Requirements for MEF E-Tree Support in VPLS draft-key-l2vpn-vpls-etree-reqt-00

1. Requirements for MEF E-Tree Support in VPLSdraft-key-l2vpn-vpls-etree-reqt-00 Presenter: Frederic Jounay IETF78, July 2010 Authors: Raymond Key Simon Delord Frederic Jounay

2. Introduction This Internet draft provides functional requirements for MEF E-Tree support in VPLS. Considerable number of service providers have adopted VPLS to provide MEF E-LAN services to customers. Service Providers now need a simple and effective solution to emulate E-Tree services in addition to E-LAN services on their MPLS networks. VPLS is IETF standard, refer to RFC4761 and RFC4762. 2

3. MEF Multipoint Services Within the context of a MEF multipoint service Each endpoint is designated as either Root or Leaf Root can communicate with all other endpoints Leaf can only communicate with Roots but not Leafs Two multipoint service types are defined in MEF6.1 E-LAN (Multipoint-to-Multipoint) E-Tree (Rooted-Multipoint) The only difference between E-LAN and E-Tree E-LAN has Roots only, any-to-any connectivity E-Tree has both Roots and Leafs, need to enforce communication restriction between Leafs 3

4. E-Tree Use Cases E-Tree has a variety of use cases Broadcast Video Broadcast/Multicast Video plus Control Channel IEEE 1588 PTPv2 Clock Synchronisation Mobile Backhaul Internet Access Hub & Spoke VPN Wholesale Access Device Management 4

5. Generic E-Tree Service A generic E-Tree service supports multiple Root endpoints. Whether a particular service needs to support single or multiple Roots depends on the target application. A generic E-Tree service supports all the following traffic flows: Ethernet Unicast between Roots Ethernet Unicast between Root and Leaf Ethernet Broadcast/Multicast from Root to Roots & Leafs Ethernet Broadcast/Multicast from Leaf to Roots Whether a particular service needs to support all the above or only a subset depends on the target application. 5

6. Problem Statement Considerable number of service providers have adopted VPLS to provide MEF E-LAN services to customers. Service Providers now need a simple and effective solution to emulate E-Tree services in addition to E-LAN services on their MPLS networks. The current standard VPLS provides any-to-any connectivity for all ACs, does not classify AC into Root or Leaf, does not include any mechanism of communication restriction between specific ACs, therefore is insufficient for emulating generic E-Tree service over MPLS network. 6

7. Two PE with Root & Leaf <------------E-Tree------------> +---------+ +---------+ | PE1 | | PE2 | +----+ | +---+ | | +---+ | +----+ |CE01+----AC1----+--+ | | | | +--+----AC5----+CE05| +----+ (Root AC) | | V | | | | V | | (Root AC) +----+ +----+ | | | | | | | | +----+ |CE02+----AC2----+--+ | | Ethernet | | +--+----AC6----+CE06| +----+ (Root AC) | | S +--+-----PW-----+--+ S | | (Root AC) +----+ +----+ | | | | | | | | +----+ |CE03+----AC3----+--+ | | | | +--+----AC7----+CE07| +----+ (Leaf AC) | | I | | | | I | | (Leaf AC) +----+ +----+ | | | | | | | | +----+ |CE04+----AC4----+--+ | | | | +--+----AC8----+CE08| +----+ (Leaf AC) | +---+ | | +---+ | (Leaf AC) +----+ | | | | +---------+ +---------+ When PE2 receives a frame from PE1 via the PW, PE2 does not know whether the ingress AC is a Leaf AC or not, therefore does not have sufficient information to enforce the Leaf-to-Leaf communication restriction. (Example: CE04 sends a broadcast frame to PE1 via AC4.) 7

8. Functional Requirements A solution MUST prohibit communication between any two Leaf ACs in a VPLS instance. A solution MUST allow multiple Root ACs in a VPLS instance. A solution MUST allow Root AC and Leaf AC of a VPLS instance co-exist on any PE. 8

9. Applicability A solution MUST identify which VPLS standards the solution is applicable to, RFC4761 or RFC4762 or both. Service providers may use single or multiple technologies to deliver an end-to-end E-Tree service. Case 1: Single technology “Just VPLS” Case 2: Multiple technologies “VPLS + Others” Case 3: Single/multiple technologies “No VPLS” out of scope for this Internet draft A solution MUST identify which of the above cases the solution is applicable to. For Case 2, further details may be required to specify the applicable deployment scenarios. 9

10. Backward Compatibility A solution should minimise the impact on existing VPLS solution, especially for the MEF E-LAN services already in operation. A solution should be backward compatible with the existing VPLS solution. It should allow a case where a common VPLS instance is composed of both PEs supporting the solution and PEs not supporting it, and the Leaf-to-Leaf communication restriction is enforced within the scope of the compliant PEs. 10

11. VPMS and E-Tree IETF VPMS and MEF E-Tree are significantly different. The focus of VPMS is point-to-multipoint connectivity Single Root AC P2MP traffic from Root AC to all Leaf ACs Destination address not used in forwarding Optional, P2P traffic from Leaf AC to Root AC The focus of E-Tree is Leaf not communicate with Leaf Single or Multiple Roots Unicast/Broadcast/Multicast traffic as long as no Leaf-to-Leaf communication For generic E-Tree service, VPMS will not be able to meet the requirement. We have posted a message on the mailing list. 11

12. Are E-Tree requirements addressed in the VPMS requirement draft ? http://www.ietf.org/mail-archive/web/l2vpn/current/msg02433.html(14 July 2010) Quote from IETF 77 L2VPN WG minutes - Shane: really would like to see review of the drafts and to see if the ETREE requirements are addressed in the VPMS requirements draft. I would like to share my view with the working group. The focus of VPMS (Virtual Private Multicast Service) is to provide point-to-multipoint connectivity. VPMS provides single coverage of receiver membership. A VPMS service supports single Root AC. All traffic from the Root AC will be forwarded to all Leaf ACs (i.e. P2MP, from Root to all Leafs). Destination address in Ethernet frame is not used in data forwarding. As an optional capability, a VPMS service may support reverse traffic from a Leaf AC to the Root AC (i.e. P2P, from Leaf to Root). The focus of MEF E-Tree is that a Leaf can only communicate with Roots but not Leafs. A generic MEF E-Tree service supports multiple Root endpoints. Whether a particular E-Tree service needs to support single or multiple Root endpoints depends on the target application. A generic MEF E-Tree service supports all the following traffic flows: Ethernet Unicast bidirectional Root to/from Root Ethernet Unicast bidirectional Root to/from Leaf Ethernet Broadcast/Multicast unidirectional Root to all Roots & Leafs Ethernet Broadcast/Multicast unidirectional Leaf to all Roots. A particular E-Tree service may need to support all the above or only a subset depending on the target application. IETF's VPMS definition and MEF's E-Tree definition are significantly different. Only for special case E-Tree service where Single Root only No Unicast traffic from Root destined for a specific Leaf (or there is no concern if such Unicast traffic are forwarded to all Leafs), VPMS will be able to meet the requirement. An example is single-root E-Tree service for content delivery application. For generic E-Tree service, VPMS will not be able to meet the requirement. Thanks, Raymond Key 12

13. MEF E-Tree Support in VPLS We hope this Internet draft can facilitate a “solution-neutral” discussion on whether there is a valid requirement to enhance VPLS or not. We request this be adopted as a Working Group Draft. Please post questions and comments on the mailing list or talk/email to the authors direct. Thank you very much. 13