Thank you so much, so if I understand correctly, when A sends an Update to B, B needs to know address of A and, according to the proper circumstances, B gets address of A either from IPv6 packet's source address (case 1) or from The Next-hop TLV sent on purpose by A (case 2).
Considering the following scenario x y z w A ------- B ------- C with B that has, in its routing table, an entry for prefix of C with next-hop set to w. I would like that by announcing this route, B includes the fact that its selected next-hop is w. So that receiving an "enriched" Update from B for <Prefix of C, NH=w>, a neighbor node is able to check if it is the selected next-hop (e.g. A will fail, because x==w->false, while C will succeed w==w->true). If I understand correctly what I would call my "next-hop" TLV has a different meaning from the RFC one, therefore I should put the info I need into a subtlv right? Thank you and best regards Lorenzo 2016-12-06 17:43 GMT+01:00 Juliusz Chroboczek <j...@irif.fr>: > > I do not understand the meaning of "next-hop" TLV for a subsequent > Update. > [...] > > What should I do put the route's next-hop into update messages? > > 1. For an IPv6 route, do not send a Next Hop TLV. In its absence, the > receiver will derive the next hop address from the IPv6 packet's source > address. > > α β > A ------- B > > Node A has IPv6 address α. It sends an Update to B in an IPv6 address > with source address α. B uses α as the route's next hop. > > 2. For an IPv4 route, precede the Update with a Next Hop TLV with the > on-link address of the sending node. The receiver will use this > address as the route's next-hop. > > α β > A ------- B > ℵ ℶ > > Node A has IPv6 address α and IPv4 address ℵ (that's "aleph"). It > sends an IPv4 Update to B, with source address α. Since the route > requires an IPv4 next hop, B needs to learn ℵ somehow — so it consults > the preceding Next Hop packet, which contains ℵ. > > — Juliusz > > >
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