On 5/25/2005 7:08 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.
Long ugly history here that I will try to avoid.
IP is end-to-end and you aren't supposed to muck with the packets that are
sent by your customers (or worse, sent by *their* customers). You don't
know what the bits mean to their applications (unless you are one of the
end-points of course) and screwing around with that stuff is a good way to
make people very angry. They're not your packets--leave them alone unless
you are being paid to do otherwise.
While it's true that IP is end-to-end, are fields such as TOS and DSCP
meant to be end to end? A case could be argued that they are used by the
actual forwarding devices on route in order to make QoS or even routing
decisions, and that the end devices shouldn't actually rely on the values
of these fields?
