boost the signal strength.

Question IP though unreliable it implements routing of network information across the nodes upto the destination. But TCP cannot do this it implements O only the end-to-communication i. M Question Explain what are the important topologies for networks? Answer:- 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.

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. 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.

Question Tell us why do we have a minimum and maximum cable length requirement? Answer:- The min and max cable length is required because the signals can travel effectively without loosing their strength to that extent you can increase the cable length apart from preferred by using the repeaters after the length so that the signals will be boosted again.

Question What is cladding in Computer Networks? Common cladding materials include vinyl and extruded or roll-formed aluminum Read More Answers. Question G Explain what is passive topology?

Answer:- 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 lo passive topology - linear bus. Answer:- lG. In an Exchange environment, using. Think of this as a type of email cache file. This leaves the emails on the server, but also stores a copy of emails since your last sync on the local machine. Question d Suppose you have been given 1 printer and 1 IP Address for installing it in a Networking Environment How will you do it?

The printer is now ready to use. Because it is considered to be the most efficient IGP interior gateway protocol. Question What is the difference between routable and non- routable protocols?

Answer:- 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 Read More Answers. Question How many levels of signalling is possible with such modulation, in other words what is the number of symbols?

Answer:- Please share your views. Answer:- Short for Media Access Control address, a hardware address that uniquely identifies each node of a network.

The MAC layer interfaces directly with the network medium. Consequently, each different type of network medium requires a different MAC layer. In a session 2. In a LAN 3.

In a WAN 4. It is a kind of virtual database used to manage the devices in a network. It consists of record the of network entities e. The database is hierarchical tree structured and entries are addressed through object identifiers. Question Explain why logical address required is in OSI model? State the difference between guide media and unguide media Answer:- Please share your answers.

DNS is resolve the web site name to IP address or you can say. How does it get a message to the network looking for its IP address and the location of its operating system boot files? The same message might contain the name of the machine that has the boot files on it. If the boot image location is not specified, the workstation sends another UDP message to query the server. Answer:- Short for Multistation Access Unit also abbreviated as MSAU , a token-ring network device that physically connects network computers in a star topology while lo retaining the logical ring structure.

One of the problems with the token-ring topology is that a single non-operating node can break the ring. The MAU solves this problem because it has the ability to short out non-operating nodes and maintain the ring structure. A MAU is a special type of hub. Network layer is responsible for the packets to be delivered with reliability for every link i. But E1 leased line is very Costly. Vpn also need internet connection to send data from source to server.

O Answer:- 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. Question Explain what is the advantage and disadvantage of local area networks? Answer:- In transport layer two protocols are working TCP , transmission control protocol and UDP , user datagram protocol , TCP is also know as reliable protocol , means it is using handshake process , where client requtest to server then establish the connection and then transfer the packet then terminates it.

In UDP , no relaibilty but packets are safe. Question Explain what is autonomous system? Answer:- Autonomous system has been assigned a number which differentiates it from other autonomous systems to communicate. Answer:- Recovery Console for example if you install a software in exsisting windows and due to the software if the system have some problem you can choose Recovery console at Start -programs-accessories-system tools-Recovery consoleenter it and you can see the Timetable of Recovery console select the previous date of which you installed and select Restore.

Question lG Explain 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? Answer:- 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. Broadband :In this type. Point to Point :In this type of technology there are multiple connections transmission lines between 2 hosts. C What is layer-3 switch in Computer Networks? Answer:- A layer 2 switch provides connectivity but doesn't act upon the packets at all.

A layer 3 switch provides connectivity but can also provide routing, access lists, QOS and even security. O These are usually much more expensive switches with IOS's installed.

They are best used in video conferencing to keep video packets together through QOS. For video, your cable should run directly to the layer 3 switch and not pass through any other lessor switch to avoid tiling, delays and other issues that affect video quality. Question Explain what is Active Directory?

How does it work? Answer:- In windows and environment ads is a power full sercice ,active directory mainly used for maintaing and promotion of entire company into centralized network administration. Question Explain what is ipv6? How many octects is it? The best example of stupidity leading to the problem is universities handing out public IP address to students and facility on their networks.

A corporation would be insane to hand out public ip addresses to staff members. IPv6 default subnet is I'm sure it's implemented somewhere, but I've not seen it. The solution to running out of IP addresses is better management of IPv4 addresses.

The students then return to their networks and implement their text book learning's in their networks. Then these students wonder why things are all messed up on their networks. You should Class 'C' addressing on your private, smaller networks. It'll work out much better for you. Question Explain what is Private IP? Answer:- The address which can't be routed through public internet are private ip addressesand it is scheam of saving public addressex:in class A range is Question Explain what is the difference between collision domain and broadcast domain?

Answer:- G 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. Question ba Explain what is point-to-point protocol? Answer:- In networking, the Point-to-Point Protocol is commonly used to establish a direct connection between two nodes.

Its primary use has been to connect computers using lG a phone line, though it is also occasionally used over broadband connections. Question ui What is difference between layer 2 and layer 3 switch?

How much bandwidth support by V. What is difference between V. Router also provide packet filtering by using acess list and when connect two or more network together and use logical addressing IP. Besides, router use routing table to make path selection and forward packet el to remote network.

How will you restore this file Without using Safe Mode Option? C as appropriate to your situation,u can solve it by repair this folder in the first repair in Win XP if u know name of his folder..

Keep in mind we cannot use any other additional equipment? This then translates the IP address of the server, which is likely to be a It keeps track of which server, and where it is going, so it can use the same 'real' IP address on the Internet for both of them. Question Explain how Gateway is different from Routers? Answer:- Gateway is nothing but the final point that the data crosses finally in a network, it is mostly used for user authentication which router cannot provide.

Gateways can provide authentication to anonymous users, it is used when u have only one single network. It is less costly. Whereas router is used for routing between different networks, providing routing tables and deciding best path for the data to travel. It is used when you have more than one networks. It is more costly. Question Explain benefits of VPN? An IP VPN is a partitioned private network constructed over a shared IP-based backbone that utilizes technologies to ensure privacy of data.

Question which protocol is used for retrieving mails? How will you connect each devices and configure those devices? Answer:- ba This is using different network build purpose, so connect first router to first switch and connect 10 nodes with first switch, this is one network ex How will you read that switch? Answer:- ui A switch can have an Ip address for telnetting purpose. So, if you telnet to the switch, and if you have no password on Telnet you can access the switch provided that there is no privileged mode password set and then 'Show Run' , you can read the running configuration.

Answer:- in Piggybacking is gaining access to restricted communication channel by using session that another user has already established. Piggybacking can be defeated by logging off before leaving a workstation or terminal or by initiating a protected mode, such as via a screensaver, that requires re-authentication before access can be resumed.

C What advantage does REX offer other similar utilities? O Read More Answers. Question M Explain what does the Mount protocol do? Answer:- 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. Question Tell me what is the difference between interior and exterior neighbor gateways?

Answer:- Interior gateways connect LANs of one organization, whereas exterior gateways connect the organization to the outside world. Question What is a pseudo tty in Computer Networks?

Answer:- A pseudo tty or false terminal enables external machines to connect through Telnet or rlogin. Without a pseudo tty, no connection can take place. Question What is the difference between an unspecified passive open and a fully specified passive open?

Answer:- 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. Question What is the function of Transmission Control Block? Answer:- A TCB is a complex data structure that contains a considerable amount of information about each connection. Answer:- ba 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. Answer:- ui Terminal emulation is the ability to make one computer terminal appear like some other terminal.

Terminal emulation is used to give the users the ability to log on and get direct access to legacy programs in a mainframe operating system. The emulation program runs like any other workstation application as a separate program task.

An individual channel can be uniquely identified by its virtual e channel and virtual path number. The insertion of VCs enables to implement policies for allocating the physical channel bandwidth, which enables to support quality of service in applications. C Question The network address made available to the transport layer should use a uniform numbering plan 1.

Question What is Beaconing in Computer Networks? Answer:- Beaconing is a process which allows the network to render their network problems by them-selfToken ring and FDDI Fibre Distributed Data Interface networks make use of this process.

Question Explain what are headers and trailers? How are they added and removed? Answer:- Headers and trailers are the concepts of OSI model. Headers are information structures which identifies the information that follows, such as a block of bytes in communication. Trailer is the information which occupies several bytes at the end of the block of the data being transmitted. They contain error-checking data which is useful for confirming the accuracy and status of the transmission.

During communication of data the sender appends the header and passes it to the lower layer while the receiver removes header and passes it to upper layer. Answer:- The internet layer packs data into data packets known as IP datagrams, which contain source and destination address information that is used to forward the datagrams between hosts and across networks.

The Internet layer is also responsible for routing of IP datagrams. Its job is to allow the host to insert packets to the internet,when data is sent, each layer treats all the information it receives as data and adds control information to the front of that data.

This control information is called a header, and the addition of a header is called encapsulation. When data is received, the opposite procedure takes place as each layer removes its header before passing the data to the layer above.

There are two types of IGP lG 1. Distance-vector routing protocol 2. Link-state routing protocol. Answer:- d Using a single IP address and locally splitting it up so that this single network IP address can actually be used on several interconnected local networks is known as netted IP. Answer:- System recovery is a process of an overall plan for system recovery so that we are prepared if the system fails.

System recovery is a tow part system,including system e recovery backup and system recovery restore. The SR Wizard, located in Backup, does the backup portion. The wizard backs up the system state, system services, and all the disks that are associated with the operating system components. T he restore portion restores all the disk signatures, volumes, and partitions on at a minimum the disks that is need to start the computer.

C A system failure will cause the system to freeze, reboot, or stop functioning altogether. System failure can occur because of a hardware failure or a severe software issue, example, when a hard disk drive fails, it will prevent the computer from being able to boot. When a system fail occurs we use system recovery to recover the system back to its condition. O Question Tell me what is the default subnet mask for an ipv6 address?

M Answer:- A default subnet mask Question Suppose If you are given the IP address can u tell how many computers can be connected? What do you look at? Question Tell me how to transfer some data periodically using RTP protocol without any loss?

Answer:- Suppose i want to send some periodic information during the normal voip communication using RTP. How can I make sure that this data can be reached there without any loss?? And also is there any method to send data in such a way Read More Answers. Question What is the difference between networking and telecom domain? Will network protocol testing will come under telecom domain?

Question What is ost file? Answer:- In Microsoft Office Outlook , a new offline folder file format is introduced that offers greater storage capacity for items and folders and supports multilingual G Unicode data. An offline file folder is used to keep a local copy of your Exchange Server mailbox on your computer. The items in your. Steps for offline file folder On the File menu, click Work Offline. Select or clear the Prompt me at startup so I may choose to work offline or online check box, and then click OK.

If you clear the check box, Outlook will automatically start offline if a connection to the server is lo not available. Click Yes to copy the data from the server to your new Offline Folder file.

Answer:- lG Printer driver replication means if you have a network printer and if you want to share it among other Citrix servers, then we can replicate that driver to be used by all the Citrix servers or for few selected Citrix servers, however that driver should be installed in the Citrix server from which we are replicating the driver. Printer mapping relates to mapping the driver software for specific domain users only, these can be dont by right clicking on the driver or by the printer option on the left plane of Citrix presentation server console.

C Question What is port address in Computer Networks? Answer:- O A port number is a way to identify a specific process to which an Internet or other network message is to be forwarded when it arrives at a server.

For the Transmission Control Protocol and the User Datagram Protocol, a port number is a bit integer that is put in the header appended to a message unit. This port M number is passed logically between client and server transport layers and physically between the transport layer and the Internet Protocol layer and forwarded on. If you move your client machine to a different subnet, the client will send out its discover message at boot time and work as usual.

However, when you first boot up there you will not be able to get back the IP address you had at your previous location regardless of how little time has passed. Disadvantage Your machine name does not change when you get a new IP address. This only presents a problem if other clients try to access your machine by its DNS name. Question What is the difference between physical address and logical address?

Answer:- Logical address of yhe any nic card is ip address of the sysytem. Question What is the default subnet mask for IPV6? Unicast addresses identify a single network device, anycast and multicast addresses identify a group of network devices. IPv6 addresses are bit, compared to the 32 bit addresses of v4 and look like this example - dbada2e: Ipv6 does not use subnetting. G Answer:- Switch is a data link layer device that connect multiple LAN segments to form lo a single network segment.

In switch when we transmit the data first it examine the data packets for source and destination, then the switch forward the data packet to the appropriate destination. Switch minimize the possibility of collision of data packets by reducing ba collision domains. Collision domain are the network segment between two network devices, when the two devices transmit a data at a time then collision will occur. In such case both the device stop working.

Then it starts to work for a specific period lG of time and retransmit the data. Switches reduces the collision using micro-segmentation. Answer:- d Active Directory is a directory service. The term directory service refers to two things - a directory where information about users and resources is stored and a service or services that let you access and manipulate those resources.

Active Directory is a way to manage all elements of your network, including computers, groups, users, domains, security policies, and any type of user-defined objects.

It melds several NT services and tools that have functioned separately so far - User el Manager for Domains, Server Manager, Domain Name Server - and provides additional functions beyond these services and tools.

Because these are platform-independent in protocols, Unix, Macintosh, and other clients can access resources in the same fashion as Windows clients. C POD Ping of Death is a type of attack at computer in a network that involves sending of a larger size malicious ping to a computer.

Question O What is the size of ping to death packet? Answer:- M A ping is normally 64 bytes in size. Many computers can not handle larger than the maximum ip packet size, which is 65,bytes. Sending a ping of this size can crash the target computer.

Question What is the difference between simplex and duplex? Answer:- simplex- one way transmission. Both transmission and reception takes place. Full duplex:- both txn and recep Answer:- A routing protocol is used by router to dynamically find all the networks in the internetwork and to ensure that all routers have the same routing table.

Basically G routing protocol determines the path of a packet through an internetwork. A routed protocol can be used to send user data through the established enterprise, when routers know about all networks. Routed protocols are assigned to an interface and determine the method of packet delivery. Question ba What you will do, if you computer boots to the black screen?