Hi Suresh, Please see two comments below:
Suresh Krishnan wrote: > > Hi Shree, > Thanks for the comments. Please find responses inline. > > On 10-09-07 09:38 AM, JOSHI, SHRINIVAS ASHOK (SHRINIVAS ASHOK) wrote: > > Suresh, > > > > One of the main challenge in implementing the model proposed by the > > draft is that edge router has no reliable indication if a host (once it has > > sent an RS) is present on the network or not. I agree that this is the main challenge. [...] > > 1. Prefix Lifetime Binding/Expiry.. > > > > Unlike DHCP there is no mechanism with SLAAC for a host (client) > > to renew its address/prefix binding. Relying on host to send a router > > solicitation (as a keep alive) toward edge router is not a viable option. > > > > RFC 4861 (section 6.3.7 ) > > > > Router solicitation "may" be sent after following events > > > > - The interface is initialized at system startup time. > > - The interface is reinitialized after a temporary interface > > failure or after being temporarily disabled by system > > management. > > - The system changes from being a router to being a host, by > > having its IP forwarding capability turned off by system > > management. > > - The host attaches to a link for the first time. > > - The host re-attaches to a link after being detached for some > > time. > > > > In such an situation what is the mechanism for edge router to > > time out a binding from its database ? > > Right. The BBF deployment will have periodic RAs sent to the client > with the PIOs after the initial RS is sent. The client does not need to > periodically retransmit the RSs. Sending periodic RAs with the PIO does not help with the two problems that were pointed out: - the network does not necessarily know when a host attaches, because the host may timeout sending RSs before the link layer is available to carry these RS's up to the node assigning a prefix. As a result the network does not know that a host attached, does not allocate a prefix, and cannot send a periodic RA that contains the PIO necessary for that hosts to complete SLAAC. The hosts ends up with no connectivity. - the network never knows when a host detaches, because the host does not send a "goodbye" RS. As a result, if a prefix were allocated by the network for the host, it cannot be returned to a free prefix pool based on signaling from the host. Are you planning to collect unused prefix based on an unused timer? --julien -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
