Thanks for the RFC historical lessons. --there was historically some assumption that next hop must be of the same AF as prefix. --RFC 2858 says that Next Hop field should match AFI. On the other hand, RFC 4760 says that Next Hop Field should match combination of AFI/SAFI. --authors of RFC 4364 were trying to make it consistent with 4760. --Also, drafts of RFC 4364 and RFC 4760 were being developed practically at the same time period.
The problem is clear, the nexthop field has been inconsistent between different L3VPN/MVPN scenarios and different implementations in the long history. <draft-dawra-bess-srv6-services-00> is the latest draft, but it has different nexthop in section 3.1 to 3.4, in the year 2019. Back to my suggestion: implementation should interpret nexthop RD+IPv4 and nexthop IPv4 the same, and interpret nexthop RD+IPv6 and nexthop IPv6 the same. I think it may be helpful for <draft-dawra-bess-srv6-services-00> to add the above text, and update RFC4364/4659/4760/5549, to eliminate the worries about interoperation. ----is there any worries about interoperation ? Thanks Jingrong From: Alexander Okonnikov [mailto:[email protected]] Sent: Wednesday, June 26, 2019 9:38 PM To: Robert Raszuk <[email protected]> Cc: UTTARO, JAMES <[email protected]>; Xiejingrong <[email protected]>; [email protected]; [email protected]; [email protected]; [email protected]; [email protected] Subject: Re: [Idr] [bess] [Softwires] Regarding the Next Hop Network Address coding for IPv4 VPN over IPv6 Core in RFC5549 Hi Robert, Sorry, I was not so precise :-) Of course, RD part in Next Hop is not copied from RD of NLRI, but zeroed. I was trying to explain why Next Hop field in RFC 4364 and RFC 4659 has format RD:IP (VPNvX address) rather than just IP. Thank you!
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