Bob Hinden <[EMAIL PROTECTED]> writes: > John,
> > For those IPv6 nodes that implement DHCP, those nodes MUST use DHCP > > upon the receipt of a Router Advertisement with the 'M' flag set (see > > section 5.5.3 of RFC2462). In addition, in the absence of a router, > > IPv6 Nodes that implement DHCP MUST attempt to use DHCP. > >to: > > Nodes that implement DHCP MUST use DHCP upon the receipt of a > > Router Advertisement with the 'M' flag set (see section 5.5.3 of > > RFC2462). In addition, in the absence of a router, > > IPv6 Nodes that implement DHCP MUST attempt to use DHCP. In this > > context, 'use DHCP' means trying to obtain both address(es) and > > other configuration information through DHCP. For my tastes, there is too much protocol specification above (use of MUST language). Better to just cite the existing standards. > Please remind me why the "in the absence of a router" text is there. I am > having a hard time thinking about a scenario where there would be a DHCP > server, but no router. The presences of a DHCP relay agent would also need > a router to be useful. Perhaps because folk have forgotten about existing text in 2461 & 2462? :-) >From section RFC 2461 6.3.7: > If a host sends MAX_RTR_SOLICITATIONS solicitations, and receives no > Router Advertisements after having waited MAX_RTR_SOLICITATION_DELAY > seconds after sending the last solicitation, the host concludes that > there are no routers on the link for the purpose of [ADDRCONF]. > However, the host continues to receive and process Router > Advertisements messages in the event that routers appear on the link. RFC 2462, Section 5.5.2 says: > 5.5.2. Absence of Router Advertisements > > If a link has no routers, a host MUST attempt to use stateful > autoconfiguration to obtain addresses and other configuration > information. An implementation MAY provide a way to disable the > invocation of stateful autoconfiguration in this case, but the > default SHOULD be enabled. From the perspective of > autoconfiguration, a link has no routers if no Router Advertisements > are received after having sent a small number of Router Solicitations > as described in [DISCOVERY]. We can debate whether the current text makes sense, but it reflects the thinking at the time... Thomas -------------------------------------------------------------------- IETF IPv6 working group mailing list [EMAIL PROTECTED] Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
