Thanks Qin, See also my answer to Dhruv since that modifies some of the text you are asking about.
> 1. Section 19, second paragraph says: > " > There is a subtle distinction between an NMS and an Active PCE with > LSP delegation. An NMS is in control of the LSPs in the network and > can request that they are set up, modified, or torn down. An Active > PCE can only make suggestions about LSPs that have been delegated to > the PCE by a PCC . > " > Is PCC NMS or LSR headend? If PCC is NMS, it is a little bit confusing to compare > Active PCE with LSP delegation with NMS? I thought about this a bit and decided that the text is right as it stands. The possibilities are: - An NMS uses a passive PCE to compute paths and then instructs the network. - An NMS uses an active PCE to recommend *to*it* the changes to delegated LSPs and to recommend *to*it* new LSPs to be instantiated, then the NMS instructs the network. - An NMS instructs an LSR to set up an LSP and the LSR consults a passive PCE to determine a path. - An NMS instructs an LSR to set up an LSP and the LSR delegates the LSP to an active PCE. - An LSR determines to set up an LSP and the LSR consults a passive PCE to determine a path. - An LSR uses an active PCE to recommend to it the changes to delegated LSPs and to recommend *to*it* new LSPs to be instantiated, The distinction in all these cases is that the active PCE makes recommendations to the PCC, but the NMS issues instructions to the network. I think that one word of clarification comes out of this. In the text you quote I will s/request/command/ > 2. Section 20 says: > " > | Stateless | Stateful | > ------------------------+-----------+-----------+ > Passive | 1 | 2 | > Active delegated LSPs | 3 | 4 | > Active suggest new LSPs | 5 | 6 | > Active instantiate LSPs | 7 | 7 | > " > What’s the difference between delegated LSP and suggested new LSP? What’s > the difference between suggest new LSP and Instantiate LSPs? Is Active > Instantiate LSPs related to PCE initiated LSP? Well, this is not only the subject of the previous sections, but also has been the focus of a bit of debate on the list. > What’s the difference between delegated LSP and suggested new LSP? The former is an LSP that has been set up and is then passed (delegated) to the active PCE for it to recommend changes. The latter does not exist as an LSP until the active PCE recommends its instantiation. > What’s the difference between suggest new LSP and Instantiate LSPs? "Suggestion" is recommending instantiation. But just because something is recommended, doesn't mean you do it! (Except in some cultures: I had an interesting discussion with a TSA officer about this once ;-) On the other hand, "instantiate LSP" implies absolute control. > Is Active Instantiate LSPs related to PCE initiated LSP This is the point Dhruv and I are trying to dance around. The topic only applies to active PCEs, so we need only compare "instantiate" with "initiate". The WG draft on LSP initiation does not (IMHO) have an active PCE issuing commands that the PCC must obey. I think it has a PCE that "recommends the instantiation of LSPs" and the PCC can determine according to policy and weather conditions if it wishes to follow the recommendation. Thus, the WG draft on LSP initiation does not talk about what I call "LSP instantiation" because it does not compel the PCC to set up the LSP. This is consistent with my view that a PCE cannot instantiate an LSP, it can only recommend instantiation. > 3. Section 22, last bullet says: > " > The VNTM will need to issue provisioning requests/commands to the > lower layer networks to cause LSPs to be set up to act as TE links > in the higher layer network. A number of potential protocols exist > for this function as described in [I-D.farrkingel-pce-abno- > architecture], but it should be noted that it makes a lot of sense > for this interface to be the same as that used by an Active PCE > when providing paths to the network. > " > Why VNTM should issue provision request? Isn’t it the job of Provision manager? > Or VNTM ask Provision manager to issue provision request? Good catch. Everything should go via Provisioning Manager. This text was written before Provisioning manager added to ABNO. I'll update. > 4. Section 23, 2nd paragraph > s/network note/network node ack > 5. Section 23, 3rd paragraph says: > " > Conversely, a centralized database of resources and LSPs such as > maintained by a Stateful PCE can be enhanced with a time-based > booking system. If the PCE is also Active, then when the time comes > for the LSP to be set up (or later, when it is to be torn down) the > PCE can control the network. > " > It looks this sentence breaks and can not be parsed from “and LSP such as > maintained by a stateful PCE” > It looks “such as” needs to be removed or > s/ and LSPs such as maintained by/such as LSP maintained by The "such as" applies to the DB. I'll reword. > 6. Section 23, last paragraph, says: > " > It may also be necessary > to reposition existing or planned LSPs as new bookings arrive. > Furthermore, the booking database that contains both the scheduled > LSPs and their impact on the network resources can become quite > large. > " > Is planned LSP scheduled LSP? If not, tell difference, if yes, make consistent. The term "scheduled LSP" is not used, so nothing to make consistent with, I think. The section begins... LSP scheduling or calendaring is a process where LSPs are planned ahead of time, and only set up when needed. ...so to me it is clear what a planned LSP is. If you have a specific suggestion, then I'd be happy to hear it. Many thanks, Adrian _______________________________________________ Pce mailing list [email protected] https://www.ietf.org/mailman/listinfo/pce
