Network Working Group R. Ram, Orckit-Corrigent Internet Draft D. Cohn, Orckit-Corrigent Category: Standard Track R. Key, Telstra P. Agarwal, Broadcom Expires: November 18, 2011 May 18, 2011 Extension to LDP-VPLS for E-Tree Using Two PW draft-ram-l2vpn-ldp-vpls-etree-2pw-02.txt Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. This document may not be modified, and derivative works of it may not be created, and it may not be published except as an Internet-Draft. This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. This document may not be modified, and derivative works of it may not be created, except to publish it as an RFC and to translate it into languages other than English. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html This Internet-Draft will expire in November 2011. Copyright Notice Ram, et al. November 2011 [Page 1] Internet-Draft Ext to LDP-VPLS for E-Tree 2-PW May 2011 Copyright (c) 2011 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Abstract This document proposes a solution for Metro Ethernet Forum (MEF) Ethernet Tree (E-Tree) support in Virtual Private LAN Service using LDP Signaling (LDP-VPLS) [RFC4762]. The proposed solution is characterized by the use of two PWs between a pair of PEs. This solution is applicable for both VPLS and H-VPLS. Table of Contents 1. Introduction ................................................... 3 2. Conventions used in this document............................... 3 3. The Problem .................................................... 3 4. The 2-PW Solution .............................................. 4 5. Extension to VPLS for E-Tree.................................... 5 5.1. AC E-Tree Type ......................................... 5 5.2. VSI E-Tree Type and Identifier.......................... 5 5.2.1. VSI E-Tree Type Encoding........................... 5 5.2.2. VSI E-Tree Identifier Encoding..................... 6 5.3. Additional Filtering in Data Forwarding................. 6 5.4. Root/Leaf PWs Signaling................................. 7 5.5. Supporting Remote AC.................................... 7 6. Backward Compatibility ......................................... 8 7. Compliance with Requirements.................................... 8 8. Security Considerations......................................... 8 9. IANA Considerations ............................................ 8 10. Acknowledgements .............................................. 8 11. References .................................................... 9 11.1. Normative References................................... 9 11.2. Informative References................................. 9 Ram et al Expires Nov 2011 [Page 2] Internet-Draft Ext to LDP-VPLS for E-Tree 2-PW May 2011 1. Introduction This document proposes a solution for Metro Ethernet Forum (MEF) Tree (E-Tree) support in Virtual Private LAN Service using LDP Signaling (LDP-VPLS) [RFC4762]. [Draft ETree VPLS Req] is used as requirement specification. The proposed solution is characterized by the use of two PWs between a pair of PEs, which requires extension to the current VPLS standard [RFC4762]. This solution is applicable for both VPLS and H-VPLS. The proposed solution is composed of three main components: - Current standard LDP-VPLS [RFC4762] - Extension to LDP-VPLS specified in this document - PE local split horizon mechanism 2. Conventions used in this document The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC-2119 [RFC2119]. In this document, these words will appear with that interpretation only when in ALL CAPS. Lower case uses of these words are not to be interpreted as carrying RFC-2119 significance. 3. The Problem [Draft ETree VPLS Req] identifies the problem when there are two or more PEs with both Root AC and Leaf AC. Ram et al Expires Nov 2011 [Page 3] Internet-Draft Ext to LDP-VPLS for E-Tree 2-PW May 2011 <-----------E-Tree----------> +---------+ +---------+ | PE1 | | PE2 | +---+ | +---+ | | +---+ | +---+ |CE1+----AC1----+--+ | | | | +--+----AC3----+CE3| +---+ (Root AC) | | V | | | | V | | (Root AC) +---+ | | S +--+--PW----+--+ S | | +---+ | | I | | | | I | | +---+ |CE2+----AC2----+--+ | | | | +--+----AC4----+CE4| +---+ (Leaf AC) | +---+ | | +---+ | (Leaf AC) +---+ +---------+ +---------+ Figure 1: Problem Scenario for Leaf-to-Leaf Communication Restriction When PE2 receives a frame from PE1 via the Ethernet PW, - PE2 does not know whether the ingress AC is a Leaf AC or not - PE2 does not have sufficient information to enforce the Leaf- to-Leaf communication restriction 4. The 2-PW Solution A simple fix is to carry additional information with each frame on the PW, indicating whether the frame is originated from a Leaf AC or a Root AC on the ingress PE. The proposed solution uses a pair of PWs to interconnect two VPLS PEs: o First PW is used for frames originated from Root ACs o Second PW is used for frames originated from Leaf ACs <--------------E-Tree--------------> +---------+ +---------+ | PE1 | | PE2 | +---+ | +---+ | | +---+ | +---+ |CE1+----AC1----+--+ | | | | +--+----AC3----+CE3| +---+ (Root AC) | | V +--+-VSI Root PW -+--+ V | | (Root AC) +---+ | | S | | | | S | | +---+ | | I +--+-VSI Leaf PW -+--+ I | | +---+ |CE2+----AC2----+--+ | | | | +--+----AC4----+CE4| +---+ (Leaf AC) | +---+ | | +---+ | (Leaf AC) +---+ +---------+ +---------+ Figure 2: Two-PW Solution for Leaf-to-Leaf Communication Restriction Ram et al Expires Nov 2011 [Page 4] Internet-Draft Ext to LDP-VPLS for E-Tree 2-PW May 2011 Extension to current VPLS standard [RFC4762] is required. 5. Extension to VPLS for E-Tree 5.1. AC E-Tree Type Each AC connected to a specific VPLS instance on a PE MUST have an AC E-Tree Type attribute, either Leaf AC or Root AC. For backward compatibility, the default AC E-Tree Type MUST be Root. This AC E-Tree Type is locally configured on a PE and no signaling is required between PEs. 5.2. VSI E-Tree Type and Identifier Two new PW interface parameters (as defined in section 5.5 of [RFC4447]) are defined for use in E-Tree VPLS: VSI E-Tree type and VSI E-Tree identifier. VSI E-Tree type can be either root or leaf and identifies VSI root PW and VSI leaf PW respectively, as defined in section 4. VSI E-tree identifier is a number that is used to identify a pair of root and leaf PW as part of the same logical VSI interface. On reception, the two PWs SHALL be handled as the same logical VSI interface with respect to MAC address learning/forwarding, e.g. traffic SHALL NOT be forwarded between such PWs and MAC addresses arriving at one of the PWs SHALL be learned with a common logical VSI interface. On transmission, the VPLS processing entity SHALL send root- originated traffic via the root PW, and SHALL send leaf-originated traffic via the leaf PW. The pair SHALL be unique in PWs connecting a pair of VPLS PEs. 5.2.1. VSI E-Tree Type Encoding The VSI E-Tree type field is encoded as an interface parameters sub- TLV (as defined in section 5.5 of [RFC4447]). The field structure is defined as follows: Ram et al Expires Nov 2011 [Page 5] Internet-Draft Ext to LDP-VPLS for E-Tree 2-PW May 2011 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type (TBD) | Length (1) | VSI E-Tree Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ VSI E-tree Type can take the following values: 0 E-Tree Root VSI 1 E-Tree Leaf VSI 5.2.2. VSI E-Tree Identifier Encoding The VSI E-Tree identifier field is encoded as an interface parameters sub-TLV (as defined in section 5.5 of [RFC4447]). The field structure is defined as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type (TBD) | Length (1) | VSI E-Tree Identifier | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | VSI E-Tree Identifier(cont.) | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ VSI E-tree Identifier is a 32-bit number that is used to identify a pair of root and leaf PW as part of the same logical VSI interface, in the context of a pair of VPLS PEs. The reserved field SHALL be set to zero. 5.3. Additional Filtering in Data Forwarding An egress PE SHALL NOT deliver a frame originated at a leaf AC to another leaf AC. The following specifies how AC E-Tree type per frame is determined: o A frame received from a root PW indicates that the frame was originated from a root AC o A frame received from a leaf PW indicates that the frame was originated from a leaf AC. Ram et al Expires Nov 2011 [Page 6] Internet-Draft Ext to LDP-VPLS for E-Tree 2-PW May 2011 o For the case where both ingress AC and egress AC are on the same PE, local split horizon implementation on the PE will be sufficient, and is not further discussed in this document. 5.4. Root/Leaf PWs Signaling Signaling of root and leaf PWs is required only when two PWs are used for interconnecting between pair of VSIs. As explained in section . 5.2. : o Root VSI E-Tree type SHALL be used to signal a root PW. o Leaf VSI E-Tree type be used to signal a leaf PW. PW type signaling rules remain as defined in [RFC4447]. 5.5. Supporting Remote AC When PW is used to interconnect between VSI and a remote AC (e.g. the PW1, PW2 in Figure 3), an Ethernet Raw or Ethernet tagged PW types SHALL be used as defined in [RFC4762]. <----------------------E-Tree----------> +-------+ +-------+ +----+ | PE1 | | PE2 | +---+ | | | +---+ | | +---+ | |CE1+---AC1---+----+PW1-+-+ | | | | | | +---+ +---+(Root AC)| | | | | | | | +-+---AC4---+CE4| |PE-r| | | V +-+VSI Root PW-+-+ V | |(Root AC)+---+ +---+ | | | | | | | | | | |CE2+---AC2---+----+PW2-+-+ S | | | | S | | +---+(Leaf AC)| | | | | | | | | | +----+ | | I +-+VSI Leaf PW-+-+ I | | +---+ | | | | | | | | +---+ |CE3+--------AC3--------+-+ | | | | +-+---AC5---+CE5| +---+ (Leaf AC) | +---+ | | +---+ |(Leaf AC)+---+ +-------+ +-------+ Figure 3: VPLS with Remote AC Connectivity In addition, the AC type i.e. Root or leaf, SHALL be locally provisioned on the VSI side to specify the remote AC E-Tree Type per PW. Moreover, such PWs that are used for interconnecting between a remote AC and a VSI SHALL considered as separate logical VSI interfaces with respect to MAC address learning/forwarding e.g. traffic forwarding between such PWs is allowed as long as they are not both defined as Leaf. Ram et al Expires Nov 2011 [Page 7] Internet-Draft Ext to LDP-VPLS for E-Tree 2-PW May 2011 In Figure 3, AC1 is remotely interconnected to the VPLS service via PW1, and AC2 is remotely interconnected to the VPLS service via PW2. AC1 is a Root AC and therefore the local type for PW1 in PE1 SHALL be Root. AC2 is a Leaf AC and therefore the local type for PW2 in PE1 SHALL be Leaf. 6. Backward Compatibility Root or leaf VSI E-Tree type and identifier parameters SHALL be used only in cases where both PEs are VPLS capable and both support E- Tree root/leaf. In a case where one of the peers do not support E-Tree, VSI E-Tree type and identifier parameters SHALL NOT be used. 7. Compliance with Requirements This refers to [Draft ETree VPLS Req] Section 5. Requirements. The solution prohibits communication between any two Leaf ACs in a VPLS instance. The solution allows multiple Root ACs in a VPLS instance. The solution allows Root AC and Leaf AC of a VPLS instance co-exist on any PE. The solution is applicable to LDP-VPLS [RFC4762]. The solution is applicable to Case 1: Single technology "VPLS Only". 8. Security Considerations This will be added in later version. 9. IANA Considerations Additional assignments will be required for the new interface parameter sub-TLV types introduced in Section 4.2. Details will be added in a later version. 10. Acknowledgements The authors wish to acknowledge the contributions of Luca Martini and Amir Halperin. Ram et al Expires Nov 2011 [Page 8] Internet-Draft Ext to LDP-VPLS for E-Tree 2-PW May 2011 11. References 11.1. Normative References [RFC2119] Bradner, S., Key words for use in RFCs to Indicate Requirement Levels, BCP 14, RFC 2119, March 1997. [RFC4447] Martini, L., and al, Pseudowire Setup and Maintenance Using the Label Distribution Protocol (LDP), April 2006 [RFC4762] Lasserre & Kompella, Virtual Private LAN Service (VPLS) Using Label Distribution Protocol (LDP) Signaling, January 2007 11.2. Informative References [Draft VPLS ETree Req] Key, et al., Requirements for MEF E-Tree Support in VPLS, draft-key-l2vpn-vpls-etree-reqt-01.txt, September 2010 Authors' Addresses Rafi Ram Orckit-Corrigent 126 Yigal Alon st. Tel Aviv, Israel Email: rafir@orckit.com Daniel Cohn Orckit-Corrigent 126 Yigal Alon st. Tel Aviv, Israel Email: danielc@orckit.com Raymond Key Telstra 242 Exhibition Street, Melbourne VIC 3000, Australia Email: raymond.key@team.telstra.com Puneet Agarwal Broadcom 3151 Zanker Road San Jose, CA 95134 Email: pagarwal@broadcom.com Ram et al Expires Nov 2011 [Page 9]