Hi Wei, This draft presents a peculiar way of bringing something similar to bridge-domain/bridge-table concepts into IP-VRFs..
One significant problem, in my opinion, is that you not only introduce a new dataplane dependency; but also propose to _redefine_ VXLAN-GPE header semantics (instead of just using it, or GENEVE). I would assume you have to go to nvo3 WG for the proposed VXLAN-GPE format changes (either with the full draft or splitting it into 2 parts (control & data plane)). Additionally, I would like to see more text on the motivation of the proposed solution. In the abstract you make a point that “This draft … proposes a new solution which can simplify the deployment of layer-3 accessible EVPN service.” -> this simplicity is not obvious at all, and one may argue that this solution is more complex compared to the existing ones (such as draft inter-subnet-forwarding with multiple IP-VRFs) -- Sergey From: BESS <[email protected]> On Behalf Of Wei Wang Sent: Friday, March 12, 2021 12:14 AM To: linda.dunbar <[email protected]>; jorge.rabadan <[email protected]> Cc: bess <[email protected]> Subject: [bess] About draft-wang-bess-l3-accessible-evpn Hi Linda and Jorge, Thanks for your comments at IETF110 meeting, and I think I need to explain our considerations for the newly defined LSI (Logical Session Identifier) concept. Question 1, from Linda Dunbar, "Is the usage of LSI same as the RD for VPN route distinguish?" Answer: LSI(Logical Session Identifier) is mainly used for distinguishing the different logical sessions between CE and PE device. Such session can be established via Vxlan, IPsec, or other tunnel technologies that can span layer 3 network. The LSI information should be transferred via the control plane and forwarding plane. In control plane, we try to use Ethernet Tag ID/newly defined ESI type to transfer, its purpose is to further distinguish the cusomer routes within one provider VRF. In forwarding plane, this information should be inserted into some place of the exising VxLAN encoding, as proposed in our draft:https://datatracker.ietf.org/doc/html/draft-wang-bess-l3-accessible-evpn-04#section-6.1 Question 2, from Jorge Rabadan. "The ESI shouldn't be used to distinguish the route-type 5, it is mainly used for multi-homing purpose" Answer: Currently, we are considering using two methods to identify the routes that associated different LSI: Method 1: Ethernet Tag ID, which is similar with its usage in layer 2 vlan environment. Method 2: Newly defined ESI type(type 6) We think both methods are approachable: Method 1 requires also the update of https://tools.ietf.org/html/draft-ietf-bess-evpn-prefix-advertisement-11(Ethernet Tag ID is set to 0 for route type 5), may arises some confuse with its original defintion. Method 2 requires the extension of ESI type (as described in: https://datatracker.ietf.org/doc/html/draft-wang-bess-l3-accessible-evpn-04#section-6.2). The original purpose of ESI (mulit-homing) can also be preserved. I hope the above explanations help. Comments and questions are always welcome. Best Regards, Wei China Telecom
_______________________________________________ BESS mailing list [email protected] https://www.ietf.org/mailman/listinfo/bess
