[AusNOG] DSCP on internet services

[Lincoln Dale]

On 17/02/2010, at 3:42 PM, Raymond, Adam wrote:

> All,
>  
>             I am wandering if other networks modify the DSCP of internet customers when they receive the traffic from the customer (such as resetting it to BE for all traffic). What is seen as being “best practice” for this operation.

DSCP bits have per-link significance only.
you're free to reset them to whatever you want inside your own network.

there is no requirement for them to remain the same end-to-end, that requirement went away when buggy MacTCP 8.1 went away if i recall.

i doubt there is any "best practice" for you to reset/change it to something, but i have seen creative uses where some providers have used it to indicate where traffic was arriving into their network from. e.g. using it as a 'signalling mechanism' for traffic originating via transit provider X, Y or Z or peering point A, B or C because some network vendors' equipment has some platforms that allow one to poll interface counter accounting statistics by precedence bits.


cheers,

lincoln.