Igor, In such case, would the YANG datastore be updated? I guess not. If not, then the system/controller has to keep this interim state, would it?
Thanks. Young From: Igor Bryskin Sent: Thursday, November 03, 2016 2:34 PM To: Scharf, Michael (Nokia - DE); Leeyoung; Daniele Ceccarelli; CCAMP ([email protected]); [email protected]; TEAS WG ([email protected]); [email protected] Subject: RE: http://tools.ietf.org/html/draft-busibel-teas-yang-path-computation-00 Michael, You are exactly right. The purpose of the "compute-only" TE tunnel is to create/maintain the normal TE tunnel state and (re-)compute TE paths for the TE tunnel connections/LSPs but not signal/provision the LSPs. Igor From: Scharf, Michael (Nokia - DE) [mailto:[email protected]] Sent: Thursday, November 03, 2016 3:17 PM To: Leeyoung; Daniele Ceccarelli; Igor Bryskin; CCAMP ([email protected]<mailto:[email protected]>); [email protected]<mailto:[email protected]>; TEAS WG ([email protected]<mailto:[email protected]>); [email protected]<mailto:[email protected]> Subject: RE: http://tools.ietf.org/html/draft-busibel-teas-yang-path-computation-00 Isn't the intention of defining "compute-only tunnels" to create state in the controller, but not to signal them? If the tunnel should be signaled and resources shall be allocated, why not just configure a vanilla tunnel? Uses cases seem to exist for both variants, and both can be encoded in YANG. Is there anything I miss here? Michael From: Leeyoung [mailto:[email protected]] Sent: Thursday, November 03, 2016 7:49 PM To: Scharf, Michael (Nokia - DE); Daniele Ceccarelli; Igor Bryskin; CCAMP ([email protected]<mailto:[email protected]>); [email protected]<mailto:[email protected]>; TEAS WG ([email protected]<mailto:[email protected]>); [email protected]<mailto:[email protected]> Subject: RE: http://tools.ietf.org/html/draft-busibel-teas-yang-path-computation-00 Hi Michael, I think I am with you on your point. If we use rpc, it is clear. On the other hand, if we were to use "stateful compute-only" it seems that the system/controller has to keep the state of the paths somewhere which is not YANG datastore. My understanding is that YANG datastore is updated only when the path is signaled and resource is allocated. Would this give the system/controller additional burden to keep the "interim" state? Young From: CCAMP [mailto:[email protected]] On Behalf Of Scharf, Michael (Nokia - DE) Sent: Thursday, November 03, 2016 8:58 AM To: Daniele Ceccarelli; Igor Bryskin; CCAMP ([email protected]<mailto:[email protected]>); [email protected]<mailto:[email protected]>; TEAS WG ([email protected]<mailto:[email protected]>); [email protected]<mailto:[email protected]> Subject: Re: [CCAMP] http://tools.ietf.org/html/draft-busibel-teas-yang-path-computation-00 Maybe I miss something, but to me, the domain controller either computes a path stateless, which can be modeled in YANG in an RPC. Or the domain controller computes a path, stores state, and provides access to the result in the YANG datastore. In the latter case, whether resources are allocated, or whether the NEs get actually provisioned, is an orthogonal question. As a side note, I am not sure of I would call a domain controller or an NMS a PCE. Path computation is only a subset of the functions of a domain controller. Michael From: Daniele Ceccarelli [mailto:[email protected]] Sent: Thursday, November 03, 2016 2:49 PM To: Scharf, Michael (Nokia - DE); Igor Bryskin; CCAMP ([email protected]<mailto:[email protected]>); [email protected]<mailto:[email protected]>; TEAS WG ([email protected]<mailto:[email protected]>); [email protected]<mailto:[email protected]> Subject: RE: http://tools.ietf.org/html/draft-busibel-teas-yang-path-computation-00 Can you please explain what the "stateful compute-only" stands for I don't understand what is stateful in a path computation request only. IMHO either I ask the PCE (SDN controller, NMS, whatever) to compute a path and then forget about it or I ask to compute and provision it. I don't understand the value of asking for it and remembering about it. BR Daniele From: Scharf, Michael (Nokia - DE) [mailto:[email protected]] Sent: giovedì 3 novembre 2016 14:45 To: Igor Bryskin <[email protected]<mailto:[email protected]>>; Daniele Ceccarelli <[email protected]<mailto:[email protected]>>; CCAMP ([email protected]<mailto:[email protected]>) <[email protected]<mailto:[email protected]>>; [email protected]<mailto:[email protected]>; TEAS WG ([email protected]<mailto:[email protected]>) <[email protected]<mailto:[email protected]>>; [email protected]<mailto:[email protected]> Subject: RE: http://tools.ietf.org/html/draft-busibel-teas-yang-path-computation-00 We have discussed this before. From an implementer's perspective, the two clean solutions to the problem seem to either stateful "compute-only" tunnels or a stateless RPC. Michael From: mpls [mailto:[email protected]] On Behalf Of Igor Bryskin Sent: Thursday, November 03, 2016 2:34 PM To: Daniele Ceccarelli; CCAMP ([email protected]<mailto:[email protected]>); [email protected]<mailto:[email protected]>; TEAS WG ([email protected]<mailto:[email protected]>); [email protected]<mailto:[email protected]> Subject: [ALU] [mpls]http://tools.ietf.org/html/draft-busibel-teas-yang-path-computation-00 Hi, >From the draft: 6. YANG Model for requesting Path Computation Work on extending the TE Tunnel YANG model to support the need to request path computation has recently started also in the context of the [TE-TUNNEL<https://tools.ietf.org/html/draft-busibel-teas-yang-path-computation-00#ref-TE-TUNNEL>] draft. It is possible to request path computation by configuring a "compute-only" TE tunnel and retrieving the computed path(s) in the LSP(s) Record-Route Object (RRO) list as described in [TE-TUNNEL<https://tools.ietf.org/html/draft-busibel-teas-yang-path-computation-00#ref-TE-TUNNEL>]. This is a stateful solution since the state of each created "compute-only" TE tunnel needs to be maintained and updated, when underlying network conditions change. The need also for a stateless solution, based on an RPC, has been recognized. The YANG model to support stateless RPC is for further study. IB>> Please, note, that in the TE Tunnel model we consider the COMPUTE_AND_FORGET mode. We also consider the concept of path computation action to be defined under the TE tunnel node. All this is to facilitate stateless path computations. Cheers, Igor
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