Unformatted text preview: (2) When a layer changes, it is only needed to make sure that the interface is same, then layers above or below it are not affected. (3) Because the structure can be separated, it is easy to find the suitable solution for each layers, and easy to maintain them. Disadvantage: (1) One layer can not use the services that the layer provided are not adjacent of it. 3. A and B lose communication only if the all link have failure. So the probability that A and B lose communication is 0.01 when there are two links. And if there are three parallel links, the probability is 0.001. 4. 5. a. It is not necessary for A and B to implement the link layer protocols. b. It is only necessary for X to implement the link layer protocols....
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- Spring '09
- virtual circuit, Link Layer protocols