Meeting Minutes: June 21, 2018

Meeting Time and Location

10 am to 11:30 am PDT (GMT - 7), Barefoot Networks, 4750 Patrick Henry Dr, Santa Clara, CA 95054

Attendees

Barefoot Networks: Jeongkeun Lee, Mickey Spiegel
Ciena: Peng He
Cisco Systems:  Mario Baldi, Ramesh Sivakolundu
Intel: Michael Orr
IXIA: Chris Sommers
Mellanox: Barak Gafni
Netsia: Jeffrey Van
UFRGS: Jonatas Marques
VMware: Mukesh Hira

Communicating INT Metadata Semantics

Mickey Spiegel presented his pull request - a Yang model for defining semantics of INT metadata supported by an INT switch. The proposed model can be found here. This is a great start and covers a lot of metadata currently exported by INT switches. Once this initial version is committed, working group members are encouraged to build on this and add further support as necessary. Some open issues with the current proposal that were raised at the working group meeting are -

• Proposal does not support different semantics across line cards in a chassis-based INT switch. Actually, the INT header format only include a switch ID, there is no identifier at a lower granularity than the switch, so there is no way to know which line card exported the metadata. This is am important aspect to be addressed overall in the INT framework. There were some discussions on each line card being an INT switch by itself, but that will require internal chassis and backplane definitions to be exposed to the INT monitor
• Should the model cover one-way communication from switch to monitor, or should this be a bidirectional model. For example, switch reports different units of metadata that it can support equally efficiently and INT monitor chooses the units it would like to use.
• With respect to a communication channel, let us discuss with P4 API working group and Stratum project to see if any of their components can be leveraged. For this, it would be good to come up with an overview picture/slide of INT architecture and components to set context.

Domain-specific INT metadata

Ramesh Sivakolundu from Cisco Systems presented a proposal to allow for instructions and metadata that are not defined in the P4.org INT specification, on a per-domain basis. As long as all INT switches in a domain support this set of metadata, INT may be used to gather this metadata (even if individual switches are from different vendors who have worked together for interoperability).

Ramesh's slides are available here. Pull request is here

Next Steps

• If you have comments/concerns on the two items discussed at the meeting, please post comments on the pull request on GitHub.
• Next working group meeting will tentatively be on July 5, 2018. Agenda and location to be announced closer to the date. One potential agenda item for the next meeting is using IPv6 hop-by-hop header to carry INT metadata, Cisco would like to explore this.