Hi Joel, > I don't think those are the only two alternatives. For > example, something like the APT idea where the full mappings > are shipped to a set of devices such that such a full set is > near to and on the query path of any leaf is an alternative > worth examining.
That's just the basic idea of VA (Virtual Aggregation, see http://tools.ietf.org/html/draft-francis-idr-intra-va-01, and http://tools.ietf.org/html/draft-xu-idr-tunnel-00). And we are now doing some updates to simplify VA mechanism and will submit new versions soon. > From a design perspective therefore, I would tend to look > for a system where a device can be sent unsolicited mappings, > can choose to keep them, and can issue a query via an overlay > to resolve mappings it does not have. In VA, the mappings (EID prefixes associated with RLOCs)are advertised through currrent BGP connections. The RLOC information can be carried by a new BGP attribute, e.g. a special extended community. VA routers will install the mappings selectively into their routing tables according to whether or not they are the APRs(Aggregate Point Router) for those mappings. In this way, the full mappings are distributed among a set of APRs. The overlay composed of a set of APRs can not only be used for mapping request/reponse, but also be used for transferring data packets when the ITR has no mapping entry for these packets in its cache. > While one could argue that this complicates the protocol, it > is an unneeded complication only if we are very sure we know > what the right answer is for information distribution. It is > admittedly more complex than just using BGP to carry EIDs. > Are we sufficiently sure? In VA, extended communities are used for conveying the RLOCs, and BGP computation behavior remain unchanged. So this will not complicate the protocol too much. Xiaohu > Dino Farinacci wrote: > >> Dino - > ... > > The point here is begging a single question: > > > > 1) Should all the mappings in the universe be in an ITR? > > > > 2) Should only the mappings for sites the ITR is > currently talking > > to be in the ITR? > > > > This is the important matter. Decide on that then we can talk about > > how to get the mappings where they need to be. > > > _______________________________________________ > rrg mailing list > [email protected] > http://www.irtf.org/mailman/listinfo/rrg _______________________________________________ rrg mailing list [email protected] http://www.irtf.org/mailman/listinfo/rrg
