Optical Control Plane, Optical/IP integration Concepts and Issues

1. Optical Control Plane,Optical/IP integration Concepts and Issues Greg Bernstein Gregb@ciena.com

2. Issues and Requirements… • Standards are emerging for control of optical networks… • Primarily aimed at service providers and carriers • Some of these efforts were started under vastly different circumstances than the optical networking industry now faces • Some of these control standards were ahead of any interoperability standards at the optical layer • Good IP/Optical integration would require at least: • Information about the optical network topology/resources • Timely IP level traffic statistics

3. Also see: “Control Plane Design for Reliable Optical Networks”, IEEE Communications Magazine, Feb., 2002, by folks at AT&T Labs. Also see http://www.networkwatch.rhk.com/ShowAnalysis.asp?analysisId=106

4. Goals: Automation of Optical Control Functions • Automatic Neighbor Discovery • Allows a node to determine the identity of each neighboring node and the set of links that connect them • Topology and Resource Status Dissemination • Allows every node to automatically discover the complete network topology and resources • Signaling for Connection Provisioning • Allows the establishment and restoration of a path from one end of the connection

5. 2. Global Topology Dissemination 1. Neighbor Discovery OUNI 3. Connection Request 4. Path Calculation (NE-based or EMS-based) 5. Establish Connection Optical Control Plane Functions Inventory & Resource Management NETWORK MGMT PLANE User User CONTROL PLANE DATA PLANE Dynamic Provisioning

6. Charter: Global Telecom Architecture and • Standards • Membership Fee: minimum $18,900/yr (31,500 Swiss Fr.) • No. of Members: 189 Member States + 434 Sector Members • Member Organizations: • Global Service Providers • PTTs, ILECs, IXCs • Telecom equipment vendors • Governments (e.g., US State Department) • Charter: Evolution of the • Internet (IP) Architecture • Membership Fee: None • Membership: Individuals – community model • Active Participants: • ISPs • Service Provider IP Divisions • IP/Ethernet Vendors • Charter: Development of Optical • Networking Products and Services • Membership Fee: $8000/yr • No. of Members: 312 Principal Members • Member Organizations: • PTTs, ISPs, ILECs, IXCs • Optical Networking Vendors Standards Bodies and Organizations

7. Load Load Balancer Balancer L2/L3 L2/L3 firewall firewall L2/L3 L2/L3 firewall firewall Load Load Balancer Balancer Control Plane Interfaces User Admin Domain User Admin Domain Provider C Admin Domain UNI UNI Provider A Admin Domain Provider B Admin Domain E-NNI E-NNI I-NNI Provider B’s network is a single control domain Provider A has divided their network into multiple control domains (e.g., vendor, geographic, technology, political, etc.) E-NNI UNI: operations between end-user and service provider admin domains E-NNI: multi-control domain operation for a single service provider; multi-control domain operation among different service providers I-NNI: intra-control domain operation Domain A1 Domain A2 I-NNI I-NNI

8. Why do Neighbor Discovery? • Allows automatic inventorying of physical links between nodes • Can determine inconsistent physical wiring • Allows automatic identification of node-pair neighbors • Useful for path computation and signaling

9. Neighbor Discovery at which layer? Between which layer? PLR-STE neighbor discovery STE-LTE neighbor discovery STE-STE neighbor discovery PLR PLR STE PTE PTE LTE LTE STE LTE-LTE neighbor discovery PLR-PLR neighbor discovery Definitions PLR - Physical Layer Regenerator STE - Section Terminating Equipment LTE - Line Terminating Equipment PTE - Path Terminating Equipment

10. Optical Link State Routing • A way to discover and disseminate topology and resource information independent of the EMS • Offloads the EMS from performing this task • Makes this information available at every node  enhanced robustness in the event of major network problems • Timely updates of changes to all nodes

11. Routing Roles: Traditional IP link state IGPs (OSPF, IS-IS) • Discovery portion • Hello protocol (assumes data and control planes are the same) • Not applicable, in general, to optical networks • Topology Dissemination • Information concerning nodes (including reachability) and links in the network • Want and need more information for optical networks • Route Computation • To give IP forwarding table (heavily constrained due to hop-by-hop forwarding paradigm) • Overly simplistic for optical networks Acronyms: IP (Internet Protocol), IGPs (Internal Gateway Protocols), OSPF (Open Shortest Path First), IS-IS (Intermediate System to Intermediate System)

12. Example Network View Protection: 1:N, N = 3; SRLG: 237 Capacity: 102 STS-1, 30 STS-3c, 4 STS-12c, 1 STS-48c Protection: 4F-BLSR; SRLG: 1, 17 Capacity: 16 STS-1, 4 STS-3, 1 STS-12c NE 3 NE 1 NE 4 Protection: 4F-BLSR; SRLG: 5, 580 Capacity: 28 STS-1, 8 STS-3c, 2 STS-12c Protection: 1:N, N = 2; SRLG: 138 Capacity: 105 STS-1, 33 STS-3c, 8 STS-12c, 2 STS-48c Protection: 4F-BLSR; SRLG: 101, 880 Capacity: 16 STS-1, 4 STS-3c, 1 STS-12c NE 2 NE 5 Protection: 1:N, N = 1; SRLG: 80, 12 Capacity: 97 STS-1, 31 STS-3c, 6 STS-12c, 2 STS-48c

13. Connection Provisioning • Goals • Offload the EMS by distributing control • Also adds scalability, survivability and potential for more services • Interoperability • General Solution: Use a signaling protocol! • Signaling has been used in the telephone network for 60 years or more (signaling is rather new in data networks though…) • Need to be careful with “behavioral” aspects… • e.g., call clearing is not an acceptable default behavior in the transport domain! • Other benefit: a robust, bandwidth efficient restoration mechanism… • There are a number of different signaling protocols being extended

14. Inter-Domain Networking (NNI) The “Inter-domain” model is an inherent part of the current ITU-T standards for the control of optical networks

15. Domain Model • Networks are organized as multiple domains: • Administrative purposes • Scaling purposes • Security and Isolation • Technology / Vendor differences… • Examples • Internet Autonomous Systems (AS) • ITU-T G.805/ASON Domain Model

16. Deployment Issues • Within Domain: homogeneous systems and protocols • Different Domains: heterogeneous systems and protocols Carrier A Domain Y Domain X UNI UNI Carrier B Feature-Rich Intra-domain Protocol Domain Z Generic Inter-domain Protocol Generic Interdomain Protocol UNI  Domain Model

17. Control Domain Concepts • Separation of Control Mechanisms • Protocols used between domains independent of what protocols used within domain • Internal operation of domain “invisible” outside the domain • Independence of internal protection or restoration mechanisms • Carrier Uses for Domains • Inter-vendor interoperability • Gatekeeper mechanism for suppressing signaling or routing storms between domains • Technology differences (all-optical, SDH,…) • Service differences (restoration, etc…)

18. OIF / ITU-T NNI between Control Domains • Goals • Enable interoperability by utilizing discovery, signaling and routing protocols between control domains protocol between domains A Control Domain 2 Control Domain 1 protocol between domains protocol between domains Control Domain 4 Z Control Domain 3 Control Domain 5