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Re: [RRG] The use of UDP in LISP

On 2007-12-12 10:19, Marshall Eubanks 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
coding AMT and LISP would find this convenient" I'd understand it,
but surely the tunnel end-points will know whether they are
generating or receiving IPv4 or IPv6 packets?

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?

     Brian

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