Re: transmech substantial comments

[Brian E Carpenter <brc@zurich.ibm.com>]

The guidelines for DSCP and tunnels are in RFC 2983, called, strangely
enough, "Differentiated Services and Tunnels." It's Informational.

   Brian

Jun-ichiro itojun Hagino wrote:
> 
> > >  4) We specify the that the ToS byte for the v4 header is 0 unless otherwise
> > > specified, and refer to a couple of documents for that.  A problem with this
> > > is that I'm not sure if those documents actually tackle the problem of
> > > *different* protocol-version tunnels -- rather, they (AFAIR) discuss the
> > > issues of ToS byte in v4-over-v4, where mapping (or not mapping) the ToS
> > > byte from the inner IP header is a trivial excercise.
> > >
> > > I fear that we may have to specify the rules for setting the ToS byte
> > > ourselves, or at least give more guidance on that.
> >
> > I don't see why we'd need to do that. Tunnels, using the same versions or
> > different versions, can cross a region where the DSCP is interpreted
> > differently thus the issues whether to copy the DSCP when encapsulating is
> > identical AFAIK.
> >
> > For the congestion bits the same considerations apply whether the IP versions
> > are the same or different.
> >
> > So do you have a concrete argument that we need explicit text on this?
> > (If we want this to move to DS sooner rather than later I think we should
> > avoid this.)
> 
>         draft-ietf-ipsec-ecn-02.txt (expired) talks about the very issue.
>         it is titled as IPsec-related document, but the consideration applies
>         to any kind of tunnel.
> 
> itojun

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Brian E Carpenter 
Distinguished Engineer, Internet Standards & Technology, IBM 

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