Chapter 4 Network Layer and Routing
1) What are the two main functions of a datagram-based network layer? What additional functions does a VC-based network layer have? 2) List and describe the ATM network service models. 3) Compare and contrast link-state and distance-vector routing algorithms. 4) Discuss how a hierarchical organization of the Internet has helped to scale to millions of users. 5) It is necessary that every autonomous system use the same intra autonomous routing algorithm? Why or why not? Section 4.5
6) What is the decimal equivalent of the IP address 184.108.40.206 ? 7) Consider a LAN to which ten host interfaces and three router interfaces are attached. Suppose all three LANs use class C addresses. The IP addresses for the 13 devices will be identical in which of the first 32 bits? 8) Consider a router with three interfaces. Suppose all three interfaces use class C addresses. Will the IP addresses of the three interfacess necessarily have the same first 8 bits? 9) Suppose there are three routers between source and destination hosts. Ignoring fragmentation, an IP segment sent from source host to destination host will travel over how many interfaces? How many routing tables will be indexed to move the datagram from source to destination? 10) Suppose an application generates chunks 40 bytes of data every 20 msec, and each chunk gets encapsulated in a TCP segment and then an IP datagram. What percentage of each datagram will be overhead and what percentage will be application data? 11) Consider sending a 3000 byte datagram into a link that has a MTU of 500 bytes. Suppose the original datagram is stamped with the identification number 422. How many fragments are generated? What are their characteristics? 12) Consider Figure 4.5-2. Starting with the original table in D, suppose that D receives from A the following advertisement: destination
of hops to
Will the table in A change? If so how?
13) Contrast and compare the advertisements used by RIP and OSPF. 14) RIP advertisements typically announce the number of hops to various destinations. BGP updates, on the otherhand, announce the __________ (fill in the blank) to the various destinations. 15) Why are different inter-AS and intra-AS protocols used in the Internet? Section 4.6
16) Describe three different types of switching fabrics commonly used in packet switches. 17) Why are buffers needed at the output ports of switches? Why are buffers needed at the input port of switches? Section 4.7
18) Compare and contrast the IPv4 and the IPv6 header fields. Do they have any fields in common? 19) It has been said that IPv6 tunnels through IPv4 routers, IPV6 treats the IPv4 tunnels as link layer protocols. Do you agree with this statement? Why or why not? Section 4.8
20) What is an important difference between implementing the multicast abstract via multiple unicasts, and a single network (router) supported multicast group. 21) True or False: when a host joins a multicst group, it must change its IP address to be that of the multicast group it is joining. 22) What are the roles played by the IGMP protocol and a wide-area multicast routing protocol? 23) What is the difference between a group-shared tree and a source-based tree in the context of multicast routing? 24) True or False: In reverse path forwarding, a node will receive multiple copies of the same packet. True or False: In reverse path forwarding, a node may forward multiple copies of a packet over the same outgoing link. 25) Classify each of the following multicast routing algorithms as either a source-baed tree approach or a group-shared tree approach: DVMRP, MOSPF, CBT, PIM Sparse Mode, PIM Dense Mode. Problems
1) Let us consider some of the pros and cons of a connection-oriented versus connectionless architecture. a) Suppose that in the network layer, routers were subjected to "stressful" conditions that might...
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