quiz105key - worse performance for some sources. 2. DVMRP...

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Quiz 5 Key CNT 5106C 18 March 2010 Instructions: Write your last name, then first initial in upper righthand corner of answer sheet, and write “Quiz 5” centered at top. Answer all questions. 1. What are two basic approaches to building multicast trees? Describe each. 2. Compare DVMRP and PIM. KEY 1. Two basic approaches to building a multicast tree are (a) source-based tree and (b) shared tree. In source-based tree, each source may have its own tree for distributing multicast messages that may optimize delay, etc. for its transmissions. In the shared tree approach, all sources share a single spanning tree for their multicast transmissions. This is a bit simpler (there is only one tree to build and to remember), but may have
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Unformatted text preview: worse performance for some sources. 2. DVMRP uses source-based trees, based on RPF and pruning (i.e., it assumes downstream routers have multicast subscribers until told otherwise). The reverse path forwarding is independent of the underlying unicast routing protocol. It only has a single mode of operation. PIM also uses source-based trees, but has two modes of operation: dense mode and sparse mode. Dense mode uses flood and prune based on RPF, similar to DVMRP (push approach). Sparse mode uses center-based trees with a rendezvous point (RP) to form the multicast tree upon request of the subscribers. It supports source-specific multicast (SSM)....
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This note was uploaded on 01/17/2012 for the course CNT 5106c taught by Professor Helmy during the Spring '09 term at University of Florida.

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