Hi Mustapha, Jon said this in his earlier mail -
> Although I'm not convinced it would be a good idea operationally, > I don't think there's any need to prevent the path type changing > on the PCUpd, if an explicit PATH-SETUP-TYPE is given. That is, > draft-ietf-pce-lsp-setup-type, as a base draft, should allow that > flexibility. A given device may choose not to allow that, of course. And I agree with that. In case of message which is in a "response" such as PCRep, PCRpt it MUST have the same PST. But PCUpd and PCInitiate are different and keeping a door open for allowing the change of PST could allow better migration from RSVP-TE to SR for existing tunnels. How about we update the text in the draft to explicitly say that this is about PCC's local policy and PCC MAY send an error in case the local policy doesn't allow changing of PST? Thanks! Dhruv PS. And for what's it's worth, I agree with leaving the selection of PST for a future extension. > -----Original Message----- > From: Pce [mailto:pce-boun...@ietf.org] On Behalf Of Aissaoui, Mustapha > (Nokia - CA/Ottawa) > Sent: 17 November 2017 05:18 > To: Jonathan Hardwick <jonathan.hardw...@metaswitch.com>; Julien Meuric > <julien.meu...@orange.com>; stephane.litkow...@orange.com > Cc: pce@ietf.org > Subject: Re: [Pce] Clarifications on PST handling in draft-ietf-pce-lsp- > setup-type & draft-ietf-pce-segment-routing > > Jon, > While I do not have an issue with enforcing the PST TLV be included in the > below message types, we still need to answer Stephane's last question in > his original email. That is whether the PST is allowed to change during > the lifetime of the LSP. I am hoping the answer is no meaning that once a > LSP with a PLSP-ID is established, a subsequent PCUpd message with a PST > type that does not match the type in the original message which created > that PLSP-ID (PCReq or PCInitiate) should result in the PCC returning a > PCErr message with Error-Type = 21 (Traffic engineering path setup error) > and Error-Value = 2 (Mismatched path setup type). > > If that is the understanding of this group, we should explicitly document > it in draft-ietf-pce-lsp-setup-type. > > Mustapha. > > > -----Original Message----- > > From: Pce [mailto:pce-boun...@ietf.org] On Behalf Of Jonathan Hardwick > > Sent: Thursday, November 16, 2017 6:19 AM > > To: Julien Meuric <julien.meu...@orange.com>; > > stephane.litkow...@orange.com > > Cc: pce@ietf.org > > Subject: Re: [Pce] Clarifications on PST handling in > > draft-ietf-pce-lsp-setup-type & draft-ietf-pce-segment-routing > > > > Hi Julien, see [Jon]s below... > > > > -----Original Message----- > > From: Julien Meuric [mailto:julien.meu...@orange.com] > > Sent: 16 November 2017 17:28 > > To: Jonathan Hardwick <jonathan.hardw...@metaswitch.com>; > > stephane.litkow...@orange.com > > Cc: pce@ietf.org > > Subject: Re: [Pce] Clarifications on PST handling in > > draft-ietf-pce-lsp-setup-type & draft-ietf-pce-segment-routing > > > > Hi, > > > > Glad to see we are converging. To make sure we are on the same page > > (solution > > (2) referring to a shortcut), the conclusion is that, as soon as PST is > not 0 (i.e. > > RSVP-TE), we always include the PST TLV in PCReq, PCRep, PCUpd, PCRpt > > and > > PCInitiate: is that right? > > > > [Jon] Yes. > > > > This leads me to another question. Over a PCEP session supporting > > multiple types, we do not have a mean to send a PCReq leaving the type > > selection to the PCE (no TLV implying type 0). Do we consider a mean > > to support that? (Could be 0xFF or a flag from the "Reserved" field.) > > > > [Jon] It could be done, but do we need it? This could be added later > > without penalty. > > > > Thanks, > > > > Julien > > > > > > Nov. 16, 2017 - jonathan.hardw...@metaswitch.com: > > > > > > Hi Stephane > > > > > > > > > > > > OK, let's go with solution (2). That is, if the PATH-SETUP-TYPE is > > > not present in a message, then it unambiguously means that the path > > > setup type is RSVP-TE. Then implementations don't have to try to > > > infer the path setup type from other objects or previous messages. > > > > > > > > > > > > I am revising draft-ietf-pce-lsp-setup-type at the moment to address > > > an earlier comment from Julien, so I will include this clarification > > > in the next revision. > > > > > > > > > > > > Thanks for the input! > > > > > > Cheers > > > > > > Jon > > > > > > > > > > > > > > > > > > *From:*stephane.litkow...@orange.com > > > [mailto:stephane.litkow...@orange.com] > > > *Sent:* 15 November 2017 13:52 > > > > > > > > > > > > Hi Jon, > > > > > > > > > > > > Thanks for your feedback. > > > > > > I see two possibilities here. > > > > > > 1. When the PATH-SETUP-TYPE is not present in a PCUpd, it should be > > > inferred from the latest one received (in a PCInitiate or in a > > > PCUpd). When initiating an LSP, the PCInitiate contains the PST to > > > let the PCC know about the path type. Then, it can be omitted in > > > further PCUpd except when the PCE wants to change the path type. > > > At that time, it sends a PCUpd with a new PATH-SETUP-TYPE value > > > and then it does not need to include it in further updates until > > > the PCE needs to change it again. > > > 2. We mandate the PCE to put the PATH-SETUP-TYPE in all PCUpd. > > > > > > > > > > > > IMO, solution 2) is easier for implementations and operation. > > > > > > > > > > > > Brgd, > > > > > > > > > > > > Stephane > > > > > > > > > > > > > > > > > > *From:*Jonathan Hardwick [mailto:jonathan.hardw...@metaswitch.com] > > > *Sent:* Wednesday, November 15, 2017 09:28 > > > *To:* LITKOWSKI Stephane OBS/OINIS; pce@ietf.org > > > <mailto:pce@ietf.org> > > > *Subject:* RE: Clarifications on PST handling in > > > draft-ietf-pce-lsp-setup-type & draft-ietf-pce-segment-routing > > > > > > > > > > > > I think it should be acceptable for the PCUpd not to include the > > > PATH-SETUP-TYPE, with the implication that there is no change to the > > > path type. > > > > > > > > > > > > Although I'm not convinced it would be a good idea operationally, I > > > don't think there's any need to prevent the path type changing on > > > the PCUpd, if an explicit PATH-SETUP-TYPE is given. That is, > > > draft-ietf-pce-lsp-setup-type, as a base draft, should allow that > > > flexibility. A given device may choose not to allow that, of course. > > > > > > > > > > > > Does that sound reasonable? > > > > > > Cheers > > > > > > Jon > > > > > > > > > > > > > > > > > > *From:*Pce [mailto:pce-boun...@ietf.org] *On Behalf Of > > > *stephane.litkow...@orange.com > > > <mailto:stephane.litkow...@orange.com> > > > *Sent:* 14 November 2017 00:38 > > > *To:* pce@ietf.org <mailto:pce@ietf.org> > > > *Subject:* [Pce] Clarifications on PST handling in > > > draft-ietf-pce-lsp-setup-type & draft-ietf-pce-segment-routing > > > > > > > > > > > > Hi WG, > > > > > > > > > > > > I'm facing an interop issue between two PCEP implementations. > > > > > > PCE from vendor1 sends the PCInitiate for an SRTE LSP using the > > > PST=1 in the SRP Object. > > > > > > PCC from vendor2 handles it correctly and delegates the LSP to the > > > PCE using PST=1. > > > > > > When the PCE sends a PCUpdate message, it does not set the PST TLV > > > in the SRP Object. > > > > > > The PCC rejects the PCUpdate because of a bad ERO subobject type. It > > > reads the PCUpdate as having PST type=0. > > > > > > > > > > > > Based on my reading of draft-ietf-pce-lsp-setup-type & > > > draft-ietf-pce-segment-routing. > > > > > > PST draft tells that for the PCE Initiation case, the PCE MAY > > > include the PST if the message does not ave any other means of > > > indicating the path setup type. SR draft tells "In order to setup an > > > SR-TE LSP using SR, RP or SRP object MUST include PATH-SETUP-TYPE > > > TLV". Unfortunately it does not specify explicitly in which message. > > > From a reading perspective, we can understand from "In order to > > > setup" that it applies to the PCInitiate message. But nothing tells > > > about the PCUpdate message. > > > > > > However draft-ietf-pce-lsp-setup-type tells for the stateful PCE > > > case > > > that: "if the path setup type cannot be unambiguously inferred from > > > ERO or any other object or TLV, PATH-SETUP-TYPE TLV MAY be used in > > > PCRpt and PCUpd messages." > > > > > > In our case (PCE initiated) as the LSP has initially been setup > > > through a PCInitiate message having the PST TLV, the PCC can infer > > > that futher updates will use EROs associated with the same PST. > > > > > > > > > > > > Or do we allow to change the PST through PCUpdate messages which may > > > require to always set the PST ? (moving from RSVP-TE to SR or the > > > other way for a particular LSP) > > > > > > > > > > > > I would like to hear opinions of the WG on that problem ? > > > > > > > > > > > > Thanks, > > > > > > > > > > > > Brgds, > > > > > > > > > > > > > > > > > > Orange logo <http://www.orange.com/> > > > > > > > > > > > > *Stephane Litkowski * > > > Network Architect > > > Orange/SCE/EQUANT/OINIS/NET > > > > > > Orange Expert Future Networks > > > > > > phone: +33 2 23 *06* 49 83 > > > > > <https://monsi.sso.francetelecom.fr/index.asp?target=http%3A%2F%2Fclic > > voice.s > > so.francetelecom.fr%2FClicvoiceV2%2FToolBar.do%3Faction%3Ddefault%26ro > > ot service%3DSIGNATURE%26to%3D+33%202%2023%2028%2049%2083%20> NE W ! > > > mobile: +33 6 71 63 27 50 > > > > > <https://monsi.sso.francetelecom.fr/index.asp?target=http%3A%2F%2Fclic > > voice.s > > so.francetelecom.fr%2FClicvoiceV2%2FToolBar.do%3Faction%3Ddefault%26ro > > ot service%3DSIGNATURE%26to%3D+33%206%2037%2086%2097%2052%20> NE W ! > > > stephane.litkow...@orange.com <mailto:stephane.litkow...@orange.com> > > > > > > > > > > > > > > ______________________________________________________________________ > > > ___________________________________________________ > > > > > > Ce message et ses pieces jointes peuvent contenir des informations > > > confidentielles ou privilegiees et ne doivent donc pas etre > > > diffuses, exploites ou copies sans autorisation. Si vous avez recu > > > ce message par erreur, veuillez le signaler a l'expediteur et le > > > detruire ainsi que les pieces jointes. Les messages electroniques > > > etant susceptibles d'alteration, Orange decline toute responsabilite > > > si ce message a ete altere, deforme ou falsifie. Merci. > > > > > > This message and its attachments may contain confidential or > > > privileged information that may be protected by law; they should not > > > be distributed, used or copied without authorisation. > > > If you have received this email in error, please notify the sender > > > and delete this message and its attachments. > > > As emails may be altered, Orange is not liable for messages that > > > have been modified, changed or falsified. > > > Thank you. > > > > > ______________________________________________________________________ > > > ___________________________________________________ > > > > > > Ce message et ses pieces jointes peuvent contenir des informations > > > confidentielles ou privilegiees et ne doivent donc pas etre > > > diffuses, exploites ou copies sans autorisation. Si vous avez recu > > > ce message par erreur, veuillez le signaler a l'expediteur et le > > > detruire ainsi que les pieces jointes. Les messages electroniques > > > etant susceptibles d'alteration, Orange decline toute responsabilite > > > si ce message a ete altere, deforme ou falsifie. 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