Jinmei, The link-local groups in IPv4 do not use IGMP, and the IGMP snooping switches take this into consideration, for the most part - those that don't consider it don't work. Those link-local addresses are things like OSPF Hellos and RIPv2 updates.
Are you suggesting that MLD become part of the minimum requirements because of as yet unavailable MLD snooping switches? Those switches could check the scope of the IPv6 destination and forward all link-local scope multicast to all ports of the subnet - it is at a fixed offset forever and always. Unless we really expect heavy traffic use of link-local scope multicast, using this as the reason for mandating MLD as a minimum requirement is more of an obstacle than an aid for IPv6, in my opinion. Cyndi -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] Sent: Friday, November 16, 2001 10:56 PM To: [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Subject: a short comment on draft-okabe-ipv6-lcna-minreq-00.txt (I think the ipng ML is the best place to discuss the issue, but please correct me if this is not appropriate.) I've taken a quick look at draft-okabe-ipv6-lcna-minreq-00.txt and have a short comment (or a question). The draft says 2.3 Multicast Multicast is not treated in this draft, and it is the candidate for further study (RFC 2375[8], RFC 2710[9]). However, the multicast related to neighbor discovery is considered. So the minimum implementation must join some multicast groups for neighbor discovery (e.g. solicited node groups). This means the implementation should perhaps support MLD, because there will be L2 switches that filter multicast packets unless the switches hear MLD reports for the multicast group. This will even be the case for link-local groups, as in IPv4 multicasts. Since MLD needs a hop-by-hop router alert option, the implementation should support the hop-by-hop options header as a consequence. However, this draft also says 3.1.1 Hop-by-Hop Options Header [Sending] Following 3.1, minimum hosts do not send packets with this extension header. This seems to contradict with the fact above. I think the draft should clarify this point. JINMEI, Tatuya Communication Platform Lab. Corporate R&D Center, Toshiba Corp. [EMAIL PROTECTED] -------------------------------------------------------------------- IETF IPng Working Group Mailing List IPng Home Page: http://playground.sun.com/ipng FTP archive: ftp://playground.sun.com/pub/ipng Direct all administrative requests to [EMAIL PROTECTED] -------------------------------------------------------------------- -------------------------------------------------------------------- IETF IPng Working Group Mailing List IPng Home Page: http://playground.sun.com/ipng FTP archive: ftp://playground.sun.com/pub/ipng Direct all administrative requests to [EMAIL PROTECTED] --------------------------------------------------------------------
