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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: packet reordering at exchange points
On Wed, 10 Apr 2002 15:48:36 +0100 "Peter Galbavy" <[email protected]> wrote: > I am still waiting (after many years) for anyone to explain to me the > issue of buffering. It appears to be completely unneccesary in a > router. OK, what I am missing? Unless I'm misunderstanding your question, this seems relatively simplistic and the need for buffers on routes is actually quite obvious. Imagine a router with more than 2 interfaces, each interface being of the same speed. Packets arrive on 2 or more interfaces and each need to be forwarded onto the same outbound interface. Imagine packets arrive at exactly or roughly the same time. Since the bits are going out serially, you're gonna need to buffer packets one behind the others on the egress interface. Similar scenarios occur when egress interface capacity is less than some rate or aggregate rate wanting to exit via that interface. John
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