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QoS Routing

We wrote earlier that the only way to alter performance for a multimedia flow was by changing the schedule in a router or switch.

However, there is another way, which is to select a different path. There are two problems with this: firstly, alternate path routing is a very complex problem, and few protocols currently support this on the basis of requests and current network conditions; secondly, alternate paths are there for some reason, and that reason is usually that some other user is about to use them. Hence it may be a bad idea economically to make use of alternate paths that deviate very far from the best current obvious route. The jury is still out on this topic.