Suppose computers A and B have IP addresses 10.105.1.113 and 10.105.1.91 respectively and they both use the same net mask N. Which of the values of N given below should not be used if A and B should belong to the same network?

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 in the previous question are changed to 2 and the distance vector algorithm is used again until all routing tables stabilize. How many links will now remain unused?

Which one of the following is not a client-server application?

A main memory unit with a capacity of $$4$$ megabytes is built using $$1M \times 1$$-bit $$DRAM$$ chips. Each $$DRAM$$ chip has $$1K$$ rows of cells with $$1K$$ cells in each row. The time taken for a single refresh operation is $$100$$ nanoseconds. The time required to perform one refresh operation on all the cells in the memory unit is