Regarding issue 277 of rfc2462bis (Semantics of M/O flags), I want to make a consensus on one thing. (Note: in this particular thread, please just forget the discussion about whether 2462bis should explicitly say the stateful protocol is DHCPv6.)
Previously I proposed to revise section 5.5.2 as follows: > If a link has no routers, a host MAY attempt to use stateful > autoconfiguration to obtain addresses and other configuration > information. > ... > An implementation MAY provide a way to enable the > invocation of stateful autoconfiguration in this case, but the > default SHOULD be disabled. In current RFC2462, the text is "a host MUST attempt to use stateful... An implementation MAY provide a way ... but the default SHOULD be enabled". So, in my proposal, the requirement level was totally reversed. The reason I raised was as follows: >>>>> On Fri, 27 Feb 2004 21:31:57 +0900, >>>>> JINMEI Tatuya <[EMAIL PROTECTED]> said: > To choose appropriate keywords, I'd like to be synchronized with the > node requirements draft (draft-ietf-ipv6-node-requirements-08.txt). > It says in Section 4.5.5 that: > Stateful Address Autoconfiguration MAY be supported. DHCPv6 [RFC- > 3315] is the standard stateful address configuration protocol; see > section 5.3 for DHCPv6 support. > Nodes which do not support Stateful Address Autoconfiguration may be > unable to obtain any IPv6 addresses aside from link-local addresses > when it receives a router advertisement with the 'M' flag (Managed > address configuration) set and which contains no prefixes advertised > for Stateless Address Autoconfiguration (see section 4.5.2). > ... > That is (in my understanding), implementing DHCPv6 is basically > optional with warnings about the case of not implementing it. I know > this was a controversial issue, but I believe the node-requirements > draft made a reasonable decision in terms of practical and realistic > deployment path while honoring future flexibility. > Another reason for the change is because we can at least use > link-local addresses within a single link without a router. I've not seen many responses to this part, but some people, including Ralph (Droms), agreed on this change in their responses. However, Greg Daley pointed out in Seoul that this change might be dangerous because there may still be a node that can forward packets from hosts but is not sending RAs (I intentionally avoid using the term "router" here, because in this context a "router" should be sending RAs). I've been thinking about this for a while, and my conclusion is that we don't have to worry about the scenario and thus do not have to reconsider the original proposal of mine (at least due to this particular issue). The reason is that the problematic scenario looks very unrealistic. If we want to force stateful configuration, we can simply do that by configuring a node as a "router" sending RAs with the M (and/or) O flags being set. And, as far as I know, all existing commercial "packet forwarders" (again, I intentionally avoid the term "router") has the ability to send RAs, and I'm quite sure that future products will. The administrator might want to skip configuring RAs by relying on the RFC2462 default, but it's very likely that this person will still have to configure a DHCPv6 server and the "forwarders" for routing protocols. Also, since there is no other defined way than the stateless autoconfiguration to configure a default router for hosts (note that DHCPv6 does not have an option for this, not as far as I know), we'll have to configure the default route on each host manually. That said, I really do not see any sane reason for relying on the default behavior. Now I want to ask: am I still miss something, or can we agree on the original proposal? JINMEI, Tatuya Communication Platform Lab. Corporate R&D Center, Toshiba Corp. [EMAIL PROTECTED] -------------------------------------------------------------------- IETF IPv6 working group mailing list [EMAIL PROTECTED] Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------