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This draft discusses the testing experience and extensions for ASON routing, specifically the OIF bandwidth advertisement and ISCD extensions.
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ASON routing implementation and testing ASON routing extensions IETF 76 – Hiroshima – Nov‘09 L. Ong (Ciena) lyong@ciena.com
Draft on ASON Routing Testing Experience • CCAMP work on ASON Routing is Experimental • No standard codepoints have been allocated • OIF has experimented with similar extensions • Transport-only instance of OSPF (no IP routing) • Advertising reachable local address prefixes • Advertising local/remote TE router IDs for scoping of routing information (Li/Pi mapping) • Details in draft-ong-gmpls-ason-routing-exper-00.txt • OIF would like to see this work on Standards Track • Contribution provides input on testing of similar extensions • Tested at interops since 2003, most recently 2007 & 2009 • At least 7 independent implementations each time • OIF extensions are offered for CCAMP use • Can these extensions be adopted directly? “Running code” • Will experience help to move work to Standards Track?
OIF Bandwidth advertisement extension • OIF ISCD extension: • Combines advertisement of bandwidth for multiple signal types in one ISCD • Advertises separate availability per signal type • Why • Standard signal types are placed along specific boundaries • Availability for new connections at STS-3c/VC-4 or STS-12c/VC-4-4 depends on position of occupied timeslots • Cannot be determined from total unreserved bytes per second • Combination is more efficient than separate ISCD or LSA per signal type • Most link attributes are common across signal types, combining reduces duplication • Although these are “layers” in ITU-T sense, they share the same switching matrix STS-12c STS-3c STS-1
Draft on Extended Routing Functions • Follow up on previous liaison providing requested detail: • Layer-scoped Link Attributes • Layer = VC-3, VC-4 • Connections available at a particular layer • Attributes (e.g., metric) that differ for a layer • Local Connection Type • CP or TCP (switch or terminate) • Within layer, not multilayer/adaptation-related • Looking for better solution than ISCD/IACD • NSAP format Local Node Prefix • In addition to IPv4 and IPv6 formats • New draft submitted with more detail • draft-theillaud-gmpls-ason-routing-add-fcts-01.txt
Layer-scoped link attributes • G.7715.1 specifies a set of link characteristics specific to a particular layer network • Most of these attributes would be common across layer networks supported by a particular link • However, OIF members believe that some attributes may take different values for different TDM layers, esp: • Link available bandwidth • TE metric • Possibly others such as administrative group • Therefore, the ability to support advertisement of common attributes on a per link basis but also to allow some attributes to be scoped to a layer would be highly useful
Layer-scoped link attributes potential solutions • Advertising multiple TE LSAs for a given link, the LSA itself scoping the attributes • Is this allowed by GMPLS protocol? • Is this an efficient mechanism? • New sub-TLV allowing to scope some attributes to a specific layer • Proposed in the draft, see draft for details
Link associated local connection type • Section 4.1 in draft-ietf-ccamp-gmpls-ason-routing-ospf-09.txt proposes to rely on the ISCD(s) advertised by each link endpoints, to infer the link local connection type • Inferring the local connection type from ISCDs is not sufficient • See example • An explicit local connection type parameter is desirable • detailed proposed extension contained in the draft
Link associated local connection type • For this link, both nodes would advertise the same ISCD for the VC-3 layer. Node 1 would in addition advertise an ICSD for the VC-4 layer. • A path computation entity would believe that a HO VC-3 connection can be set up across this link, while it cannot • Node2 “terminates” both HO VC-4 and HO VC-3 layers • Node2 can switch a LO VC-3 layer (from a terminated HO VC-4 signal) Node1 Node2 • Switching functions • LO VC-3 • Switching functions • HO VC-4 • HO VC-3
Thanks to contributors • Richard Graveman (Department of Defense) • Hans-Martin Foisel (Deutsche Telekom) • Thierry Marcot (France Telecom) • Evelyne Roch (Nortel Networks) • Jonathan Sadler (Tellabs) • Yoshiaki Sone (NTT Corporation) • Takehiro Tsuritani (KDDI R&D Laboratories) • Xihua Fu (ZTE)