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Re: [RRG] The use of UDP in LISP
On 2007-12-12 13:23, Dino Farinacci wrote:
Dino Farinacci has suggested this text :
o When a IPv6 router is using a UDP header as part of a tunnel
encapsulation,
it MAY compute a UDP checksum. The IPv6 router on the other side of the
tunnel receives a UDP checksum of non-zero it MUST compute the checksum
according to [UDP-spec]. When an IPv6 router uses a UDP header for
tunnel
encapsulation and sets the UDP checksum field to 0, the IPv6 router
on the
other side of the tunnel MUST not compute the checksum on the received
packet. This procedure allows tunnel routers to behave the same for
tunnel encapsulating IPv4 and IPv6 packets.
At the least AMT and LISP would require this, and I suspect that
there will be others.
I don't actually understand the "require". If you'd written "People
Required in the sense if you want to get the protocols into product.
Oh, you mean required by "fast-cheap-reliable; pick two". Sure.
coding AMT and LISP would find this convenient" I'd understand it,
And it isn't the code, it is the gates. ;-)
Just another form of software ;-)
but surely the tunnel end-points will know whether they are
generating or receiving IPv4 or IPv6 packets?
Yes, but what is your point?
Only that logically, the two cases can be handled differently.
It certainly makes sense that this would be poor engineering.
I also don't understand why it would be considered safe, in the
absence of a header checksum - are you deeming that the tunnel must
have error detection at layer 2?
Yes. As well as the low probably of bit-error rates, matching sockets
and mis-routing, all that would have to work in unison to have a real
problem.
Sure. But don't forget to document that layer 2 error-proofing is needed.
Thanks
Brian
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