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Re: TOS copying considered harmful
Henry Spencer wrote:
>
> On Fri, 15 Sep 2000, Joe Touch wrote:
> > RFC2003 specifies that the TOS bit is copied from the inner header.
>
> RFC 2003 is a different standard with different priorities. Note that
> RFC 2401 is quite careful to say that IPsec tunneling is "modeled after"
> 2003 tunneling, not that it *is* 2003 tunneling.
OK, then I'll restate.
Don't invent a new mechanism for which an existing system
is already proposed, EXCEPT where necessary.
At the least, the differences should be highlighted,
and the reasons for the differences described and justified.
It isn't clear there is the need for a separate system here.
> > - synchronize these modifications with existing specs
> > (get an update to 2003 in the works)
>
> Why is an update to 2003 required? 2003 remains perfectly satisfactory
> for the purposes it was intended for, security not being one of them.
Tunneling is tunneling. If there is a reason for allowing the DF
bit to be cleared, or for using different TOS bits in IPSEC, there
may be equivalent reasons for allowing them in 2003. If there
are reasons they are prohibited in 2003, then those reasons should
be addressed in any new mechanisms.
Having two specifications for packets with protocol type 4 inside IP
should be avoided if at all possible.
Joe
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