What can you use DSCP for?

Tue Oct 30 12:04:52 UTC 2007

On Mon, 29 Oct 2007, John Kristoff wrote:
> How much has really changed?  Do you (or if someone on these big nets
> wants to own up offlist) have pointers to indicate that deployment is
> significantly different now than they were a couple years ago?  Even
> better, perhaps someone can do a preso at a future meeting on their
> recent deployment experience?  I did one a couple years and I haven't
> heard of things improving markedly since then, but then I am still
> recovering from having drunk from that jug of kool-aid.  :-)

Once you get past the religious debates, DSCP can be very useful to
large, complicated networks with many entry and exit points.  Think
about how large networks use tools such as BGP Communities to manage
routing policies across many different types of interconnections. You
may want to consider how networks use similar tools such as DSCP to
mark packets entering networks from internal, external, source address 
validated, management, etc interfaces. There are limited code-points so
you can't be too clever, but even knowing on the other side of then
network that a packet entered the network through a spoofable/non-spoofable
network interface may be very useful.