[ovs-discuss] BGP EVPN support

[Krzysztof Klimonda]

On Tue, Mar 16, 2021, at 19:15, Mark Gray wrote:
> On 16/03/2021 15:41, Krzysztof Klimonda wrote:
> > Yes, that seems to be prerequisite (or one of prerequisites) for keeping current DPDK / offload capabilities, as far as I understand. By Proxy ARP/NDP I think you mean responding to ARP and NDP on behalf of the system where FRR is running?  
> > 
> > As for whether to go ovn-kubernetes way and try to implement it with existing primitives, or add BGP support directly into OVN, I feel like this should be a core feature of OVN itself and not something that could be built on top of it by a careful placement of logical switches, routers and ports. This would also help with management (you would configure new BGP connection by modifying northbound DB) and simplify troubleshooting in case something is not working as expected.
> > 
> 
> There would be quite a lot of effort to implement BGP support directly
> into OVN as per all the relevant BGP RPCs .. and the effort to maintain.
> Another option might be to make FRR Openflow-aware and enabling it to
> program Openflow flows directly into an OVN bridge much like it does
> into the kernel today. FRR does provide some flexibility to extend like
> that through the use of something like FPM
> (http://docs.frrouting.org/projects/dev-guide/en/latest/fpm.html)

Indeed, when I wrote "adding BGP support directly to OVN" I didn't really mean implementing BGP protocol directly in OVN, but rather implementing integration with FRR directly in OVN, and not by reusing existing resources. Making ovn-controller into fully fledged BGP peer seems.. like a nice expansion of the initial idea, assuming that the protocol could be offloaded to some library, but it's probably not a hard requirement for the initial implementation, as long as OVS can be programmed to deliver BGP traffic to FRR.

When you write that FRR would program flows on OVS bridge, do you have something specific in mind? I thought the discussion so far was mostly one way BGP announcement with FRR "simply" announcing specific prefixes from the chassis nodes. Do you have something more in mind, like programming routes received from BGP router into OVN?

-- 
  Krzysztof Klimonda
  kklimonda at syntaxhighlighted.com