Panel from Mark Handley
The data plane is well structured with the different layers of the OSI model. Comparatively, in the control plane, there are a lot of protocols but no structure. These protocols each solve a very specific issue. They do a good job about it but now is the time to take a step back.
The control plane protocols tend to solve three categories of problems:
- congestion control
- traffic engineering
Or problems resulting from the intersection of two of these categories.
In the presentation, Mark focusses on the intersection between congestion control and multi-homing. He proposes multi-path transport (multipath TCP) to solve this issue. For solving the congestion control and TE intersection problem, he proposes the re-ECN solution from BoB Briscoe.
- Pierre Francois: Clarification to the treatment of BGP non-transitive extended communities (draft-decraene-idr-rfc4360-clarification). The implementations tested by the authors do not behave in the same way. One implementation removes the community upon reception on an eBGP session. The authors of the draft highlight that section 6 of RFC 4360 says that non-transitive extended communities SHOULD not be transmitted on eBGP session. Since it is a “SHOULD” and not a “MUST”, the authors suggest that when such a community is received on an eBGP session, it is not stripped from the BGP update. It is important to fix this behavior should BGP graceful shutdown be performed using a non-transitive extended community instead of the current allocated community. Using a non-transitive extended community will simplify the filters that currently need to be configured to confine graceful shutdown to the local ASs.
- Pierre Francois: Analysis of the path selection modes proposed for add-path (draft-vvds-add-paths-analysis). In the “session type” mode (not described in the draft), the ASBRs advertise all paths to their RRs and on iBGP sessions of type “over”. RRs advertise the 2 best paths to their iBGP clients. This mode seems the most interesting to me, if the RRs can manage to hold all the routes.
- Bruno Decraene: Requirements for BGP graceful shutdown (draft-ietf-grow-bgp-graceful-shutdown-requirements). It is important to provide a solution to reduce connectivity/packet losses upon the maintenance of a BGP session. Bruno asked that the draft be last called. After the presentation of the requirements, Pierre presented one solution that does not require modifications to BGP, only configurations of BGP filters. The presentation was followed by operators coming to the mic. They were afraid that the solution be more complex than what they do today. For example, one of them uses AS-path prepending. He does not care about having 0 packet loss. Thus, tunnels are not needed (too expensive). However, he would benefit from the proposal relying on low loc-pref setting. This will ensure that traffic be redirected away from the maintained resources. This is not always the case with AS-path prepending. This is because the AS-path length comes after the loc-pref in the BGP decision process.
Purpose: protocol definition for ISP caching for P2P networks.
Motivation: reduce P2P traffic in the ISP network.
Debate: are solutions like webDAV and NFS not suitable, not sufficient?
Comment: requirements as expressed today are too broad. They leave room to a large number of different solutions.