Dean, See my comments in-line.
Igor > As for COPS, its application environment is somewhat similar > to that of PCE but has some problems (if used for PCE applciation) > due to much optimization around its specifics such as: > > 1) The PEP (client) is the one required to initiate the > connection with a PDP (server). Whereas for PCE > application, either PCE (server) or PCC may initiate > the connection. IB>> Why would a PCE want to initiate a connection with a PCC? > > 2) There requires a synchronization between PEP and PDP for > the policy application with states maintained on both places. > For PCE application, the PCE server is only required to > perform a one-time service for each LSP, without the need > maintain any subsequent states. IB>> Even if all this is true, why is it a big deal? > > 3) It requires some work to support a PDP functions as a PEP > and communicates with another PDP. PCEP supports this model > fully. IB>> Functions of PDP and PEP are orthogonal and surely could be physically co-located > > 4) COPS is a server-client protocol, but with code point > heavily dedicated for a specific application. It does not > serve general purpose if any, and to support PCE application, > there would be a large number of extensions, thus defeating > the purpose of reusage. IB>> PCIM is designed to be easily expanded for application (read PCE) specific needs Igor > > As a result, I'd favor PECP as a PCE-specific protocol; it is much > cleaner and also light-weighted. > > Dean > >>-----Original Message----- >>From: [EMAIL PROTECTED] >>[mailto:[EMAIL PROTECTED] On Behalf Of Dean Cheng (dcheng) >>Sent: Monday, October 03, 2005 3:30 PM >>To: Adrian Farrel; [EMAIL PROTECTED] >>Subject: RE: [Pce] Choosing the PCE protocol >> >>Hi, >> >> I don't think HTTP is a good candidate for the PCE application >> and here are some weakness one could think of, if it used for >> PCE application: >> >> 1) The HTTP is specifically designed for communications between >> web server and its client, or applications in that nature. >> Although it is possible to add extensions to support PCE >> application, it would require a considerable amount of work. >> That is not worth of the effort given the much smaller and >> narrower application scope of PCE. >> >> 2) The payload of HTTP messages (both request and response) >> is in form of byte stream, which is unstructured comparing >> to the PCEP proposal, where the content is structured >>with objects. >> For the PCE application, the object based format is more >> efficient in terms of processing. >> >> 3) The HTTP does not have unsolicited messages such as Notification >> message and Error message that are defined by PCEP. >> >> 4) PCE architecture allows a PCE functions as a server but also as >> a client communicating with another PCE server. In both cases, >> the same protocol is used. PCEP supports this scenario. There >> requires some work to make HTTP behavior as such. >> >>Dean >> >>>-----Original Message----- >>>From: [EMAIL PROTECTED] >>>[mailto:[EMAIL PROTECTED] On Behalf Of Adrian Farrel >>>Sent: Thursday, September 29, 2005 7:27 AM >>>To: [EMAIL PROTECTED] >>>Subject: [Pce] Choosing the PCE protocol >>> >>>Hi, >>> >>>Three candidate protocols have been brought to my attention for us to >>>consider. These are (in no specific order): >>>- HTTP >>>- PCECP (as draft-vasseur-pce-pcep-02.txt) >>>- COPS >>> >>>I would like to close the nomination period, and move on to >>select our >>>protocol. >>> >>>The best approach will be if supporters of the candidate protocols >>>indicate (briefly) why their proposed protocol is suitable. It would >>>also be helpful if they were frank about what the weaknesses of their >>>proposal are. >>> >>>And please - this is not an election, it is an interview process. >>> >>>Thanks, >>>Adrian >>> >>>PS The reason why JP is keeping quite on this is that he is an author >>>of draft-vasseur-pce-pcep-02.txt and so (quite rightly) is not >>>occupying the chair during this discussion. >>> >>> >>> >>> >>>_______________________________________________ >>>Pce mailing list >>>[email protected] >>>https://www1.ietf.org/mailman/listinfo/pce >>> >> >>_______________________________________________ >>Pce mailing list >>[email protected] >>https://www1.ietf.org/mailman/listinfo/pce >> > > _______________________________________________ > Pce mailing list > [email protected] > https://www1.ietf.org/mailman/listinfo/pce > > _______________________________________________ Pce mailing list [email protected] https://www1.ietf.org/mailman/listinfo/pce
