BCP regarding TOS transparancy for internet traffic

Wed May 25 18:16:45 UTC 2005

RFC 2474 permits the DSCP to be over-written on ingress to a network. 
RFC 3168 gives rules for over-writing the ECN flags.

US NCS currently has a filing before the FCC (unless FCC has recently 
responded) asking for a DSCP value that would be set only by 
NCS-authorized users, never over-written, and that ISPs would either 
ignore or observe in order to give that traffic preferential service. 
Yes, I have made my comments about that too.

I guess the question is why, just because you don't want to offer a 
specific service, you want to prevent other ISPs from offering a stated 
service to a user? There are some fairly good-sized ISPs offering 
services based on the TOS octet. Are you trying to drive users to them? 
Any customer that is setting EF on VoIP service is certainly expecting 
that to go end to end.

On May 25, 2005, at 4:08 AM, Mikael Abrahamsson wrote:
> I've been debating whether the TOS header information must be left 
> untouched by an ISP, or if it's ok to zero/(or modify) it for internet 
> traffic. Does anyone know of a BCP that touches on this?
>
> My thoughts was otherwise to zero TOS information incoming on IXes, 
> transits and incoming from customers, question is if customers expect 
> this to be transparent or not.
>
> Reading 
> <http://www.sanog.org/resources/sanog4-kaulgud-qos-tutorial.pdf> it 
> looks like in the Diffserv terminology, it's ok to do whatever one 
> would want.
>
> Any feedback appreciated.
>
> -- 
> Mikael Abrahamsson    email: swmike at swm.pp.se
>