[6bone] Re: IPv6-only IXP's are absolutely wrong

[Gert Doering]

Hi,

On Mon, Oct 21, 2002 at 10:18:42AM -0400, Eric Gauthier wrote:
> I don't know about the various IX's, but the I2 gigapop that our University
> uses is concerned about this.  If I remember correctly (not that the exact 
> numbers are important), but IPv4 is in an ethernet frame with type 0x0800 and 
> IPv6 is in an ethernet frame with type 0x86dd, so layer 3/4 aware switches 
> will likely handle these frames differently.  In our case, the Cisco 12,000 
> and 6500's that we're using are great for IPv4 packets (they handle them
> in hardware), but IPv6 packets are handled in software so we don't expect 
> nearly the same type of performance.  I'd imagine that something like this 
> is what they're alluding to.  

This is definitely relevant for the individual participants - but for
the IXP switch (which is strictly layer 2 *only*, at least for all IXes
that I know), L3/4 forwarding performance should not be an issue.

One issue that I see is multicast (neighbor discovery etc) which isn't
seen on an IPv4 unicast exchange switch.

Gert Doering
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