Re: [lisp] IPv6 UDP checksum issue

[Marshall Eubanks <[e-mail]>]

On Aug 4, 2009, at 9:08 AM, Sam Hartman wrote:

>>>>>> "Marshall" == Marshall Eubanks <[e-mail]> writes:
>
>    Marshall> Dear Brian;
>    Marshall> On Aug 2, 2009, at 6:15 PM, Brian E Carpenter wrote:
>
>> Lars,
>>>
>>> It seems to me that it would not violate the spirit of RFC2460
>>> if we added a rule that stacks MUST follow the RFC2460 rule by
>>> default but MAY deviate from it for duly configured tunnel end
>>> points in routers (where "router" is strictly as defined in
>>> section 2 of 2460 and the Note in that section). That would
>>> fully preserve the requirement as far as hosts and applications
>>> go.
>>>
>
> This was exactly the intention of
>
>    Marshall> http://tools.ietf.org/html/draft-eubanks-chimento-6man-00
>
>    Marshall> We intend to rev this shortly and comments would be
>    Marshall> appreciated.
>
> Margaret brought up a set of questions for LISP if it's going to send
> 0 UDP checksums, basically surrounding what happens when a packet on
> such a tunnel is corrupted and gets received by a node that either
> does or does not understand the tunneling protocol.  One of these
> questions hinged on the expected behavior of receivers seeing a 0 UDP
> checksum.
>
>
> I suggest that your draft
>
> 1) Indicate whether receivers should be specially configured to accept
> 0 checsums or whether all stacks should accept 0 checksums.
>

I personally think that receivers SHOULD require special configuration  
to
accept UDP 0 checksums. Receivers that are acting as tunnel end points  
are
likely to require special optimizations anyway.

> 2) Adapt her questions as questions that IETF specs considering this
> exception need to answer to make sure that their protocol will work
> correctly in this mode.
>

OK, thanks, will look at this.

Marshall

> --Sam
>