Networking Working Group Z. Liu Internet-Draft China Telecom Intended status: Informational L. Jin Expires: March 31, 2012 R. Chen ZTE September 28, 2011 Node redundancy provisioning for VPLS Inter-domain draft-liu-l2vpn-vpls-inter-domain-redundancy-01 Abstract In many VPLS deployment based on [RFC4762], inter-domain has been deployed without node redundancy, or only with node redundancy in one domain. This document describes how to deploy inter-domain VPLS based on [RFC4762] with node redundancy in both domain. The draft reuses the existing protocols without introducing any new protocols. 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 March 31, 2012. Copyright Notice 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. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of Liu, et al. Expires March 31, 2012 [Page 1] Internet-Draft Node redundancy for VPLS Inter-domain September 2011 the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Conventions used in this document . . . . . . . . . . . . . . . 3 3. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . 3 4. Redundancy scenario with ICCP . . . . . . . . . . . . . . . . . 3 5. Node redundancy for VPLS Inter-domain . . . . . . . . . . . . . 4 6. MAC Withdraw procedure . . . . . . . . . . . . . . . . . . . . 5 7. Load Balancing . . . . . . . . . . . . . . . . . . . . . . . . 6 8. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 9. Normative references . . . . . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7 Liu, et al. Expires March 31, 2012 [Page 2] Internet-Draft Node redundancy for VPLS Inter-domain September 2011 1. Introduction In many VPLS deployment based on [RFC 4762], inter-domain has been deployed without node redundancy, or only with node redundancy in one domain. This document describes how to deploy inter-domain VPLS based on [RFC 4762] with node redundancy in both domain. The draft reuses the existing protocols without introducing any new protocols. The domain in this document refers to AS, or other administrative domain. 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. Motivation Inter-AS VPLS has now been wildly deployed between two providers. Usually, the physical link and ASBR between the two providers would carry many kinds of service, then it is important to provider link and node redundancy for such kind of inter-AS service to ensure high availability. Some current high availability deployments of inter-AS VPLS are provided by MC-LAG (Multi-Chassis Link Aggregation) and [I-D.ietf-pwe3-iccp], but there is a pre-condition that the interconnected link between the two providers are Ethernet link. There are also many interconnection cases between two providers to use POS (Packet over Sonet/SDH) link on which MC-LAG cannot be enabled. Moreover, it is also required for the VPLS between two providers to ensure bandwidth control, QoS, MAC address control and Broadcast/Multicast traffic control. Then from the technical point of view, it is necessary to use PW to interconnect the two VPLS in its corresponding providers, and also to provide link/node redundancy to ensure high availability. 4. Redundancy scenario with ICCP The following figure presents a typical inter-AS VPLS deployment topology. PE3 and PE4 are the VPLS edge nodes in network of operator A, and PE5 and PE6 are the VPLS edge nodes in network of operator B. The PE3/PE4/PE5/PE6 may be ASBR of the AS, or VPLS PE within its own AS. Liu, et al. Expires March 31, 2012 [Page 3] Internet-Draft Node redundancy for VPLS Inter-domain September 2011 +---------+ +---------+ +---+ | +-----+ | active PW1 | +-----+| +---+ |PE1|---|-| PE3 |-|-----------------------|--| PE5 ||----|PE7| +---+\ |/+-----+ | | +-----+\ /+---+ | \ / | * | | * | |\ / | | \| | |ICCP| |ICCP| | | \ | | / \ | * | | * | |/ \ | +---+/ |\+-----+ | | +-----+/ \+---+ |PE2|---|-| PE4 |-|-----------------------|--| PE6 ||----|PE8| +---+ | +-----+ | standby PW2 | +-----+| +---+ | | | | | | | | | RG1 | | RG2 | +---------+ +---------+ operator A network operator B network Figure 1 When inter-AS VPLS is deployed with node redundancy on both AS side, node redundancy protocol ICCP[I-D.ietf-pwe3-iccp]SHOULD be implemented on the VPLS edge nodes of the AS, e.g, ICCP should be running between PE3 and PE4, PE5 and PE6. There are several deployment scenarios for inter-domain VPLS: o ICCP deployment option: ICCP is deployed on VPLS edge nodes in one domain, or in both domain; o PW redundancy mode: independent or master/slave; From the operator's point of view, it is important to keep the technical balance and technical independence between the two operators. One operator will not highly rely on the other operator's technical choice for inter-domain VPLS node redundancy. Then it is highly recommended to be the deployment scenario as follows: o ICCP deployment option: ICCP is deployed on VPLS edge nodes in both domain; o PW redundancy mode: independent only; And this draft will only focus on the above deployment option, other options are out of the scope. 5. Node redundancy for VPLS Inter-domain The PEs in the RG are required to run an inter-chassis communication protocol ([I-D.ietf-pwe3-iccp]) in order to select which pseudowire(s) should be in active/standby state for a given VPLS service instance. Liu, et al. Expires March 31, 2012 [Page 4] Internet-Draft Node redundancy for VPLS Inter-domain September 2011 The procedures to select active/standby pseudowire(s): o The PEs in the RG enable ICCP[I-D.ietf-pwe3-iccp]. o The PEs should establish a PW-RED application connection using the mechanism described in [I-D.ietf-pwe3-iccp], section 9.1.1. o When the PW-RED application connection first comes up, Each PE MUST advertise it local PW configuration to other PEs that are members of the same RG. As part of the configuration information, the PE should advertise a PW priority value that is used to determine the precedence of a given pseudowire. o Pseudowire Status Synchronization. A PE MAY re-advertise its PW- RED state in an unsolicited/solicited manner, the detailed mechanism is described in [I-D.ietf-pwe3-iccp], section 9.1.3. The PEs SHOULD then use PW redundancy bit [I-D.ietf-pwe3-redundancy-bit] or basic PW status bit [RFC4447] to advertise the outcome of the arbitration to the peer PE(s). Before deploying inter-domain VPLS, the operator MUST negotiate to configure same PW priority at two end-points. If different PW priority value is configured at the two PW end-points, e.g, PE3 and PE5 for PW1, and PE4 and PE6 for PW2 in figure 1, it is possible to select PE3 and PE6 as active for the two domain, then both PW1 and PW2 will be standby according to the independent mode in [I-D.ietf-pwe3-redundancy-bit]. 6. MAC Withdraw procedure It MAY be desirable to remove or unlearn MAC addresses that have been dynamically learned for faster convergence. This is accomplished by sending an LDP Address Withdraw Message. PE SHOULD not advertise MAC Address Withdraw message from one domain to the other. Correspondingly, VPLS PE that connects another domain SHOULD also reject any MAC Address Withdraw message received from that domain. The following will describe MAC Address Withdraw of VPLS Inter-AS in detail. When PE3 node failure and detecting that a remote PE3 that is member of the same RG, has got down, PE4 will send Address Withdraw Message with empty MAC list or positive MAC flush message [I-D.ietf-l2vpn-vpls-ldp-mac-opt] to other PEs that in the same AS(e.g.,PE2,PE3,and PE1), but will not send to PE6. The receiver PEs nodes flush the MAC addresses associated with corresponding VPLS instance. Upon detecting remote-end PE3 failure, PE5 will send negative MAC flush message [I-D.ietf-l2vpn-vpls-ldp-mac-opt] to other PEs that in the same AS(e.g., PE6, PE7, and PE8). The receiver PEs flush the MAC addresses associated with corresponding VPLS instance. When PW between PE3 and PE5 failure, PE3 and PE5 will only send negative MAC flush message to other PEs in its own AS. Liu, et al. Expires March 31, 2012 [Page 5] Internet-Draft Node redundancy for VPLS Inter-domain September 2011 7. Load Balancing It is recommended to configure different PW priority values for different VPLS instance, then the active PW of different VPLS will be running on different PEs, to provide load balancing between the two PE in one domain. +------------+ +------------+ +--------+ | +--------+ | | +--------+ | +--------+ | | | | PE3 | | | | PE5 | | | | | | | |+------+| | active PW1 | |+------+| | | | | | | ||VPLS_A||-|-------------| ||VPLS_A|| | | | | PE1 | | |+------+| | | |+------+| | | PE7 | | | | |+------+| | standby PW3 | |+------+| | | | | | | ||VPLS_B||-|-------------| ||VPLS_B|| | | | | |----|-|+------+| | | |+------+| | | | +--------+\ |/+--------+ | | +--------+\| /+--------+ | \ / | * | | * | \ / | | \/| | |ICCP | | ICCP| | |\/ | | /\| | | | | | | |/\ | | / \ | * | | * | / \ | +--------+/ |\+--------+ | | +--------+/| \+--------+ | |----|-| PE4 | | | | PE6 |-|----| | | | | |+------+| | standby PW2 | |+------+| | | | | | | ||VPLS_A||-|-------------| ||VPLS_A|| | | | | PE2 | | |+------+| | | |+------+| | | PE8 | | | | |+------+| | active PW4 | |+------+| | | | | | | ||vPLS_B||-|-------------| ||VPLS_B|| | | | | | | |+------+| | | |+------+| | | | +--------+ | +--------+ | | +--------+ | +--------+ +------------+ +------------+ operator A network operator B network Figure 2 In figure 2, it shows two VPLS inter-AS deployment. VPLS_A will have the PW between PE3 and PE5 with higher priority than the one between PE4 and PE6, while VPLS_B will have the PW between PE4 and PE6 with higher priority than the one between PE3 and PE5. Then PE3&PE4 or PE5&PE6 can provider load balance among different VPLS instance. 8. Security Considerations This section will be added in a future version. Liu, et al. Expires March 31, 2012 [Page 6] Internet-Draft Node redundancy for VPLS Inter-domain September 2011 9. Normative references [I-D.ietf-l2vpn-vpls-ldp-mac-opt] Dutta, P., Balus, F., Stokes, O., and G. Calvignac, "LDP Extensions for Optimized MAC Address Withdrawal in H-VPLS", draft-ietf-l2vpn-vpls-ldp-mac-opt-04 (work in progress), June 2011. [I-D.ietf-pwe3-iccp] Martini, L., Salam, S., Sajassi, A., Bocci, M., Matsushima, S., and T. Nadeau, "Inter-Chassis Communication Protocol for L2VPN PE Redundancy", draft-ietf-pwe3-iccp-05 (work in progress), April 2011. [I-D.ietf-pwe3-redundancy] Muley, P., Aissaoui, M., and M. Bocci, "Pseudowire Redundancy", draft-ietf-pwe3-redundancy-05 (work in progress), September 2011. [I-D.ietf-pwe3-redundancy-bit] Muley, P. and M. Aissaoui, "Pseudowire Preferential Forwarding Status Bit", draft-ietf-pwe3-redundancy-bit-05 (work in progress), September 2011. [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. [RFC4762] Lasserre, M. and V. Kompella, "Virtual Private LAN Service (VPLS) Using Label Distribution Protocol (LDP) Signaling", RFC 4762, January 2007. [RFC5036] Andersson, L., Minei, I., and B. Thomas, "LDP Specification", RFC 5036, October 2007. Liu, et al. Expires March 31, 2012 [Page 7] Internet-Draft Node redundancy for VPLS Inter-domain September 2011 Authors' Addresses Zhihua Liu China Telecom 109 Zhongshan Ave. Guangzhou 510630 P.R.China Email: zhliu@gsta.com Lizhong Jin ZTE Corporation 889 Bibo Road Shanghai 201203 P.R.China Email: lizhong.jin@zte.com.cn Ran Chen ZTE Corporation 68 Zijinghua Road Nanjing 210012 P.R.China Email: chen.ran@zte.com.cn Liu, et al. Expires March 31, 2012 [Page 8]