Comment 7 for bug 1905295

Revision history for this message
Akihiro Motoki (amotoki) wrote :

I think we need to clarify the problem this RFE would like to address.

The current problem description mentions ECMP between R1/R2 (neutron logical router) and R3/R4 (provider router) but the proposed change just discusses multiple external gateways per neutron router. I think it solves a case like below. Is my understanding correct?

 R3 R4
  |X|
   R1
  /|\
  CCC

I also have more questions. I am not sure they are part of this RFE.
- How is ECMP configured? To make it work, ECMP needs to be configured in VMs, neutron routers and provider routers. Perhaps some routing protocol is needed.
- How about NAT and floating IP? If we don't consider active-active case for R1/R2 and only consider multiple external gateways, NAT and floating IP might work.

Regarding NAT (SNAT and floating IP), as Brian said, a neutron router does not do NAT when an external and internal networks belong to a same address scope. This mechanism is used for IPv6 networking and it also works for IPv4 network.