Re: from the academic side of the house

[Simon Leinen <simon () limmat switch ch>]

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.