Some Typical Questions in Computer Networks for GATE CSE Exam

Hello, friends today in this Computer Science Study Material for Gate I am going to discuss some conceptual questions in computer networks. Here are these questions and their answer.

Q1.How does address resolution is performed in Arp?

Answer: The table lookup approach to address resolution requires a data structure that contains information about address bindings. The table consists of an array. Each entry in the array contains a pair [P, H] where P is a protocol address and H is the equivalent hardware address. A separate address binding table is used for each physical network. Consequently, all IP addresses in a given table have the same prefix. For example, the following address binding table corresponds to a network with the class C number therefore, each IP address in the table will begin with 197.15.3 prefix. The chief advantage of this table lookup approach is that a table can store the address bindings for an arbitrary set of computers on a given network.

Q2: What are  MIB variables?

Answer: MIB (Management Information Base ) variables: MIB is a set of named items that an SNMP agent understands. To monitor or control a remote computer, a manager must fetch or store values to MIB variables. Because SNMP does not specify a set of MIB variables, the design is flexible. The separation of communication protocol from the definition of the objects permits to define MIB variable as needed. there are MIB variables that correspond to protocols like UDP, TCP, IP, and ARP, as well as MIB variables for network hardware such as Ethernet. In addition to simple variables such as integers that correspond to counters, a MIB can include a variable that corresponds to a table or an array.

tricky questions in computer networks

Q3: How physical addressing is performed in WAN? 

Answer: WAN networks operate similarly to a LAN. Each WAN technology defines the exact frame format a computer uses when sending and receiving data. Each computer connected to a WAN is assigned a physical address. When sending a frame to another computer, the sender must supply the destination’s address.

Many WANs use a hierarchical addressing scheme that makes forwarding more efficient.Hierarchical addressing scheme divides an address into multiple parts. The simplest scheme divides address into two parts; the first part identifies packet switch, and second part identifies computer
attached to that packet switch.

Q4: What is CIDR?

Answer: CIDR is a new addressing scheme for the internet which allows for more efficient allocation of IP addresses that old class A, B, and C addressing scheme. Instead of being limited to network identifier (or prefixes) of 8, 16, or 24 bits, CIDR currently uses prefixes anywhere from 13 to 27 bits. Thus, the block of addresses can be assigned to a network as small as 32 hosts or to those with 500,000 hosts. This allows for address assignments that much more closely fit an organization’s specific need.

A CIDR address includes the standard 32- bit address and also information on how many bits are used for the network prefix. For example in CIDR address, the /25 indicates that the first 25 bits are used to identify unique network leaving the remaining bits to identify the specific host.

Q5: Does it make sense for two domain servers to contain exactly the same set of names? Why or why not? 

Answer: Yes. It is very advantageous for two domain servers containing the same set of names. If there is only one server than traffic on one server would be intolerable because it would be the only server to receive all the request and handle them appropriately. If there is more than one server containing the same set of data then geographically closet server will respond thus reducing the load on one server. Also if one server is down due to some problem then another server containing the same set of data can be used to fulfill the incoming requests.

I hope that this Study Material for gate Computer Science will be beneficial for computer science students. Later we will also discuss some other important questions in computer networks for gate cse exam.