> > RAs aren't used for reachability we have > > ND/NUD for that.
Once again, NUD (as I understand it, and the way it is defined in 2461) is not based on RS/RA exchanges. It is based on NS/NA exchanges. Thus, I do not at all understand the rest of your note. Further, based on what you wrote below, I think you should start by defining the problem statement - what it is you are trying to solve. Your combination of messages sent via a paging channel and one (and apparently only one message) sent via the normal data channel doesn't implement NUD as I understand it. Finally, why do you care about NUD if the node is in dormant mode? If the node is dormant, having its NUD state kept up-to-date seems like an odd thing to require (especially since NUD state is short-lived, on the order of minutes). > NUD (RS-RA) becomes useless when the host is in dormant mode and > reachable via a paging channel. > To initiate NUD, the host needs to wake up and send RS. The router's > answer (unicast RA) will be received via a traffic channel. It won't be > received via a paging channel, because the host is NOT in dormant mode. > That is, the paging channel is not tested with NUD. > After the NUD procedure, the host will re-enter dormant mode. > But, the host doesn't know if it is reachable. Because the > paging channel wasn't tested. > With unsolicited RAs: > The unsolicited RAs can be received by dormant mode hosts. That is, > they can check the paging channels. Here is the procedure: > 1. Router sends an unsolicited periodic RA to a host. > 2. The host is in dormant mode, therefore the RA triggers > link-layer paging. > 3. Host receives a link-layer paging message via a paging channel, > and wakes up. > 4. Host acquires a traffic channel. > 5. Host receives the unsolicited RA via the traffic channel. > If the host successfully received an unsolicited RA, this means > that the traffic channel and also the paging channel worked > smoothly. Not as I understand it. It only means that the data channel was shown to work in one direction -- NUD explicitely verifies that a channel is working in _both_ directions. Are you assuming that if one can send data via the paging channel, that is good enough to conclude that the data channel also works? Is that a valid assumption? Thomas -------------------------------------------------------------------- IETF IPv6 working group mailing list [email protected] Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
