North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: It's Ars Tech's turn to bang the IPv4 exhaustion drum
What I was told is that, yes, the packet get routed through the ASIC, but it has to go there twice... Hence reducing the pps by a factor of 2 compare to IPv4. Some vendors had shortcuts that, if the prefix len was < 64, only one pass was necessary. Caveat, this may not be true for all vendors or all models of all vendors. YMMV. - Alain. On 8/19/08 4:22 PM, "Kevin Oberman" <[email protected]> wrote: >> Date: Tue, 19 Aug 2008 14:30:38 -0400 >> From: Alain Durand <[email protected]> >> >> On 8/19/08 1:50 PM, "[email protected]" <[email protected]> wrote: >> >>>> In practice, many routers require the packet to go twice in the hardware if >>>> the prefix length is > 64 bits, so even though it is a total waste of >>>> space, >>>> it is not stupid to use /64 for point-to-point links and even for >>>> loopbacks! >>> >>> Could you provide some documentation on this? First I've heard about it. >> >> Ask your favorite router vendor. This has been confirmed to me by at least 3 >> major one we use. > > Odd. I have asked both of our router vendors and they have confirmed > that they route in the ASIC based on the full address, not just the > first 64 bits. (I believe one of them based on actual testing. I am > suspicious of the other.) > > That said, one does use a few bits for something else (port) and does > not load them into the FIB, so I believe they route on 120 bits, not > 128. > > I'd love to get complete verification of the real facts of this.
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