looking back at the text in S2.2, the reason for using multicast-capable rather than just multicast was that multicast-capable was (i think) supposed to cover both multicast links which have native support and point-to-point links which do multicast degenerately. i think that my problem could be solved by adding a sentence (or separate definition) in 2.2 to say just that i.e.
multicast-capable link - a link which is either point-to-point or multicast type then i think the substitution s/multicast/multicast-capable/ elsewhere works fine. the remark that 'all link types are expected to provide multicast services for IP' really deserves some exploration other than in 2461bis. if this is really a requirement for *all* scopes of multicast service then it is manifestly not being met by most IPv6 implementations. for ND all we need is multicast at the link level. DHCPv6 may need it at the site level. but what should we expect from a general implementation in the way of multicast services? there is really a considerable amount of vagueness about this across all the specifications. Regards, Elwyn -----Original Message----- From: Soliman, Hesham [mailto:[EMAIL PROTECTED] Sent: 26 October 2004 15:39 To: Davies, Elwyn [HAL02:0S00:EXCH] Cc: [EMAIL PROTECTED] Subject: RE: RFC2461bis: Multicast capable vs Multicast Service [was RE: Comments for rc2461bis] Your mail server forgot ;) => Grr! Hate, hate. Using the term 'multicast services' around this area is confusing. If the link MUST provide multicast services maybe that is something that should be in the basic definition of IPv6 (it isn't stated explicitly in RFC2460) rather than in 2461bis. Expanding on what I said originally, one reasonable interpretation of the requirement that all links support multicast services is that they are in some sense 'multicast capable': if you take this view then *all* links are necessarily multicast capable. So I think the problem is that the language doesn't properly convey what I think is the intention: I believe we are trying to distinguish between: - links that provide multicast *as a Layer 2 capability* ('The hardware does multicast') - links that don't, so that the multicast services have to be provided as an overlay => Exactly. I guess our difference is that I get the distinction from the spec when I read it now (with "multicsat capable" replacing "multicsat" in 2.2). Is that a sufficient change ? Let me know if you think another change is needed. Hesham Hope this clarifies my point. Regards, Elwyn Original Message ================ S2.2 and S3: The note after the NBMA definition says that '...all link types (including NBMA) are expected to provide multicast service for IP...'. A naive interpretation of the phrase in S3 'On multicast-capable links...' (just after the Redirect bullet) in conjunction with the previous note might take it that actually all links are multicast-capable. The term should be explicitly defined so as to explicitly exclude NBMA and any other sort of links that this phrase is not supposed to apply to - or to allow it to be done optionally on this sort of link - the current wordings are too vague. This is also related to the comment on 6.2.1 below. => I'm not sure I see the problem you see (and I looked at the 2462 thread). We can make the link definition for multicast, a definition for "multicast capable". But apart from that the current spec states refers to other docs in the introduction when it discusses NBMA links. The text you refer to above is talking about multicast services, which is a different issue. So for now, I'll s/multicast/multicast capable in 2.2 and that should do the job IMO. ---------------------------------------------------------------------------- ------ Elwyn B Davies Routing and Addressing Strategy Prime & IPv6 Core Team Leader CTO Office, Portfolio Integration Solutions Ready Nortel Networks plc Email: [EMAIL PROTECTED] Harlow Laboratories ESN 6-742-5498 London Road, Harlow, Direct Line +44-1279-405498 Essex, CM17 9NA, UK Fax +44-1279-402047 Registered Office: Maidenhead Office Park, Westacott Way, Company No. 3937799 Maidenhead, Berkshire, SSL6 3QH ---------------------------------------------------------------------------- This message may contain information proprietary to Nortel Networks plc so any unauthorised disclosure, copying or distribution of its contents is strictly prohibited. ---------------------------------------------------------------------------- "The Folly is mostly mine" and the opinions are mine and not those of my employer. ============================================================================ ====== ======================================================== This email may contain confidential and privileged material for the sole use of the intended recipient. Any review or distribution by others is strictly prohibited. If you are not the intended recipient please contact the sender and delete all copies. ======================================================== -------------------------------------------------------------------- IETF IPv6 working group mailing list [EMAIL PROTECTED] Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
