[96263] in North American Network Operators' Group
Re: from the academic side of the house
daemon@ATHENA.MIT.EDU (Simon Leinen)
Wed Apr 25 17:58:23 2007
From: Simon Leinen <simon@limmat.switch.ch>
To: "Steven M. Bellovin" <smb@cs.columbia.edu>
Cc: Jim Shankland <nanog@shankland.org>, bmanning@karoshi.com,
nanog@merit.edu
In-Reply-To: <20070425132214.7C9E7766670@berkshire.machshav.com> (Steven
M. Bellovin's message of "Wed, 25 Apr 2007 09:22:14 -0400")
Date: Wed, 25 Apr 2007 23:55:17 +0200
Errors-To: owner-nanog@merit.edu
Steven M Bellovin writes:
> Jim Shankland <nanog@shankland.org> wrote:
>> (2) Getting this kind of throughput seems to depend on a fast
>> physical layer, plus some link-layer help (jumbo packets), plus
>> careful TCP tuning to deal with the large bandwidth-delay product.
>> The IP layer sits between the second and third of those three items.
>> Is there something about IPv6 vs. IPv4 that specifically improves
>> perfomance on this kind of test? If so, what is it?
> I wonder if the router forward v6 as fast.
In the 10 Gb/s space (sufficient for these records, and I'm not
familiar with 40 Gb/s routers), many if not most of the current gear
handles IPv6 routing lookups "in hardware", just like IPv4 (and MPLS).
For example, the mid-range platform that we use in our backbone
forwards 30 Mpps per forwarding engine, whether based on IPv4
addresses, IPv6 addresses, or MPLS labels. 30 Mpps at 1500-byte
packets corresponds to 360 Gb/s. So, no sweat.
Routing table lookups(*) are what's most relevant here, because the other
work in forwarding is identical between IPv4 and IPv6. Again, many
platforms are able to do line-rate forwarding between 10 Gb/s ports.
--
Simon, AS559.
(*) ACLs (access control lists) are also important, but again, newer
hardware can do fairly complex IPv6 ACLs at line rate.
