Great summary, thanks Ramon. As ever WG contributions are always actively sought, however with H-PCE we would love to hear more operator/provider feedback regarding the applications, procedures and extensions being discussed!
We plan to summarise a number of open H-PCE issues and discuss them during our WG at IETF 82 (Taipei) next month. We will also organise a separate discussion at IETF 82 to give us time to go into more detail for specific areas. Please unicast me if you are interested in participating, and mentioning your H-PCE topic of interest. Br, Dan. -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Ramon Casellas Sent: 14 October 2011 09:13 To: [email protected] Subject: [Pce] ANN: New Version Notification for draft-zhang-pce-hierarchy-extensions-01.txt Dear PCErs, FYI, a new version of draft-zhang-pce-hierarchy-extensions has been uploaded. This document defines PCEP extensions for H-PCE (see below). It is a minor update, and, most importantly, a lot of open issues remain. In this sense, your comments / suggestions are welcome. The current draft already proposes some protocol extensions / encodings to the high-level procedures detailed in the companion framework document. Recent exchanges seem to imply that there is room to revisit requirements and procedures,including * (Parent) TED management: it can be argued that the framework document relies on basic domain connectivity, precluding TE aggregation mechanisms. This seems to be a topic of debate. It has been mentioned in private conversations that it should be a decision of the network operator (based on policies or whatever criterion) to decide the level of information exchange allowed. It clearly seems to depend on the actual scenario (e.g. multi-area WSON vs Inter-AS/carriers) * In any case, decoupling TED management from path computation has been a design criterion within the PCE architecture and this should be applied also to the solutions document. Several mails have hinted the idea of (separate?) approaches to (hierarchical) TED management (cfr. Olivier/Oscar mails) and leaving TED management out of scope (including wrapping TED-related messages out of PCEP / PCNtf). It may be difficult if both functions (path computation and TED management) are slightly coupled (border node identification, endpoint localization and topology aggregation for domain sequence selection, to name a few in which an IGP-based TED may not be sufficient) * Domain representation: the role of domains and domain identifiers is clearly important. We should align with e.g. draft-dhruv on domain sequence, avoid new encodings for domains which could re-use Route sub-objects, etc. * Alternative approaches (Dhruv) suggest to keep the Parent-PCEs topology graph free of BNs (Boundary Nodes) and inter-AS TE link; it being composed only of neighbor domain adjacency. * OF codes: new requirements arise regarding OF codes, including the consideration of actual OF codes (e.g. minimize domain crossing) and policies affecting them (e.g. do not allow domain re-enter). Additionally, there seems to be a need to be able to specify the OF codes to apply at both levels, not only at the parent level but also the child's (i.e. intra-domain level) * Reachability: the current fwk/pcep drafts rely on polling to locate endpoints. This does not preclude some form of caching, but alternative solutions based on notifications/announcements of endpoint (prefixes) have been mentioned. * Exclusions: exclusions need to take into account domains. * Other?... Dan mentioned that discussion and agreement of the above, will help create requirements that will allow us define the Protocol extensions, including PCEP extensions, encoding, error handling and manageability. For this, Dan plans to leave the Framework document open in case new requirements arise. Best regards, Ramon, on behalf of the draft co-authors ------------------------------------------------------------------------- New Version Notification for draft-zhang-pce-hierarchy-extensions-01.txt A new version of I-D, draft-zhang-pce-hierarchy-extensions-01.txt has been successfully submitted by Fatai Zhang and posted to the IETF repository. Filename: draft-zhang-pce-hierarchy-extensions Revision: 01 Title: Extensions to Path Computation Element Communication Protocol (PCEP) for Hierarchical Path Computation Elements (PCE) Creation date: 2011-10-13 WG ID: Individual Submission Number of pages: 19 Abstract: The hierarchical Path Computation Element (PCE) architecture, defined in the companion framework document [I-D.ietf-pce-hierarchy-fwk], allows the selection of an optimum domain sequence and the optimum end-to-end path, to be derived through the use of a hierarchical relationship between domains. This document defines the Path Computation Element Protocol (PCEP) extensions for the purpose of implementing hierarchical PCE procedures which are described the aforementioned document. -- Ramon Casellas, Ph.D. Research Associate - Optical Networking Area -- http://wikiona.cttc.es CTTC - Centre Tecnològic de Telecomunicacions de Catalunya, PMT Ed B4 Av. Carl Friedrich Gauss, 7 - 08860 Castelldefels (Barcelona) - Spain Tel.: +34 93 645 29 00 -- Fax. +34 93 645 29 01 _______________________________________________ Pce mailing list [email protected] https://www.ietf.org/mailman/listinfo/pce _______________________________________________ Pce mailing list [email protected] https://www.ietf.org/mailman/listinfo/pce
