Networking Working Group R. Chen Internet-Draft ZTE Corporation Intended status: Standards Track March 21, 2012 Expires: September 22, 2012 Automatic VLAN allocation in E-tree draft-chen-l2vpn-vpls-etree-vlan-01 Abstract This document proposes to use automatically allocated VLAN ID to indicate E-Tree attribute. For the E-Tree requirement, please refer to [I-D.ietf-l2vpn-etree-reqt] for detail. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. 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." This Internet-Draft will expire on September 22, 2012. Copyright Notice Copyright (c) 2012 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. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Chen Expires September 22, 2012 [Page 1] Internet-Draft Automatic VLAN allocation in E-tree March 2012 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Conventions used in this document . . . . . . . . . . . . . . . 3 3. Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 4. Allocation mechanism . . . . . . . . . . . . . . . . . . . . . 4 5. Extension to LDP-VPLS for E-tree support . . . . . . . . . . . 5 6. Extension to BGP-VPLS for E-tree support . . . . . . . . . . . 6 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 8.1. Normative references . . . . . . . . . . . . . . . . . . . 7 8.2. Informative References . . . . . . . . . . . . . . . . . . 7 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 7 Chen Expires September 22, 2012 [Page 2] Internet-Draft Automatic VLAN allocation in E-tree March 2012 1. Introduction This document proposes to use automatically allocated VLAN ID to indicate E-Tree attribute. For the E-Tree requirement, please refer to [I-D.ietf-l2vpn-etree-reqt] for detail. In order to achieve better compatibility and traffic optimization, this document also introduces extensions to existing VPLS protocols as described in the document. 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 RFC2119. 3. Approach In order to be compatible with IEEE defined E-Tree, the approach in this draft uses the VLAN ID to indicate Root/Leaf attribute of the frame. There are two ways to manipulate VLANs for an E-Tree in VPLS: o Static configuring VLAN in IEEE, the Root/Leaf VLAN should co- ordinate manually or by management plane to be configured same on all the PEs in VPLS; o Unlike static configuring VLAN in IEEE, VPLS PE has the capability to create VLAN ID automatically, e.g. The VLAN ID can be derived from the PW type/AGI automatically via some algorithm; Regarding some VPLS PEs have single VLAN space without VLAN translation, and only support VLAN mapping to VPLS instance, and then if these PEs want to support VPLS E-tree, static configuring VLAN in IEEE would be used. Regarding some VPLS PEs support multiple VLAN spaces, then if these PEs want to support VPLS E-tree, an optimized approach would be used, which is automatic allocated VLAN. Unlike static configuring VLAN ID in IEEE, VPLS PE has the capability to create VLAN ID automatically, e.g. The VLAN ID can be derived from the PW type/AGI automatically via some algorithm. As part of VLAN auto-derive procedure, operators only need to configure the AC Leaf/Root properties, and not necessary to care about the exact VLAN number. One VLAN ID(Root VLAN ID) is used to indicate the frame originated from the Root AC and the other VLAN ID(Leaf VLAN ID) is used to indicate the frame originated from the Leaf AC between the pair of the PEs. Chen Expires September 22, 2012 [Page 3] Internet-Draft Automatic VLAN allocation in E-tree March 2012 <-----------------E-Tree-----------> +---------+ +---------+ | PE1 | | PE2 | +---+ | +----+ | | +----+ | +---+ |CE1|---AC1----|--| | | | | |-|----AC3---|CE3| +---+(Root AC) | | V | | Ethernet | | V | |(Root AC) +---+ | | S |-|------PW------| | S | | +---+ | | I | | | | I | | +---+ |CE2|---AC2----|--| | | | | |-|----AC4---|CE4| +---+(Leaf AC) | +----+ | | +----+ |(Leaf AC) +---+ +---------+ +---------+ Figure 1 As shown in figure 1, the VPLS PE1 and PE2 can both be attached with root/leaf AC, the VLANs which is used to indicate the Root/leaf can be derived from the PW type/AGI automatically. When PE1 receives a frame via the Root AC, PE1 can add the Root VLAN ID. When PE2 receives the frame from PE1 via the Ethernet PW, PE2 knows the frame originated from the Root, so it can forward the frame to AC3(Root AC) and AC4 (Leaf AC). When PE1 receives a frame via the Leaf AC, PE1 can add the leaf VLAN ID. When PE2 receives the frame from PE1 via the Ethernet PW, PE2 knows the frame originated from the Leaf, so it can forward the frame to AC3 (Root AC) but it must not be forwarded to any Leaf AC. The approach allows the egress PE to make a decision whether the frame can be forwarded or dropped towards a leaf AC. But in some special scenarios, e.g. one of the VPLS PE is attached with only leaves, some optimization should be done on the ingress PE to make a decision whether this frame should be forwarded or dropped. Such kind of mechanism can improve the bandwidth efficiency. The extension to VPLS for the PE attached with leaves only is defined in section 5. 4. Allocation mechanism As part of VLAN auto-derive procedure, each PE can only need to configure the Leaf/Root properties for each AC. Both the PWid FEC element and the Generalized PWid FEC Element can be used to set up the VPLS as defined in [RFC4762]. "MOD" operation is used to get Leaf/Root VLAN ID. In some chips, one VLAN space will not support all VLANs from 0~4094, then in order to make automatic allocated Chen Expires September 22, 2012 [Page 4] Internet-Draft Automatic VLAN allocation in E-tree March 2012 Root/Leaf VLANs be within the VLAN space, so we define this opertation. o Root ID = (ID) MOD (Maximum VLAN -Minimum VLAN)+Minimum VLAN + 1 + offset ; o Leaf ID = (ID) MOD (Maximum VLAN -Minimum VLAN)+Minimum VLAN + 2 + offset For the PWid FEC element, PW type could be used as the ID, then every PE in all VPLS instances obtains one pair of VLANs indicate Root VLAN, Leaf VLAN respectively. For the Generalized PWid FEC, AGI/PW type is used as ID, and AGI is defined in [RFC5003]. AGI as a VPLS ID would be the same at a particular VPLS instance, and every PE uses the same "mod" operation to obtain Leaf/Root VLAN from the VPLS ID. So every PE in the same VPLS instance obtains the same Root/Leaf VLAN. For the BGP-VPLS [RFC 4761], Import-RT+Export-RT could be used as ID. Import-RT+Export-RT would be same at a particular VPLS instance, and every PE uses the same "mod" operation to obtain Leaf/Root VLAN from the VPLS ID. So every PE in the same VPLS instance obtains the same Root/Leaf VLAN. 5. Extension to LDP-VPLS for E-tree support In addition to the signaling procedures for setting up PW as specified in RFC4447, one new PW interface parameter sub-TLV,the E-tree sub-TLV, is defined to use in E-Tree VPLS. The E-tree sub-TLV 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | E-tree (IANA) | Length | Reserved |P| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | offset | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2 In the above figure, reserved bit must be set to 0 when transmitting, and must be ignored upon receive. P bit is used to flag the PE which is attached with only leaves as follows: Chen Expires September 22, 2012 [Page 5] Internet-Draft Automatic VLAN allocation in E-tree March 2012 o P=1: the PE is attached with only leaves; o P=0: the PE is attached with roots and leaves or is attached with only roots. For offset, it should be 16-bit. It is configurable, if the operator uses different offset, it will lead some confusion. This TLV must be carried in label mapping message. If a PE supports E-tree service, it must send this E-tree sub-TLV and include its local offset value. A PE is attached with only leaves should set the P bit to 1. When a PE2 that received such a Label mapping message from its peer PE1, it knows that the PE1 has the E-tree capability. PE2 should check if the local configure match the offset value that carried in the Label mapping message, and if PE1 is attached with only leaves. 6. Extension to BGP-VPLS for E-tree support In addition to the signaling procedures for setting up PW as specified in [RFC4761], only a new extended community is defined to use in E-Tree VPLS. +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Extended community type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | offset | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved |P| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3 For offset, it should be 16-bit. It is configurable, if the operator uses different offset, it will lead some confusion. P is a Leaf-only bit, it is set to 1 to indicate that the PE is attached with only leaves, and set to 0 otherwise. In figure 1, when a PE2 receives BGP UPDATE message with an E-Tree Extended Community from its peer PE1, it knows that the PE1 has the E-tree capability.PE2 should check if the local configure match the TPID value that carried in the E-Tree Extended Community, and if PE1 is attached with only leaves. Chen Expires September 22, 2012 [Page 6] Internet-Draft Automatic VLAN allocation in E-tree March 2012 7. IANA Considerations This document creates a new interface parameter sub-TLV types (E-tree sub-TLV) that is allocated by IANA, and a value of 0X18 is suggested for assignment with this sub-TLV. 8. References 8.1. Normative references [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC4447] Martini, L., Rosen, E., El-Aawar, N., Smith, T., and G. Heron, "Pseudowire Setup and Maintenance Using the Label Distribution Protocol (LDP)", RFC 4447, April 2006. [RFC4761] Kompella, K. and Y. Rekhter, "Virtual Private LAN Service (VPLS) Using BGP for Auto-Discovery and Signaling", RFC 4761, January 2007. [RFC4762] Lasserre, M. and V. Kompella, "Virtual Private LAN Service (VPLS) Using Label Distribution Protocol (LDP) Signaling", RFC 4762, January 2007. [RFC5003] Metz, C., Martini, L., Balus, F., and J. Sugimoto, "Attachment Individual Identifier (AII) Types for Aggregation", RFC 5003, September 2007. 8.2. Informative References [I-D.ietf-l2vpn-etree-reqt] Key, R., Huang, L., Liu, Z., Paul, M., Kunze, R., Regno, N., and J. Rogers, "Requirements for MEF E-Tree Support in VPLS", draft-ietf-l2vpn-etree-reqt-00 (work in progress), October 2011. Chen Expires September 22, 2012 [Page 7] Internet-Draft Automatic VLAN allocation in E-tree March 2012 Author's Address Ran Chen ZTE Corporation NO.19 East Huayuan Road Haidian District Beijing 100191 P.R.China Email: chen.ran@zte.com.cn Chen Expires September 22, 2012 [Page 8]