Optical Control Plane, Optical/IP integration Concepts and Issues Greg Bernstein Greg Bernstein

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 Also see: “Control Plane Design for Reliable Optical Networks”, IEEE Communications Magazine, Feb., 2002, by folks at AT&T Labs. Also see

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

6 Standards Bodies and Organizations Charter: Global Telecom Architecture and Standards Membership Fee: minimum $18,900/yr (31,500 Swiss Fr.) No. of Members: 189 Member States Sector Members Member Organizations: Global Service Providers PTTs, ILECs, IXCs Telecom equipment vendors Governments (e.g., US State Department) Charter: Global Telecom Architecture and Standards Membership Fee: minimum $18,900/yr (31,500 Swiss Fr.) No. of Members: 189 Member States 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: 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 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

7 Control Plane Interfaces User Admin Domain User Admin Domain Provider A Admin Domain Provider C Admin Domain UNI E-NNI Provider B Admin Domain firewall L2/L3 Load Balancer Load Balancer firewall L2/L3 Load Balancer Load Balancer Domain A1Domain A2 E-NNI I-NNI Provider A has divided their network into multiple control domains (e.g., vendor, geographic, technology, political, etc.) Provider B’s network is a single control domain 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

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 LTE PTE STELTE PTE STE-STE neighbor discovery 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 Definitions PLR - Physical Layer Regenerator STE - Section Terminating Equipment LTE - Line Terminating Equipment PTE - Path Terminating Equipment STE-LTE neighbor discovery PLR-STE neighbor discovery

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: 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 Traditional IP link state IGPs (OSPF, IS-IS) 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: 4F-BLSR; SRLG: 1, 17 Capacity: 16 STS-1, 4 STS-3, 1 STS-12c Protection: 4F-BLSR; SRLG: 101, 880 Capacity: 16 STS-1, 4 STS-3c, 1 STS-12c Protection: 4F-BLSR; SRLG: 5, 580 Capacity: 28 STS-1, 8 STS-3c, 2 STS-12c Protection: 1:N, N = 3; SRLG: 237 Capacity: 102 STS-1, 30 STS-3c, 4 STS-12c, 1 STS-48c Protection: 1:N, N = 2; SRLG: 138 Capacity: 105 STS-1, 33 STS-3c, 8 STS-12c, 2 STS-48c Protection: 1:N, N = 1; SRLG: 80, 12 Capacity: 97 STS-1, 31 STS-3c, 6 STS-12c, 2 STS-48c NE 1 NE 2 NE 3 NE 4 NE 5

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

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

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 A Control Domain 1 Z Control Domain 3 Control Domain 4 Control Domain 5 Control Domain 2 protocol between domains