GATE Computer Science Engineering(CSE) 2027 Test: Routers & Routing Algorithms

In the following pairs of OSI protocol layer/sub-layer and its functionality, the INCORRECT pair is

Which of the following is NOT true with respect to a transparent bridge and a router?

In a network of LANs connected by bridges, packets are sent from one LAN to another through intermediate bridges. Sincemore than one path may exist between two LANs, packets may have to be routed through multiple bridges. Why is thespanning tree algorithm used for bridge-routing?

Consider a simple graph with unit edge costs. Each node in the graph represents a router. Each node maintains a routing table indicating the next hop router to be used to relay a packet to its destination and the cost of the path to the destination through that router. Initially, the routing table is empty. The routing table is synchronously updated as follows. In each updation interval, three tasks are performed.
i. A node determines whether its neighbours in the graph are accessible. If so, it sets the tentative cost to each accessible
neighbour as 1. Otherwise, the cost is set to ∞.
ii. From each accessible neighbour, it gets the costs to relay to other nodes via that neighbour (as the next hop).
iii. Each node updates its routing table based on the information received in the previous two steps by choosing the minimum cost.

For the graph given above, possible routing tables for various nodes after they have stabilized, are shown in the following options. Identify the correct table.

Consider a simple graph with unit edge costs. Each node in the graph represents a router. Each node maintains a routing table indicating the next hop router to be used to relay a packet to its destination and the cost of the path to the destination through that router. Initially, the routing table is empty. The routing table is synchronously updated as follows. In each  updation interval, three tasks are performed.
i. A node determines whether its neighbours in the graph are accessible. If so, it sets the tentative cost to each accessible neighbour as 1. Otherwise, the cost is set to ∞.
ii. From each accessible neighbour, it gets the costs to relay to other nodes via that neighbour (as the next hop).
iii. Each node updates its routing table based on the information received in the previous two steps by choosing the minimum cost.

Continuing from the earlier problem, suppose at some time t, when the costs have stabilized, node A goes down. The cost from node F to node A at time (t + 100) is :

A group of 15 routers are interconnected in a centralized complete binary tree with a router at each tree node. Router icommunicates with router j by sending a message to the root of the tree. The root then sends the message back down torouter j. The mean number of hops per message, assuming all possible router pairs are equally likely is

A group of 15 routers are interconnected in a centralized complete binary tree with a router at each tree node. Router icommunicates with router j by sending a message to the root of the tree. The root then sends the message back down torouter j. The mean number of hops per message, assuming all possible router pairs are equally likely is

Which of the following is TRUE about the interior gateway routing protocols Routing Information Protocol (RIP) and Open Shortest Path First OSPF

Consider the following statements about the routing protocols. Routing Information Protocol (RIP) and Oprn Shortest Path
First (OSPF) in an IPv4 network.
I. RIP uses distance vector routing
II. RIP packets are sent using UDP
III. OSPF packets are sent using TCP
IV. OSPF operation is based on link-state routing
Which of the above statements are CORRECT?

In a RSA cryptosystem, a participant A uses two prime numbers P = 13 and q = 17 to generate here public and private keys. If the public key of A is 35 , then the private key of A is __________ .

In a RSA cryptosystem, a participant A uses two prime numbers P = 13 and q = 17 to generate here public and private keys. If the public key of A is 35 , then the private key of A is __________ .

In a RSA cryptosystem, a participant A uses two prime numbers P = 13 and q = 17 to generate here public and private keys. If the public key of A is 35 , then the private key of A is __________ .

Consider a 128 x 10³bits/second satellite communication link with one way propagation delay of 150 milliseconds.
Selective retransmission (repeat) protocol is used on this link to send data with a frame size of 1 kilobyte. Neglect the transmission time of acknowledgement. The minimum number of bits required for the sequence number field to achieve 100% utilization is ________.

Start and stop bits do not contain any "information" but are used in serial communication for

In serial communication employing 8 data bits, a parity bit and 2 stop bits, the minimum band rate required to sustain atransfer rate of 300 characters per second is

How many bytes of data can be sent in 15 seconds over a serial link with baud rate of 9600 in asynchronous mode with oddparity and two stop bits in the frame?

Count to infinity is a problem associated with

For the network given in the figure below, the routing tables of the four nodes A, E, D and G are shown. Suppose that F has estimated its delay to its neighbors, A, E, D and G as 8, 10, 12 and 6 msecs respectively and updates its routing table using distance vector routing technique.

Consider the following three statements about link state and distance vector routing protocols, for a large network with 500network nodes and 4000 links.
[S1]: The computational overhead in link state protocols is higher than in distance vector protocols.
[S2]: A distance vector protocol (with split horizon) avoids persistent routing loops, but not a link state protocol.
[S3]: After a topology change, a link state protocol will converge faster than a distance vector protocol.Which one of the following is correct about S1, S2, and S3 ?

A router uses the following routing table:

packet bearing a destination address 144.16.68.117 arrives at the router. On which interface will it be forwarded?