Thank you, both! ...that kinda sucks, though.
I don't see any rationale in RFC 5308 for why the HELLO packet may only contain the LLA - does anyone know/remember why? (I'm hoping that understanding the rationale will make this an easier pill to swallow.) Obviously this behaviour/requirement is net-new to the IPv6 TLVs, as there's no LLA-cognate in IPv4 (APIPA doesn't count). There is in OSI, I think, but I'm still too sane to read those docs. It makes sense that you would not want LLAs in LSPs, only GUAs, but does that imply that you must​ use either ULAs or GUAs in order to establish IPv6 routes in IS-IS, in an IPv6 environment? That makes about as much sense to me as forcing LLAs for next-hops. -Adam Adam Thompson Consultant, Infrastructure Services [1593169877849] 100 - 135 Innovation Drive Winnipeg, MB, R3T 6A8 (204) 977-6824 or 1-800-430-6404 (MB only) athomp...@merlin.mb.ca<mailto:athomp...@merlin.mb.ca> www.merlin.mb.ca<http://www.merlin.mb.ca/> ________________________________ From: NANOG <nanog-bounces+athompson=merlin.mb...@nanog.org> on behalf of Saku Ytti <s...@ytti.fi> Sent: May 4, 2021 01:44 To: Mark Tinka <mark@tinka.africa> Cc: nanog list <nanog@nanog.org> Subject: Re: IS-IS and IPv6 LLA next-hop - just Arista, or everyone? On Tue, 4 May 2021 at 07:24, Mark Tinka <mark@tinka.africa> wrote: > Junos: >> 2c0f:feb0::1/128 *[IS-IS/18] 02:43:49, metric 5870 > to fe80::1205:caff:fe86:4ac3 via et-4/0/2.0 > to fe80::5287:89ff:fef3:25c3 via et-4/0/2.0 > to fe80::1205:caff:fe86:4b10 via et-5/0/2.0 > > to fe80::5287:89ff:fef3:2610 via et-5/0/2.0 > > IOS XE: > I2 2C0F:FEB0::1/128 [115/6410] > via FE80::1205:CAFF:FE86:4AC3, TenGigabitEthernet1/0/0 > via FE80::1205:CAFF:FE86:4B10, TenGigabitEthernet0/0/0 > via FE80::5287:89FF:FEF3:25C3, TenGigabitEthernet1/0/0 > via FE80::5287:89FF:FEF3:2610, TenGigabitEthernet0/0/0 > > IOS XR: > i L2 2c0f:feb0::1/128 > [115/5870] via fe80::1205:caff:fe86:4b10, 02:45:22, HundredGigE0/3/0/0 > (!) > [115/5810] via fe80::f60f:1bff:feb0:75c4, 02:45:22, HundredGigE0/2/0/1 > SROS: 2001:218:0:1000::1/128 Remote ISIS 48d22h13m 18 fe80::42de:adff:fe98:87e4-"lag1" 25301 ---- https://tools.ietf.org/html/rfc5308 For Hello PDUs, the "Interface Address" TLV MUST contain only the link-local IPv6 addresses assigned to the interface that is sending the Hello. For LSPs, the "Interface Address" TLVs MUST contain only the non-link-local IPv6 addresses assigned to the IS. ---- These are hello derived: A:y...@a04.chcgil09.us.bb# show router isis adjacency r22.chcgil09.us.bb-re0 detail |match Neigh IPv6 Neighbor : fe80::42de:adff:fe98:87e4 IPv4 Neighbor : 129.250.3.205 Vendors do not have the option to use GUA while being RFC5308 compliant. -- ++ytti