CSPP-54015 Advanced Network Design

Homework 2, Due at the beginning of class by email, Monday, April 15th.  Email to Veronica, "V", at "V <vyessa@gmail.com>"

 Read the BGP and OSPF chapter on the class website.  In between those chapters, watch "bgprap" on Youtube.

Excercises

    1)  For the following network topologies, indicate the simplest type of routing protocol which would do the job and why:

    a) A star topology network with a single router in the middle.

    b) A topology in which 10 floors of an office building have switches on each floor with routers between floors.  Duplicate routers are provided for redundancy.

    c) A multi-building  corporate campus network with multiple redundant connections and routers between buildings with some of the links being wireless links which are relatively unreliable due to electrical storms.

    2) Starting from bootup, for a 15 node ring network, how long will it take for all the nodes to have the same routing state if updates are done every 10 seconds and a distance vector protocol is used.  How about for a link state routing protocol?

    3) I mentioned in class that one of the improvements in RIP 2 is password authentication and we talked about injecting false topologies.  Can you think of another way to protect from someone injecting false topologies if for some reason password protection was not feasible?

    4) Why do link state routing protocols use flooding when each router typically has a complete network map and could send LSA updates directly to each router in the network?

    5) Some network architectures include separate data and control connection, so that the traffic can be kept separate. Why would this be an advantage? Of the 4 main routing protocols we discussed in class, which would benefit the most from a network with separate data and control connections? Are there security implications of such a network?

    6)  If delays are recorded as 16-bit numbers for a 100 router network and delay numbers are exchanged twice a second in order to optimize routing, how much bandwidth per line is used up by the delay component of the distributed routing algorithm.  Assume each router has 3 links to other routers.

    7)  In class, we talked about how to use Dijkstra to find the shortest path through a network.  Describe how to use Dijkstra to find two path through a network such that if any link failed on one path, the other path would work.  You can assume that routers don't fail, only links between routers fail.


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