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Inter-carrier NNI (mainly about routing)

Inter-carrier NNI (mainly about routing). Olle Pers, TeliaSonera, Sweden NOBEL WP4, Munich, June 2005. A carrier's perspective. We know and control our own network, but we don't know the other networks and we don't trust them we need well defined control interfaces

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Inter-carrier NNI (mainly about routing)

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  1. Inter-carrier NNI(mainly about routing) Olle Pers, TeliaSonera, Sweden NOBEL WP4, Munich, June 2005

  2. A carrier's perspective • We know and control our own network, but • we don't know the other networks • and we don't trust them • we need well defined control interfaces • addressing, routing, signalling

  3. The draft text • A first version is on the server - currently a rather stand-alone document. • There are missing aspects and open questions ! • Which parts should go into D25? And how do they fit in there? • Please comment on the existing text !

  4. What's missing? The current text focuses on interconnection of networks that provide switched L1 connections. For NOBEL, this should be extended with discussion on: • multiple transport layers • call signalling • VPNs (?) • (service plane?)

  5. Which services? The basic purpose is to support client services end-to-end across multiple carrier domains. • all the network services identified by NOBEL ? • L1 VPN, L2 VPN, L3 VPN, Business IP, Public IP • all services that the client can request at UNI ? • the NOBEL UNI (as discussed in D18) is not very clear on services and functions.

  6. Control Plane Requirements For Network A to reach destination D - what's needed? • A globally valid reference for D. (addressing) • Basic message from A to B: "Connect me to D" (signalling) • Minimum info from B to A: "You can reach D via me" (routing) Network A Network B Network C 1 3 5 D 6 4 2

  7. Routing information What more should be advertised from B to A? • service types (l, VC-4, Eth-VPN, Public IP...) • capabilities (QoS, recovery, diversity, ...) ? • "map of networks" or "path to destination" ? • networks (B, C)? interfaces (3,4,5,6) ? • path metrics (capacity, latency, price, ...) ? • The more information per destination, the harder to aggregate based on prefix...

  8. Multi-layer: addressing Approach 1: A network element or interface has one single address, to be used for both L1 and L2 connections, and IP packets. Approach 2: The network uses different addresses for different layers and services. There may be pros and cons with both options. For the inter-carrier NNI - we can not assume that all the neighbor networks have made the same choice. How should endpoint reachability be advertised then?

  9. Multi-layer: routing Inside a carrier domain, we can have • a different routing instance for each switching layer, or • a single routing process for all layers. [unified GMPLS control, the long term scenario of NOBEL D11] For the inter-carrier NNI: • BGP is the standard - but only for connectionless IP • How to carry information about other layers - should we use separate protocols, or make extensions to BGP, or... ? • are there any other protocols available ?

  10. Using the "internal E-NNI" ? The "intra-carrier E-NNI" is not yet specified in detail... • separation of control and transport plane, • choice of routing protocol, • subdivision into areas, addressing, • multilayer path computation, • call signalling, VPN handling... However, inter-carrier has other goals: • Information is summarized at domain boundaries • only for scalability (intra) - mainly for confidentiality (inter) . • Path is computed to optimize resources • in all domains together (intra) - in each domain separately (inter).

  11. Other issues... Path computation involving multiple layers • very interesting topic, but only for intra-carrier Path computation over multiple carrier domains • "full AS path" or "next hop" ? • how to avoid loops ? • what the other networks allow Call-connection separation • signalling to be analyzed when described for the UNI and/or internal NNI. • no impact foreseen on routing or addressing

  12. VPN support • Which VPN actions should be signalled? • create new VPN? • add client to existing VPN? • new connection within existing VPN? • Should existing VPNs be advertised? • Should the E-NNI handle any VPN-specific addressing? • ...wait until we define how to handle VPNs in a single domain.

  13. (service plane ?) • E-NNI is about networks and network services. • "Inter-carrier" assumes there is no umbrella NMS. • The "service plane" is not there yet... wait and see

  14. Summary • This was not the answers - but some questions and open issues. • Discussion is welcome - continue on the mailing list... ....just one more slide... on routing in general...

  15. Routing is about... • Information content • which information is handled and stored in the "database" ? • Distribution mechanism • The OSPF way: same info to all neighbors, periodic flooding, no acks, information timeout, • The BGP way: specific info per peer, incremental updates, acks, explicit withdraw, • Path/Route Selection • can be standardised and integrated in the routing process (BE) • or an independent function, working on the routing info... (TE)

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