Computer Networks

14. Write the keys for understanding the link state routing?

The three keys for understanding the algorithm are,

·         Knowledge about the neighborhood. 

·         Routing to all neighbors.

·         Information sharing when there is a range.

15. How the packet cost referred in distance vector and link state routing?

In distance vector routing, cost refer to hop count while in case of link state routing, cost is a weighted value based on a variety of factors such as security levels, traffic or the state of the link.

16. Define Reliable flooding?

            It is the process of making sure that all the nodes participating in the routing protocol get a copy of the link state information from all the other nodes.

17. What are the features in OSPF?

·         Authentication of routing messages.

·         Additional hierarchy.

·         Load balancing.

18. Define Subnetting?

            Subnetting provides an elegantly simple way to reduce the total number of network numbers that are assigned. The idea is to take a single IP network number and allocate the IP address with that network to several physical networks, which are now referred to as subnets.

19. What are the different types of AS?

·         Stub AS

·         Multi homed AS

·         Transit AS

20. What is an Area?

            An Area is a set of routers that are administratively configured to exchange link-state information with each other. There is one special area- the backbone area, also known as area 0.

21. What is Source Specific Multicast?      

            SSM , a receiving host specifies both a multicast group and a specific host .the receiving host would then receive multicast addressed to the specified group, but only if they are from the special sender.

22. What is meant by congestion?

            Congestion in a network occurs if user sends data into the network at a rate greater than that allowed by network resources.

23. Why the congestion occurs in network?

            Congestion occurs because the switches in a network have a limited buffer size to store arrived packets.

24. What are the rules of non boundary-level masking?

·         The bytes in the IP address that corresponds to 255 in the mask will be  repeated in the sub network address 

·         The bytes in the IP address that corresponds to 0 in the mask will change to  0 in the sub network address 

·         For other bytes, use the bit-wise AND operator.

25. What is LSP?

            In link state routing, a small packet containing routing information sent by a router to all other router by a packet called link state packet.