On Sun, Jun 6, 2010 at 2:15 PM, Tony Li <[email protected]> wrote: > > > Chris, > >>> I believe that Patrick is asking about outbound traffic routing, not >>> inbound. >>> >>> Unfortunately, until we are prepared to make a much larger set of changes, >>> we do not have the tools to allow a host to choose which outbound site >>> connection is used by the hosts outbound traffic. (There are many use cases >>> which would like those capabilities, but we have not found a good way to >>> deliver them.) >> >> I was under the impression that ILNP would permit the site border >> routers to change the locator bits on exit. This means the network >> devices and the hosts have to agree on the set of locators they all >> can use. This also means that the network path betwen host -> border >> has to do some internal TE such that when on exit path is 'bad' >> traffic naturally flows toward an alternate path internally toward a >> 'better' exit path. > > > You are correct, ILNP allows the site border routers to change the locator > on exit. > > However, what Patrick is asking is for something even stronger, which is > outbound exit selection by the host. Most likely, this would imply routing
oh, yuck :) > towards the specific exit based on the packet's source locator in addition > to the destination locator. This is not part of the base ILNP spec as it > exists today. well, does it need to be? If the host puts a src-locator on the packet it creates it's up to the network/host folks to agree to src-route or agree to get overwritten. (Is the 'TE' at the whim of the host or the network? This sounds like shim6 discussions, to me) > >> If the above all works, then the borders simple swap locator bits as >> appropriate on exit... easy, peasy. > > > In Patrick's scenario, swapping is not necessary, as the 'correct' exit has > been selected already. ok. > > In fact, locator swapping is necessary in all OTHER scenarios, as the exit > border router will need to ensure that all packets exiting to a given ISP > have a valid locator for that ISP, to insure that the ISP's RPF or other > filtering succeeds. right, if uRPF is being used, I agree here. (I do hope it IS in use... but not everyone does this) > Regards, > Tony thanks, as always :) -chris _______________________________________________ rrg mailing list [email protected] http://www.irtf.org/mailman/listinfo/rrg
