CS 6250: Midterm Exam Name:Instructor: Dr. Clark October 19, 2005CS 6250Fall 2005 - Midterm ExamProblem Possible Score1 202 103 164 185 166 20Total 100This test is closed book and closed notes. Answer the questions in the space provided. When answering ques-tions, please state any and all assumptions you are making.1CS 6250: Midterm Exam Name:Part 1: Protocol Layering (20 points)List, in order, the five protocol layers we discussed. For each layer, provide the following 4 things: 1) Name of thelayer, 2) Service(s) provided by this layer to the upper layer, 3) A specific standard protocol that fits in this layer. 4)Where (on which devices) this layer is implemented.2CS 6250: Midterm Exam Name:Part 2: IPv6 (10 points)What steps did the designers of IPv6 take to make packet header processing more efficient? There are several thingsthat were done. List them all for full credit.3CS 6250: Midterm Exam Name:Part 3: Network Programming (16 points)1. (8 pts) I’ve said that our TCP programs must “perform all I/O operations in a loop”. What is meant by this?Explain why it is important.2. (8 pts) What is meant by the term “byte ordering”? Explain why it is important in the context of networkprogramming.4CS 6250: Midterm Exam Name:Part 4: Routing (18 points)1. (6 pts) What is meant by the term domain based routing?2. (6 pts) What mechanisms does BGP use to prevent routing loops?3. (6 pts) Why do the administrators of the Tier 1 networks restrict route advertisements to netmasks of no morethan 22 bits?5CS 6250: Midterm Exam Name:Part 5: Network Address Translation (16 points)1. (8 pts) What specific problems does NAT solve? What benefits does a NAT device provide? As part of youranswer, give a specific example of a case where NAT is deployed.2. (8 pts) What problems are created by the use of NAT? As part of your answer, give a specific example of acase where a NAT devices creates such a problem.6CS 6250: Midterm Exam Name:Part 6: Mobile IP (20 points)Consider a mobile node MN from network X. The user of MN wishes to communicate with a corresponding nodeCN in network Y. The node MN moves from X to a foreign network A.1. (10 pts) Describe the sequence of messages that are required in Mobile IPv4 so that MN and CN can continueto communicate. Give the purpose of each message, where it is from, where it is to, and the path that it takes.Include both the user data messages and the Mobile IP control messages.2. (10 pts) Now, consider the case where CN moves to foreign network B while MN is still in the foreign networkA. Can CN and MN still communicate? (Does Mobile IP support both endpoints moving?) Show the messageflow to indicate how it will succeed or fail in this