AS286 selective destination/dummy CoS
THIS IS AN EXPERIMENTAL FEATURE
v20171023

Fading away ...

AS286/KPN International was taken over by AS3257/GTT in December 2019. AS286 will be integrated into / migrated to 3257 and fade away. Therefore some of the information found on these pages might be outdated / obsolete.

Standard introduction

This document only applies to the KPN International IP backbone AS286.

Selective destination CoS (transit customers only - if at all)

With standard blackholing or selective blackholing you ask AS286 to discard the traffic towards tagged prefix (mostly to mitigate some attacks and to prevent your uplink from AS286 to be overloaded and other traffic suffer from the overload).
This works and is well known, but by doing so, you hardly have a chance to see if the situation changed or to do some further analysis (to get better filters in place).

rtsdCoS (remote triggered selective destination CoS) might be a good alternative. Rather than having AS286 discard the traffic, traffic towards marked (community-tagged) prefixes will be handled with a lower priority (NE = no effort) than the normal traffic (which is BE = best effort). In case your uplink from AS286 will become overloaded, NE traffic will be dropped first (or even rate-limited).

For some more information see the talk given on DENOG8, 2016-OCT-23 (slides (PDF), video).

The default setup is to use 94 percent for BE (non-marked, normal) traffic, 5 percent for NC (network control) and 1 percent (scavenger class) for NE (rtsdCoS marked) traffic. Unused bandwidth will be equally assigned to other traffic requiring more bandwidth. Thus NE traffic can fill a link ... but will be dropped in favor of BE and NC first (unless those request more bandwidth than available ...).
NE traffic will have as DSCP codepoint CS0 set, BE CS1 and NC CS7 ... yes, slightly unusual.
On request we are open to implement also a customer specific rate-limited NE class (e.g. to #nnn Mbit/s) or set DSCP to something you want.

Notes:

rtsdCoS - trigger (transit customers only)

You must at least tag your prefix with one of the following triggers. If not, your announcement will be just treated like every other BE traffic.

(Just to document 286:5556, which will show up on rtsdCoS announced routes: 286:5556 is "all except PE"; 286:555[1-4] are just aliases to 286:5556 + NM (no-marking) whatever is needed.)

rtsdCoS - selective marking (nor non-marking) (transit customers only)

Attach one or more of the following communities to NOT mark (=NM, no-marking) traffic to the NE class on PEs in PoPs, cities countries and continents, which would otherwise mark traffic based on your chosen trigger.
Or explicitly select PoPs where you want traffic to be marked as NE traffic (=SM, selective marking).
Again: NM takes precendence over SM!