The technical representatives for the NORDUnet member networks recently had a discussion about what, if anything, we should do with respect to diff-serv in NORDUnet and the member networks. Two points were discussed:

• It would be beneficial to document a common set of diff-serv code points, and they should use the same values that GÉANT uses.
• Whether we should recommend implementation of diff-serv, and where it needs to be done.

GÉANT has agreed on a common set of diff-serv code points (DSCPs) corresponding to the different services. It goes without saying that the normal best effort service has a code point of 0.

Premium IP

Code point 46 (decimal). This service is also known as expedited forwarding. This provides a service with guaranteed capacity, and an upper bound on delay and delay variation between authorized sources and destinations. Do note, though, that traffic which exceeds the guaranteed capacity will be dropped, so it not necessarily an ideal fit for all applications.

Less than best effort (LBE)

Code point 8 (decimal). This is also known as scavenger service, and this traffic can be pushed aside (and dropped) if other traffic classes fill the available capacity.

There is full agreement among NORDUnet and the NORDUnet NRNs that the diff-serv fields in the packets will be passed on unmodified, so that the end user institutions can use the diff-serv fields as they see fit for experimentation among themselves and other users.

Note that if you want to use the Premium IP service of GÉANT and gain any benefit from doing so (i.e. get priority treatment), the session needs to be pre-registered via (currently) manual administrative procedures. Failing to do so will cause the traffic to be re-marked to (in effect) best effort service on entry to the GÉANT network. See the description of Premium IP on Dante's web site for further information. As specified there, any request to use this service must be made via your NRN.

However, when it comes to implementing specific diff-serv based priority handling in our routers, NORDUnet and the NORDUnet NRNs decided that we make no specific recommendation for now.

The current state and plans for diff-serv deployment for NORDUnet and the NORDUnet NRNs is as follows:

NORDUnet

No special queueing based on diff-serv at the moment, and no immediate plans.

FUNET (FI)

Implements the LBE service, and uses it for transporting NetNews. FUNET has decided that they will not implement a premium IP service anytime soon.

SUNET (SE)

No special queueing based on diff-serv at the moment, and will probably not implement diff-serv in the backbone network.

UNINETT (NO)

No special queueing based on diff-serv implemented at the moment. Where UNINETTs customers in theory could benefit from this at the moment, UNINETT has issues with most of the currently deployed hardware which runs out of CPU before a queue is formed, so there would be little benefit in providing a comprehensive diff-serv setup at the moment.

Forskningsnettet (DK)

No special queueing based on diff-serv at the moment, and no immediate plans for such an implementation either. May change with customer demand.

RHnet (IS)

No special queueing based on diff-serv at the moment. No plans to implement in the backbone.

IETF diffserv working group (concluded) with pointers to standards documents and other RFCs.

Dante's document on QoS in GÉANT which also has other pointers.