MEF Protection Work

1. MEF ProtectionWork Pascal Menezes Technical Contributor June 3rd 2003

2. Motivations • Agnostic to any transport and its related protection schemes. • Agnostic to any topology • Does not rely on a certain topology for protection (ex: ring) • Can work with any topology (ring, mesh, mixed, etc) • Degree of protection is dependent on the richness of the redundancy of the topology • Co-exist with any transport protection schemes (ex: SONET, RPR, 802.1d. • Primarily designed for the protection of EVCs. • Based on MPLS based schemes because of the layer 2 service work in IETF for PPVPN (ex: VPLS, VPWS, etc) and PWE3 WGs. This was the scheme chosen because of scalability and inter-MEN connectivity advantages. • It is transparent to IEEE schemes (STP, Link Agg, etc) and it assumes IEEE protection schemes are part of the protection of an Ethernet transport mechanism (ie: it is part of the transport mechanism of the provider). • Subscriber’s protection scheme is transparent (ie: STP, multi-homed) • Extensions to the PRMs for IEEE based technologies • Looking into 802.1ad work and how to extend the framework interworking

3. MEF Protection Work Items • Work done in the MEF Protocol and Transport Group • Protection Requirements Document • Status is Straw Ballot • Protection Framework Document • Status is Straw Ballot • MPLS Protection Implementation Agreement • Status is Straw Ballot

4. MEF Architecture External Reference Model Other UNIs Other Service Networks Subscriber (Internet, PPP, FR, ATM) Service Interworking NNI MEF UNI Metro Ethernet Metro Ethernet Subscriber Network (MEN) Network (MEN) Ethernet Autonomy Y Autonomy X Interworking NNI Network MEF UNI Interworking NNI Subscriber Other Transport Networks Network Interworking NNI MEF UNIs Metro Ethernet Network (MEN) Subscriber Autonomy X

5. MEN Layered Model Ethernet Layer Application Layers MEN Applications (Voice, Video, Data, etc) Application Services Layer (s) IP TCP/UDP Other Protocol Suite(s) MPLS IP PDH Other Ethernet Service Layer Ethernet Services MPLS VC MPLS ATM VC ODUk LOVC ATM VP MPLS OTUk IP other Transport Layer (s) HOVC HOVC HOVC 802.3 PHY OCh 802.3 HOVC PHY STM-N STM-N STM-N OTM-n STM-N Medium (Fiber, Copper, Coax, wireless, etc.) Transport Layers

6. MEF Ethernet Virtual Connection (EVC) Model Ethernet Virtual Connection (EVC) Network Element Metro Ethernet Network Network Element Network Element Customer Network Customer Network Customer Edge (CE) Customer Edge (CE) Network Element User Network Interface (UNI) User Network Interface (UNI) UNI = Service Attributes EVC = Service Attributes

7. MEF Protection Requirements • Protection switching times. • Failure detection requirements • Protection resource allocation requirements • Topology requirements • Failure notification requirements • Restoration and revertiveness requirements • Transparency for end user • Security requirements

8. End to End Protection Service Level Specifications • Connectivity restoration time • Sub 50msec • Sub 200msec • Sub 2 sec • Sub 5 sec • Protection type • 1+1 • 1:1 • 1:n • m:1 • m:n • Revertive or non-revertive mode • Reversion time • Degrade condition threshold (ex: packet loss) • QoS preservation

9. Transport & Protection SLS End-to-End Protection Service Level Specification (SLS) Metro Ethernet Network (MEN) Other Transport (Protection) Other Transport (Protection) CE CE Ethernet (No Protection) Transport Sub-Network Transport Sub-Network Transport Sub-Network

10. Topology & Protection SLS End-to-End Protection Service Level Specification (SLS) NE Backbone Ring Backbone Ring NE NE NE NE Access Mesh NE Access Mesh NE WAN 1 NE NE NE WAN 2 Access Ring Access Ring NE NE NE NE NE NE Metro Ethernet Network (MEN)

11. MEF Protection Reference Model (PRM) Service Level Agreements SLA Ethernet Services Parameters (Protection EVC Service Attributes, Traffic Parameters, etc) Application Protection Constraint Policy APCP End to End Path Protection EEPP Aggregated Line and Node Protection ALNP MEF Protection Mechanism Topology Transport

12. Application Protection Constraint Policy (APCP) Subscriber Service Level Agreement • 99.999 Availability • Packet loss • Delay • Jitter Ethernet Services Parameters Ethernet Service Attributes • EVC Availability • EVC MTTR • etc.. Application Protection Constraint Policy Protection Service Level Specification • ALNP Backup LSPs • 1+1 EEPP Protection Type • 50 Msec Restoration Time • QoS Preserved End-to-End Path Protection (EEPP) Transport Aggregated Line & Node Protection ALNP Topology

13. Backup LSP Primary LSP Backup LSP Aggregated Line and Node Protection (ALNP) NE Ingress NE NE NE Egress NE NE

14. EVC Aggregated Node and Line Protection (ALNP) NE 5 NE 8 NE 2 NE 4 CE A NE 1 NE 7 NE 10 NE 9 NE 3 NE 6 CE Z

15. Backup LSP Primary LSP Backup LSP Secondary LSP End-to-End Path Protection (EEPP) Primary Network NE Ingress NE NE NE Egress NE NE NE NE Redundant Network

16. EVC End-to-End Path Protection (EEPP) NE 5 NE 8 NE 2 NE 4 CE A NE 1 NE 7 NE 10 NE 9 NE 3 NE 6 CE Z

17. Primary LSP Backup LSP Secondary LSP PRM Example NE NE NE Backbone Ring Backbone Ring NE NE Access Mesh NE Access Mesh NE NE NE NE NE WAN 1 NE NE NE NE NE WAN 2 Access Ring Access Ring NE NE NE NE NE NE Metro Ethernet Network (MEN)

18. Protection And ProtectedTransport Sub-Networks

19. PRM and Protected Transport Sub-Networks • Generic approach – PRM interoperability with any kind of transport / topology / protected MPLS-subnetwork / logical-link. • Failures within the protected-transport/subnetwork are provided by itself. • PRM is required for completing the solution in the border between the protected transport/subnetwork and other subnetworks. • Requires indications from the lower layer. • Indications achieved either by the lower-layer or by an OA&M procedure that operates above it. • PRM does not require knowledge of internal structure of the protected subnetwork.

20. PRM and RPR No protection needed NE NE RPR Sub-Network NE NE Protection needed NE NE RPR Sub-Network CE NE CE NE GE Links NE NE NE NE

21. PRM and SONET • Two rings, each protected by technology-specific means, interconnected with point-to-point links. • PRM is required for protecting the P2P links and the border nodes (for example, protection tunnel for node A in blue). A SONET Sub-Network SONET Sub-Network

22. E A C G Protected Transport / Subnetwork F B D H Example Network • A topology containing protected-transport subnetwork as well as unprotected P2P links. Unprotected link

23. E A C G Protected Transport / Subnetwork F B D H Where is PRM Needed? • Failures within the protected subnetwork are protected by its native capabilities. • Failure of border nodes like node A are not protected by the transport/subnetwork.

24. E A C G Protected Transport / Subnetwork F B D H PRM Operation in Protected Transport Sub-Networks • Protection-tunnels are required only for protection of border nodes (unprotected links/nodes). • Failure of a link leading to the border node activates the operation of PRM – switch to the protection tunnel.

25. E A C G Protected Transport / Subnetwork F B D H PRM and Egress Border Failure Case • When the failed node is at the exit of an LSP from the protected subnetwork, the entry node is the one to activate the PRM – switch to the protection tunnel. • This requires receipt of indication about the failure from the protected transport subnetwork or MPLS OAM/Hello.

26. Node Failure Indications in Protected Transport Subnetworks • Some transports have means for indicating about failures and about their type and place. • OAM procedures on LSPs • Heartbeat on links: ex: RSVP Hello Ext.

27. Summary • The PRM scheme is generalized to interoperate with protected-transports / unprotected-transports / protected-subnetworks / logical-links. • PRM does not have knowledge of internal structure of the protected subnetwork. • Protected subnetworks can use any kind of protection mechanism. • Subscribers protection mechanisms are transparent • The PRM is a multi-layers protection model that co-exist together.

28. Thank You