Subject: [spring] A note on CRH and on going testing

From: Andrew Alston <[email-masked]>
Date: Thu, 19 Sep 2019 09:49:23 +0000

Hi Guys,

I thought this may be of interest in light of discussions around deployments and running code - because one of the things we've been testing is inter-domain traffic steering with CRH on both our DPDK implementation and another implementation.

So - the setup we used last night:

6 systems in a lab - one of which linked to the open internet.  Call these S1 -> S6
3 systems in a lab on the other side of the world - no peering between the networks in question.  Call these R1 -> R3

We applied a SID list on S1, that steered S1 -> S2 -> S3 -> S6 -> R1 -> R3, with the relevant mappings from the CRH SID's to the underlying addressing (S2 had a mapping for the SID for S3, S3 had a mapping for the SID corresponding to S6, S6 had a mapping for the SID corresponding to R1 etc)

Then we sent some packets - and the test was entirely successful.  

What this effectively means is that if two providers agree to share the SID mappings - it is possible to steer across one network, out over an open path, and across a remote network.  Obviously this relies on the fact that EH's aren't being dropped by intermediate providers, but this isn't something we're seeing.

Combine this with the BGP signaling draft - and the SID's can then be signaled between the providers - work still going on with regards to this for testing purposes.  Just as a note - there would be no requirement to share the full SID mapping or topologies when doing this with BGP - the requirement would be only to share the relevant SID's necessary for the steering. 

I can say from our side - with various other providers - this is something that we see *immense* use case for - for a whole host of reasons.

Thanks

Andrew