I am surprised by your tone. I am touching the tech points and trying to clarity why PCE cannot *determine* those parameters. You can correct me if I am wrong from the tech perspective.
If you still use this kind of tone, sorry, I will ignore your response. Best Regards Fatai 发件人: Edward Crabbe [mailto:[email protected]] 发送时间: 2012年11月12日 11:59 收件人: Fatai Zhang 抄送: Jan Medved (jmedved); [email protected] 主题: Re: [Pce] 答复: Questions about stateful PCE, relation to WG charter and opinion about stateful PCE We currently appear to be involved in some sort of pre-fiat working group process debate. Unfortunately, I think you're injecting a particularly onerous and unnecessary sort of wg bureaucracy here, and for no discernible reason. At this point, given the lack of any substantive technical argument, I have to say that I actually feel that you're being a bit obstructionist. :-/ I hope that's not the case. Obviously the working group can have any technical discussion it wants, to within the bounds of reason and the chair's limits of tolerence. ;) So let's do that, and try to make our time together here productive. ^_^ w/r/t the specific comments: Yes, we already have introduced a delegation function and have had since the first rev of the draft. It is, IMO, defined clearly in the draft-crabbe-pce-stateful-pce-02. You should read it. If you don't think the definition is clear, then we should discuss that so we can improve the text. I continue to maintain that the main differences between receipt of computation results between 5440 and active PCEP as defined in draft-crabbe-pce-stateful-pce-02 is directionality and asynchrony. If you have a good reason for thinking that this is not the case, or have other technical issues with the delegation model, then please, by all means... On Sun, Nov 11, 2012 at 6:56 PM, Fatai Zhang <[email protected]<mailto:[email protected]>> wrote: Hi Jan, You said: =>By requesting a path computation from a PCE, the PCC gives the PCE authority to determine the ERO, LSP Bandwidth, protection, LSP setup and hold priorities, etc. The PCE is the entity that determines these parameters - would you agree? [Fatai] Sorry, I don’t agree. The parameters (LSP bandwidth, protection, etc) are the constraints sent from PCC to PCE for *path computation*. For example, a PCC sends a PCReq to request a LSP with bandwidth 1Gpbs, and then the PCE MUST not return a path with e.g, 100Mbps, ie., the PCE *cannot determine* these parameters. The ERO is the path information (path list) that PCE returns to PCC after path computation. If you want to introduce *delegation* function (whatever we call it), the delegation definintion should be defined clearly. And then the WG will/can discuss more whether this “delegation” is needed or not (and whether this “delegation” is in the scope of the existing charter). Best Regards Fatai 发件人: Jan Medved (jmedved) [mailto:[email protected]<mailto:[email protected]>] 发送时间: 2012年11月10日 0:27 收件人: Fatai Zhang 抄送: Oscar González de Dios; [email protected]<mailto:[email protected]> 主题: Re: [Pce] Questions about stateful PCE, relation to WG charter and opinion about stateful PCE Faital, On Nov 9, 2012, at 12:20 AM, Fatai Zhang wrote: >The delegation of LSP control to a PCE is *implicit* in RFC4655. When a PCC >sends a PCReq message to a PCE requesting path computation (and parameter >setting) for an LSP, it effectively > delegates control over that LSP to the PCE. The delegation is valid for one > request (and one path computation) only. [Fatai] I don't think that RFC4655 can support delegation of LSP *control* (even implicitly). A PCC sends a PCReq to a PCE, it does not mean that this LSP is delegated to the PCE. By requesting a path computation from a PCE, the PCC gives the PCE authority to determine the ERO, LSP Bandwidth, protection, LSP setup and hold priorities, etc. The PCE is the entity that determines these parameters - would you agree? Now, whether we use "control", "authority", "power", "mandate", whatever - that does not change the fact that the PCC asks the PCC to determine what the LSP parameters are, and the PCE determines what the LSP parameters are. That's what we call delegation - the PCC "delegates" the computation of LSP path and determination of LSP parameters to the PCE. My email states a little later: "the PCC may or may not use the LSP path/parameters that it got from the PCE". We all agree that the PCC has the ultimate control over the LSP - it may take the directions from the PCE, it may not. draft-ietf-pce-stateful-pce does not change any of this. The PCC gives the PCE the control/authority/mandate/power to determine the LSP's parameter. But, rather than doing this implicitly by requesting the PCE to determine those parameters (in a PCReq message), it does it explicitly. Delegation does not change the paradigm set by RFC4655 and RFC5440 - but in addition to LSP parameters, it allows the PCE to determine the timing of the LSP setup. If you don't like the term "delegation", please suggest another one. I don't particularly care what we call the mechanism. Thanks, Jan _______________________________________________ Pce mailing list [email protected]<mailto:[email protected]> https://www.ietf.org/mailman/listinfo/pce
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