Intra-Carrier Solutions Enabled by the OIF NNI Erning Ye Nortel Networks

Reference Network Metro E-NNI EMS I-NNI UNI Core Regional Metro

Multiple Control Domains Each domain could be a core, regional, or metro network. The control inside each domain is independent: Different signaling control systems (e.g., proxy) with different protocols (e.g., PNNI, CR-LDP, RSVP, etc.) Different routing control systems (e.g., centralized or distributed) with different protocols (e.g., PNNI, OSPF, IS-IS, etc.) Different protection and restoration mechanisms. Different EMS/NMS Use UNI or NMI to initialize and/or terminate connection services. Different addressing scheme and/or space inside domain. Implementation agreement on E-NNI between domains provides end-to-end services that are transparent to users.

Sub-network Organization and Routing Areas Sub-network E-NNI Sub-network E-NNI Sub-network RA.1 RA.2 RA.top RA.2.2 RA.2.1 RA RA RA.2.2.3

NNI Routing – Requirements Accept ITU-T G.7715 routing requirements, architecture and terminology. Scope of routing area is a consequence of sub- network organization that is described in G.805 at a given layer. Subdivision of the network into routing areas where the areas can contain smaller areas. This creates routing levels. 4 levels of routing hierarchy is required by carriers (OIF NNI requirement). Interoperability between adjacent routing areas is domain-domain routing protocol based on a hierarchical link state protocol.

Sub-network Abstraction and Routing Controller Abstract node Centralized routing control Abstract TE links Distributed routing control Abstract TE links Centralized routing control RA.2.2 RA RA RA RC Abstracted intra-domain link RC

NNI Routing Separation of transport plane and control plane: Separated address space for routing controller and transport nodes Separated topology for routing controller and transport nodes Routing control could be centralized or distributed. Transport sub-network could be abstracted to be one node or several border nodes with abstract intra-domain links. Transport routings main function is to provide path computation to Connection Management (Control plane). In hierarchical routing, the path is computed at certain routing level.

NNI Signaling Domain A Domain B Domain C Client E-NNI UNI SPC Service SC Service Call Segment Network Call Controller Connection Controller UNI Segment Sub-network Segment Sub-network Segment Sub-network Segment UNI Segment NNI Segment NNI Segment

Call/Connection Separation and Call Segments Call model is part of ASON architecture (G.8080), G7713 and OIF NNI. In a multiple control domain environment, the end-to-end call is achieved by concatenating multiple individual UNI, sub- network and NNI call segments. Each call segment could have multiple connections associated with it (e.g., 1+1 path protection, virtual concatenate connections). Network call controllers and connection controllers are defined in G.8080 and used in the NNI signaling specification. NNI call controller is responsible for associating the call segments of NNI and sub-network NNI connection controller is responsible for signaling protocol interoperability

NNI Application – Domain Based Recovery Call/connection separation and call segmentation by ENNI enables domain based protection and restoration ENNI can be used to separate rerouting (recovery) domain. Each rerouting domain contains one or more than one call segment (A rerouting domain may contain other rerouting domains). Each rerouting domain could have its own protection mechanism, e.g., liner protection on ENNI link, APS protection inside one domain, and 1+1 path protection in another domain. The call controller at ingress ENNI performs redial function in the scope of rerouting domain. The failure happens in one domain would not cause connection teardown in other domains.

Recovery Example Client X E-NNI Client X E-NNI