The overlay networks should behave exactly as the underlay network (in terms of behavior). I think, a TS (or VM) running on overlay network shouldn't know whether it is running on top of some overlay or not. In such a network, if the tenant brings their own virtual appliance(s) to connect multiple VNs (where each VN is an L2 network), they should be able to exchange BGP or other routing protocol messages among those routers. Similarly, if NVE is doing the L3 routing and connecting multiple L2 VNs, it should be able to peer with a tenant owned router. A simple use case is a group of VNs connected via an L3 router and connected via VPN or other service to on-prem network. In this case, if the route changes happen on the on-prem network, using BGP or other routing protocol to propagate the changes to the L3 router on the cloud side would be needed.
On TTL, if we think of NVE as a single logical router, then as the traffic is forwarded between one L2 VN to another L2 VN, the TTL should decrement by 1. The behavior would be exactly the same, if these two VNs were not virtual and connected via a physical router. The behavior would also be the same if these two VNs were virtual but connected via a virtual router running in a VM. This gives consistent behavior to TS in all cases independent of where the router is running (or located). Pankaj > -----Original Message----- > From: nvo3 [mailto:[email protected]] On Behalf Of Dino Farinacci > Sent: Wednesday, November 27, 2013 9:24 AM > To: Xuxiaohu > Cc: Thomas Narten; [email protected] > Subject: Re: [nvo3] 答复: TTL handling in an L3 service > > > IMHO, it makes sense to run BGP among NVEs. In this case, BGP messages > would be transported over the underlay, rather than the overlay. > > What if you wanted the BGP peer to be mobile? ;-) > > Dino > > _______________________________________________ > nvo3 mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/nvo3 _______________________________________________ nvo3 mailing list [email protected] https://www.ietf.org/mailman/listinfo/nvo3
