2013-01-30 16:52, Tom Taylor <[email protected]> : > On 30/01/2013 9:56 AM, Rémi Després wrote: >> >> Le 2013-01-30 13:47, Ole Troan <[email protected]> : >> >>> Tom, >>> >>> [...] >>> >>> > [Ole said:] >>> I'm fine with fixing a to 4. >>> if an end user needs well known ports, give her a full address. >> > [Rémi said:] >> An alternative is possible that >> - permits ISPs that want it to assign well-known ports to some privileged >> users without necessarily giving them full IPv4 addresses; >> - uses a trivially simple algorithm. >> >> That which has been chosen for 4rd can be used for MAP-E as well. It uses >> for this an option to be used if well-nown ports must be assignable. >> >> It is specified in two sentences, in >> http://tools.ietf.org/html/draft-ietf-softwire-4rd-04#page-15, at the end of >> the first paragraph. >> Its complete picture representation is in a part of Figure 5: >> >> (by default) (If WKPs authorized) >> : : : : >> +---+----+---------+ +----+-------------+ >> Ports in |> 0|PSID|any value| OR |PSID| any value | >> the CE port set +---+----+---------+ +----+-------------+ >> : 4 : 12 : : 16 : >> > ... > > OK, this explains the bit about system ports in the text, when a = 0. The one > objection I see to that is again the matter of address dependency -- the > system ports are available only for the first few PSIDs, the PSIDs appear as > part of the MAP endpoint prefix, so the prefix value becomes constrained. > > Since devices requiring system ports are likely to be servers, the full > address solution makes sense on another level too.
Agreed, it does make sense, and I believe that many ISPs may make this choice. (I personally argued in this direction long ago.) But there has been a firm requirement in the WG that, even for shared addresses, one of the CE could have the well-known ports. The WKPs-authorized option has been added to 4rd to satisfy this requirement. I don't think this requirement has disappeared. A copy of this mail is addressed to Maoke who was involved in this discussion. Regards, RD > > Tom Taylor _______________________________________________ Softwires mailing list [email protected] https://www.ietf.org/mailman/listinfo/softwires
