Assignment handed out on Wednesday, March 7, 2001

Due in Recitation on 3/8/2001:

• Finish reading Scalable Transport for Transparent Mobile Internetworking. Your writing/discussion assignment:

  Mobile IP is a store and forward-like protocol that enables a computer on the network to change IP addresses transparently. The protocol is backwards compatible with IP, but requires the presence of agents on the network. In particular, a home agent is required, but a foreign agent is not. Foreign agents, however, appear to add some overhead (e.g., one or more extra network hops to the mobile host). Give at least one circumstance where having a foreign host would actually improve communication performance, despite the additional hop(s) required. (Hint: Consider a video stream or a large file being sent to a mobile host, and think about how mobile networks differ from wired networks in terms of bandwidth, latency, and reliability)
  
  Bonus questions: Why do you think that Mobile IP is not in widespread use today?

• Read The Click Modular Router. This is a very techinical read (a la sections I-IV of the RAID paper). Approach this paper by determining what problem the authors are trying to solve (In the Abstract and Introduction). Notice that the top of page 265 outlines what each subsequent chapter is about. A quick skim shows that the architecture section describes the key approaches being used to solve the problem. Given how technical this paper is, focusing on the architecture section will probably give you the best ratio of understanding per time spent. Skimming the rest of the paper is a good idea. Anything more than skimming will take a lot of time, since really understanding all the details would require a huge amount of background. Sometime in the future, if/when you are a network wizard, you will have read enough of this paper to know when you should come back to get the rest of the story.