On 11/4/13 9:30 AM, "Wendy Roome" <[email protected]> wrote:
>If the client just discards the both instances of the duplicate CIDR, in >most cases, the endpoint addresses under that CIDR will end up in the >default PID -- the one with 0.0.0.0/0. As a result, the costs to or from >those endpoints are probably useless. This is like saying all IP prefixes that fall under the the default PID are useless which is clearly not the case. There are many prefixes that will map to the default PID that will have a default cost. > >Here's another alternative: if a client detects a duplicate CIDR, the >client removes that CIDR from all PIDs, and adds it to a list of >"duplicate CIDRs". ALTO client should be dead simple. In the very beginning of ALTO protocol Bittorrent folks mentioned that a ALTO client should be able to work by simply downloading a text file from a well known URL/IP address and doing longest prefix matching so that it could be implemented in the simple devices like sensors. This is something I still believe we should strive for. >When the client maps an address to a PID, if the >longest prefix match is a CIDR in the "duplicate" list, then the client >assumes that the ALTO server cannot return a cost to or from that >endpoint. Eg, the cost is unknown. > >A client could easily implement that by creating a PID with an otherwise >invalid name, like "*DUPLICATES*", and moving those CIDRs to that phantom >PID. The ALTO server will never return that PID in a cost map, so to the >client, the costs for those addresses are unknown. > > - Wendy Roome > > >On 11/04/2013 12:06, "Reinaldo Penno (repenno)" <[email protected]> wrote: > >>> >>>I think it does make sense to mandate a client behavior. >>> >>>If we can agree on a specific tie break algorithm, fine. If we agree to >>>say "just ignore the prefix in question but not the whole map", fine. >>>But I think we should agree on something. >>> >>>We shouldn't repeat the good old days of the WWW, where web servers sent >>>special versions of the content to some user agents as workaround for >>>known bugs in these browsers, and user agents pretended to be a >>>different one to get the "right" content ... >> >> >>I do not think this we are comparing apples to apples. >> >>A better comparison is: If a router gets a bad route (say, pointing back >>to its own interface) , does it throw away the entire routing table? >> >>If client throws away the entire map, it has no guidance, falls back to >>regular behavior >>If client disregard only that prefix, it falls back to regular behavior >>for that prefix. > > _______________________________________________ alto mailing list [email protected] https://www.ietf.org/mailman/listinfo/alto
