List six access technologies. Classify each one as home access, enterprise access, or wide-area wireless access. [15 points]
2. Suppose two hosts, A and B, are separated by 10,000 kilometers and are connected by a direct link of R = 2 Mbps. Suppose the propagation speed over the link is 2.5 _ 10^8 meters/sec. [20 points] a. Calculate the bandwidth-delay product,R _dprop.
b. Consider sending a file of 900,000 bits from Host A to Host B. Suppose the file is sent continuously as one large message. What is the maximum number of bits that will be in the link at any given time? c. Provide an interpretation of the bandwidth-delay product. d. What is the width (in meters) of a bit in the link? Is it longer than a football field? e. Derive a general expression for the width of a bit in terms of the propagation speed s, the transmission rate R, and the length of the link m.
3. Suppose you wanted to do a transaction from a remote client to a server as fast as possible. Would you use UDP or TCP? Why? [15 points]
4. Consider an HTTP client that wants to retrieve a Web document at a given URL. The IP address of the HTTP server is initially unknown. What transport and application-layer protocols besides HTTP are needed in this scenario? [15 points]
5. Why is it that voice and video traffic is often sent over TCP rather than UDP in today’s Internet? (Hint: The answer we are looking for has nothing to do with TCP’s congestion-control mechanism.) [15 points]
6. What are the two most important network-layer functions in a datagram network? What are the three most important network-layer functions in a virtual circuit network? [15 points]
7. Consider the network below. A)suppose that this network is a datagram network. Show the forwarding table in router A, such
1. that all traffic destined to host H3 is forwarded through interface 3.
2. Suppose that this network is a datagram network. Can you write down a forwarding table in
router A, such that all traffic from H1 destined to host H3 is forwarded through interface 3, while all traffic from H2 destined to host H3 is forwarded through interface 4? (Hint: this is a trick question.)
3. Now suppose that this network is a virtual circuit network and that there is one ongoing call between H1 and H3, and another ongoing call between H2 and H3. Write down a forwarding table in router A, such that all traffic from H1 destined to host H3 is forwarded through interface 3, while all traffic from H2 destined to host H3 is forwarded through interface 4.
4. Assuming the same scenario as (c), write down the forwarding tables in nodes B, C, and D.
8. In CSMA/CD, after the fifth collision, what is the probability that a node chooses K = 4? The result K = 4 corresponds to a delay of how many seconds on a 10 Mbps Ethernet? [15 points]
9. Why would the token-ring protocol be inefficient if a LAN had a very large perimeter? [15 points]
10. Consider three LANs interconnected by two routers, as shown in Figure below. [20 points] a. Assign IP addresses to all of the interfaces. For Subnet 1 use addresses of the form 192.168.1.xxx; for Subnet 2 uses addresses of the form 192.168.2.xxx, and for Subnet 3 use addresses of the form 192.168.3.xxx.
b. Assign MAC addresses to all of the adapters. c. Consider sending an IP datagram from Host E to Host B. Suppose all of the ARP tables are up to date. Enumerate all the steps, as done for the single-router. d. Repeat (c), now assuming that the ARP table in the sending host is empty (and the other tables are up to date).
11. How are IP addresses similar to MAC addresses? In what ways are the two addresses different [15 points]?
12. What is Wireshark? Aside from being a free tool what are some of the reasons, this is such a widely used tool [10 points]?
13. What kind of information do you get on the statistics sub-menu on Wireshark.. mention three-four main info [10 points]?