Re: [MBONED] [Fwd: I-D Action:draft-eubanks-chimento-6man-00.txt]

[Dino Farinacci <dino at cisco.com>]

> > > The argument made by the draft authors is that since multicast
> > > packets already have a UDP header with a checksum, there is no
> > > additional benefit and indeed some cost to nodes to both compute and
> > > check the UDP checksum of the outer (encapsulating) header.   
> > > However,
> > > Consequently, IPv6 should make an exception to the rule that the UDP
> > > checksum MUST not be 0, and allow tunneling protocols to set the
> > > checksum field of the outer header only to 0 and skip both the  
> > > sender
> > > and receiver computation.
> >
> > It is worse than that for AMT. Since the control packets are  
> > encapsulated in
> > an IGMP packet format. There is an IGMP checksum performed as well,  
> > then on
> > top of that encapsulated in UDP, with the UDP checksum performed  
> > there too.
> >
> > So please note that the burden might be less in the control-plane,  
> > but it is
> > less necessary to do UDP checksum as well in this case. I think you
> > shouldn't deprecate the behavior in the spec, but outline how double
> > check-summing is occurring in this case.
>
> Dino, I believe the current spec must be deprecated because it
> specifically forbids a 0 checksum.
>
> Greg

The AMT spec?

Dino