GATE CS Routing Protocols: Shortest Path, Flooding, Distance Vector, Link State questions

An ISP having an address block $202.16.0.0/15$ assigns a block of $6000$ IP addresses to a client, using the classless internet domain routing (CIDR) super-netting approach. Which of the following address blocks can be assigned by the ISP?

Consider a file of size $4$ million bytes being transferred between two hosts connected via a path consisting of three consecutive links of bandwidth $2$ Mbps , $500$ kbps , and $1$ Mbps , respectively. All processing delays and propagation delays are negligible. Assume that there is no other background traffic over the path and no other additional …

Consider the routing protocols given in List I and the names given in List II: …

Consider a network path $\mathrm{P}-\mathrm{Q}-\mathrm{R}$ between nodes $\mathrm{P}$ and $\mathrm{R}$ via router $\mathrm{Q}$. Node $\mathrm{P}$ sends a file of size $10^6$ bytes to $\text{R}$ via this path by splitting the file into chunks of $10^3$ bytes each. Node $\text{P}$ sends these chunks one after the other without any wait time …

Consider the entries shown below in the forwarding table of an $\text{IP}$ router. Each entry consists of an $\text{IP}$ prefix and the corresponding next hop router for packets whose destination $\text{IP}$ address matches the prefix. The notation " /$\mathrm{N}$ " in a prefix indicates a subnet mask with the most significant $\mathrm{N}$ bits set …

Which of the following statements is/are $\text{INCORRECT}$ about the $\textsf{OSPF (Open Shortest Path First)}$ routing protocol used in the Internet?

Consider a network with three routers $\text{P, Q, R}$ shown in the figure below. All the links have cost of unity. The routers exchange distance vector routing information and have converged on the routing tables, after which the link $\text{Q-R}$ fails. Assume that $\text{P}$ and $\text{Q}$ send out routing updates at random times, each at the same …

Consider a computer network using the distance vector routing algorithm in its network layer. The partial topology of the network is shown below. The objective is to find the shortest-cost path from the router $R$ to routers $P$ and $Q$. Assume that $R$ does not initially know the shortest routes to $P$ and $Q$. Assume that $R$ has three …

Consider the following statements about the functionality of an $\textsf{IP}$ based router. A router does not modify the $\textsf{IP}$ packets during forwarding. It is not necessary for a router to implement any routing protocol. A router should reassemble $\textsf{IP}$ fragments if the $\textsf{MTU}$ of the outgoing link is larger than the size of …

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

Which of the following are used to generate a message digest by the network security protocols? RSA SHA-$1$ DES MD5

Consider the following three statements about link state and distance vector routing protocols, for a large network with $500$ network 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 …

An IP machine $Q$ has a path to another $IP\ machine\ H$ via three $IP\ routers \ R1, R2,$ and $R3$. $Q-R1-R2-R3-H$ $H$ acts as an $\text{HTTP}\ server$, and $Q$ connects to $H$ via $\text{HTTP}$ and downloads a file. Session layer encryption is used, with $\text{DES}$ as the shared key encryption protocol. Consider the following four …

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

An IP router implementing Classless Inter-domain Routing (CIDR) receives a packet with address $131.23.151.76$. The router's routing table has the following entries: …

Consider a network with five nodes, $N1$ to $N5$, as shown as below. The network uses a Distance Vector Routing protocol. Once the routes have been stabilized, the distance vectors at different nodes are as follows. N1: $(0, 1, 7, 8, 4)$ N2: $(1, 0, 6, 7, 3)$ N3: $(7, 6, 0, 2, 6)$ N4: $(8, 7, 2, 0, 4)$ N5: $(4, 3, 6, 4, 0)$ Each distance vector …

Consider a network with five nodes, $N1$ to $N5$, as shown as below. The network uses a Distance Vector Routing protocol. Once the routes have been stabilized, the distance vectors at different nodes are as follows. N1: $(0, 1, 7, 8, 4)$ N2: $(1, 0, 6, 7, 3)$ N3: $(7, 6, 0, 2, 6)$ N4: $(8, 7, 2, 0, 4)$ N5: $(4, 3, 6, 4, 0)$ Each distance vector …

Consider a network with $6$ routers $R1$ to $R6$ connected with links having weights as shown in the following diagram. Suppose the weights of all unused links are changed to $2$ and the distance vector algorithm is used again until all routing tables stabilize. How many links will now remain unused?

Consider a network with $6$ routers $\textbf{R1}$ to $\textbf{R6}$ connected with links having weights as shown in the following diagram. All the routers use the distance vector based routing algorithm to update their routing tables. Each router starts with its routing table initialized to contain an entry for each neighbor with the weight of the …

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