Hello, On Thu, 2006-08-31 at 15:45 -0400, Thomas Narten wrote:
> RAs aren't used for reachability we have > ND/NUD for that. 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. pars -------------------------------------------------------------------- IETF IPv6 working group mailing list [email protected] Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
