Woj et al, > Perhaps a basic question or two: What is the purpose of the ULA being > advertised on the shared segment, and is the intent for the "2nd router" > to auto-config itself an address in the ULA space and begin advertising > that ULA too?
the purpose of the ULA is to provide stable addressing and allow local traffic to continue. in the case where a global address hasn't yet been provisioned or e.g it's lease has timed out. the requirements around two routers, is to avoid multiple ULA prefixes on the link. I certainly don't expect a router to first configure it's interface from another router's RA to then advertise that prefix out in an RA on that interface. > Also, what is the proposed way of dealing with the case where the "2nd > router" stops hearing advertisements from the 1st router? There are some > interesting failure scenarios here, which may call for a more elaborate > router-router discovery protocol, eg VRRP. indeed. the reason for me asking the question was: - are these requirements violating any RFC? - as this behaviour is not covered in existing IPv6 RFCs are they clear enough for implementors to implement? - are these requirements sufficient to solve the whole problem? - do we need any IETF work to cover these 'gaps'? - is this a problem which should be solved? cheers, Ole >> -----Original Message----- >> From: [email protected] [mailto:[email protected]] On >> Behalf Of Ole Troan >> Sent: 12 January 2010 18:51 >> To: [email protected] >> Subject: Question: Detecting routers on a link >> >> hi, >> >> a question arose from work I'm doing with the BBF and their >> CPE requirements document (TR-124/WT-192). an issue has been >> raised with regards to a requirement about CPE routers >> automatically offering ULA addresses on the LAN. in the case >> of multiple CPE routers on a link, the suggestion is the >> following two requirements: >> >> LAN.ADDRESSv6. 3 The device MUST send a Router >> Solicitation to the LAN, to determine if there >> are other >> routers present. MUST >> LAN.ADDRESSv6. 4 If the device determines other >> routers are present in the LAN, and that another >> router is >> advertising a ULA prefix, the device MUST be configurable to >> automatically >> use this information to decide not to advertise its own >> ULA prefix. MUST >> >> any opinion on these requirements and how they compare with >> expected behavour as specified in RFC4861? >> >> cheers, >> Ole >> -------------------------------------------------------------------- >> IETF IPv6 working group mailing list >> [email protected] >> Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 >> -------------------------------------------------------------------- >> -------------------------------------------------------------------- IETF IPv6 working group mailing list [email protected] Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
