MPLS Working Group F. Zhang, Ed. Internet-Draft B. Wu, Ed. Intended status: Standards Track ZTE Corporation Expires: September 15, 2011 E. Bellagamba, Ed. Ericsson March 14, 2011 Label Distribution Protocol Extensions for Proactive Operations, Administration and Maintenance Configuration of Dynamic MPLS Transport Profile Pseudowire draft-zhang-mpls-tp-pw-oam-config-04 Abstract This document specifies extensions to the Label Distribution Protocal (LDP) to configure and control proactive Operations, Adminstration and Maintenance (OAM) functions, suitable for dynamic Single-Segment PseudoWire (SS-PW) and Multi-Segment PseudoWire (MS-PW). 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 15, 2011. 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 Zhang, et al. Expires September 15, 2011 [Page 1] Internet-Draft LDP Extensions for TP PW OAM March 2011 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. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Conventions used in this document . . . . . . . . . . . . . . 3 2.1. Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Analysis of Existing PW OAM Configuration . . . . . . . . . . 4 3.1. MPLS PW OAM Functions . . . . . . . . . . . . . . . . . . 4 3.2. Virtual Circuit Connectivity Verification . . . . . . . . 5 3.3. VCCV Bidirectional Forwarding Detection . . . . . . . . . 5 3.4. PW Status . . . . . . . . . . . . . . . . . . . . . . . . 5 3.5. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . 5 4. Analysis of PW OAM Configuration Extended by MPLS-TP . . . . . 6 4.1. Continuity Check, Connectivity Verification and Remote Defect Indication . . . . . . . . . . . . . . . . . . . . 6 4.2. Performance Monitoring Loss/Delay . . . . . . . . . . . . 7 4.3. FMS . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 4.4. On-demand OAM Functions . . . . . . . . . . . . . . . . . 8 4.5. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . 8 5. MPLS-TP PW OAM Capability Advertisement . . . . . . . . . . . 9 6. PW OAM Configurationd Procedures . . . . . . . . . . . . . . . 9 6.1. Establishment of OAM Entities and Functions . . . . . . . 9 6.2. Adjustment of OAM Parameters . . . . . . . . . . . . . . . 11 6.3. Deleting OAM Entities . . . . . . . . . . . . . . . . . . 12 7. LDP extensions . . . . . . . . . . . . . . . . . . . . . . . . 12 7.1. MPLS-TP PW OAM Capability TLV . . . . . . . . . . . . . . 12 7.2. MPLS-TP PW OAM Administration TLV . . . . . . . . . . . . 13 7.3. MPLS-TP PW OAM Configuration TLV . . . . . . . . . . . . . 14 7.3.1. BFD Configuration TLV . . . . . . . . . . . . . . . . 15 7.3.2. MPLS-TP PW PM Loss TLV . . . . . . . . . . . . . . . . 15 7.3.3. MPLS-TP PW PM Delay TLV . . . . . . . . . . . . . . . 15 7.3.4. MPLS-TP PW FMS TLV . . . . . . . . . . . . . . . . . . 16 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16 9. Security Considerations . . . . . . . . . . . . . . . . . . . 16 10. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 17 11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 17 11.1. Normative references . . . . . . . . . . . . . . . . . . . 17 11.2. Informative References . . . . . . . . . . . . . . . . . . 18 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 20 Zhang, et al. Expires September 15, 2011 [Page 2] Internet-Draft LDP Extensions for TP PW OAM March 2011 1. Introduction MPLS Pseudowire (PW) is defined in [RFC3985] and [RFC5659], which provide for emulated services over an MPLS Packet Switched Network (PSN). MPLS Transport Profile (MPLS-TP) describes a profile of MPLS that enables operational models typical in transport networks, while providing additional Operations, Administration and Maintenance (OAM), survivability and other maintenance functions not previously supported by IP/MPLS, including PW. The corresponding requirements are defined in [I-D.ietf-mpls-tp-oam-requirements]. The MPLS-TP OAM mechanisms that are operated to meet transport requirements are described in [I-D.ietf-mpls-tp-oam-framework], categorized into proactive and on-demand monitoring. Proactive monitoring refers to OAM operations that are either configured to be carried out periodically and continuously or preconfigured to act on certain events such as alarm signals. In contract, on-demand monitoring is initiated manually and for a limited amount of time, usually for operations such as diagnostics to investigate into a defect condition. The Network Management System (NMS) or Label Switched Path (LSP) Ping [I-D.ietf-mpls-lsp-ping-mpls-tp-oam-conf] is used to configure these OAM functionalities if a control plane is not instantiated. But if the control plane is used, it must support the configuration and modification of OAM maintenance points as well as the activation/ deactivation of OAM when the transport path or transport service is established or modified [RFC5654]. This document specifies extensions to the LDP protocol to negotiate PW OAM capabilities, configure and bootstrap proactive PW OAM functions, suitable for SS-PW and MS-PW, and Point to Multi-Point (P2MP) PW will be studied in the future. 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]. 2.1. Acronyms AC: Attachment Circuit Zhang, et al. Expires September 15, 2011 [Page 3] Internet-Draft LDP Extensions for TP PW OAM March 2011 AIS: Alarm indication signal BFD: Bidirectional Forwarding Detection CC: Continuity Check CV: Connectivity Verification DM: Delay Measurement FEC: Forwarding Equivalence Class FMS: Fault Management Signal ICMP: Internet Control Message Protocol LDI: Link Down Indication LDP: Label Distribution Protocol LKR: Lock Reporting LM: Loss Measurement LSP: Label Switched Path ME: Maintenance Entity MEG: Maintenance Entity Group MEP: Maintenance Entity Group End Point MIP: Maintenance Entity Group Intermediate Point MPLS-TP: MPLS Transport Profile MS-PW: Multi-Segment PseudoWire NMS: Network Management System OAM: Operations, Adminstration and Maintenance P2MP: Point to Multi-Point PE: Provider Edge PHB: Per-Hop Behavior PM: Performance Monitoring PSN: Packet Switched Network PW: PseudoWire S-PE: Switching Provider Edge SPME: Sub-path Maintenance Entity SS-PW: Single-Segment Pseudo Wire T-PE: Terminating Provider Edge TLV: Type Length Value VCCV: Virtual Circuit Connectivity Verification 3. Analysis of Existing PW OAM Configuration 3.1. MPLS PW OAM Functions Before MPLS-TP standards, PW OAM functions have been implemented by [RFC5085], [RFC5885], [RFC4447] and [I-D.ietf-pwe3-static-pw-status]. [RFC5085] defines Connectivity Verification (CV), which belongs to on-demand PW monitoring. [RFC5885] defines proactive Continuity Check (CC), as well as PW and Attachemnt Circuit (AC) status notification. [RFC4447] and [I-D.ietf-pwe3-static-pw-status] give some other ways of PW/AC status notification. Zhang, et al. Expires September 15, 2011 [Page 4] Internet-Draft LDP Extensions for TP PW OAM March 2011 3.2. Virtual Circuit Connectivity Verification The goal of Virtual Circuit Connectivity Verification (VCCV) is to verify and further diagnose PW forwarding path, and the extensions of [RFC5085] to LDP are to signal VCCV capabilities to a peer Provider Edge (PE). 3.3. VCCV Bidirectional Forwarding Detection Four CV types for Bidirectional Forwarding Detection (BFD) by combining two types of encapsulation with two types of functionality are specified in [RFC5885]. When multiple BFD CV Types are advertised, it also describes how to select one to use. The extension of [RFC5885] to LDP are to signal VCCV BFD capabilities to a peer PE, and activate BFD protocol after PW is established. If the BFD parameters (such as sending interval) need to be modified, BFD itself will handle it. 3.4. PW Status PW status codes provide a mechanism to signal the status of PW and AC failure. When PW control plane exists, the PW Status TLV is carried in the initial Label Mapping message and Notification message to signal all PW status messages. The OAM related extensions of [RFC4447] to LDP are to signal PW Status TLV to a peer PE, and activate PW status notification function after PW is established. So when an event occurs, an update PW status will be sent. 3.5. Conclusion In summary, IP/MPLS PW OAM functions and relation with control plane/ NMS is described in table 1. This document will not replace or deprecate these (e.g., VCCV capability advertisement and PW status negotiation for MPLS networks). Zhang, et al. Expires September 15, 2011 [Page 5] Internet-Draft LDP Extensions for TP PW OAM March 2011 |----------------------------------------------------------------------| | | | LDP | LSP Ping | NMS | |----------------------------------------------------------------------| | | VCCV | Capability | | Capability | | | LSP ping | negotiation | |configuration&| | On-demand | | | | Bootstrapping| | MPLS PW |-------------------------------------------------------| | OAM | VCCV | Capability | | Capability | | | ICMP ping | negotiation | |configuration&| | | | | | Bootstrapping| |----------------------------------------------------------------------| | | VCCV BFD | Capability | | Capability | | | | negotiation& | |configuration&| | | | Bootstrapping| | Bootstrapping| | Proactive |-------------------------------------------------------| | OAM | PW status | Capability | | Capability | | | | negotiation& | |configuration&| | | | Bootstrapping| | Bootstrapping| |----------------------------------------------------------------------| Table 1: IP/MPLS PW OAM Functions 4. Analysis of PW OAM Configuration Extended by MPLS-TP 4.1. Continuity Check, Connectivity Verification and Remote Defect Indication The Proactive CC, CV and Remote Defect Indication (RDI) functions of MPLS-TP are based on the extensions to BFD, see[I-D.ietf-mpls-tp-cc-cv-rdi]. Because VCCV BFD currently has no CV function, it SHOULD evolve with [I-D.ietf-mpls-tp-cc-cv-rdi] to provide this function in MPLS-TP environment. The use of the VCCV control channel provides the context, based on the MPLS-PW label, required to bind and bootstrap the BFD session to a particular PW, so local discriminator values are not exchanged; please refer to the analysis in [I-D.ietf-mpls-tp-oam-analysis] and [RFC5885]. However, in order to identify certain extreme cases of mis-connectivity and fulfill the requirements that the BFD mechanism MUST be the same for LSP, Single Segment Pseudowire (SS-PW), Multi Segment Pseudowire (MS-PW) and Section as well as for Sub-path Maintenance Element (SPME), BFD might still need to use discriminator values to identify the connection being verified at both ends of the PW. The discriminator values can be statically configured, or signaled via LSP Ping or LDP extensions defined in this document. Timer negotiation, such as Transmitter (TX)/Receiver (RX) interval is Zhang, et al. Expires September 15, 2011 [Page 6] Internet-Draft LDP Extensions for TP PW OAM March 2011 performed in subsequent BFD control messages [RFC5880], but it also can be gotten by control plane signaling [I-D.ietf-mpls-tp-oam-framework]. The source Maintenance Entity Group End Point Identifier (MEP-ID) does not need to be carried, for they can be deduced from the advertised FEC (129) TLV, as described in [I-D.ietf-mpls-tp-identifiers]. Per-hop Behavior (PHB), which identifies the per-hop behavior of BFD packet, SHOULD be configured as well. This permits the verification of correct operation of Quality of Serivce (QoS) queuing as well as connectivity. In conclusion, the configuration of VCCV BFD by control plane is not necessary, but for consistent operation of transport path and section, it SHOULD be an option. 4.2. Performance Monitoring Loss/Delay Performance monitoring (PM) of PWs, especially for packet Loss Measurement (LM) and packet Delay Measurement (DM), are specified in [I-D.ietf-mpls-loss-delay], [I-D.ietf-mpls-tp-loss-delay-profile]. For proactive LM, the transmission rate and PHB associated with the LM OAM packets originating from a MEP need be negotiated with the other MEP. LM OAM packets should be transmitted with the same PHB class that the LM is intended to measure. Just like LM, Both one way and two way mode of proactive DM need the two MEPs nodes of PW to negotiate the measure interval and PHB value of OAM packets. 4.3. FMS Fault Management Signals (FMS) are specified in [I-D.ietf-mpls-tp-fault], with which a server PW can notify client PWs about various fault conditions to suppress alarms or to be used as triggers for actions in the client PWs. The following signals are defined: Alarm Indication Signal (AIS), Link Down Indication (LDI) and Lock Reporting (LKR). For each MEP of each Maintenance Entity Group (MEG), enabling/ disabling the generation of FMS packets, the transmitted period and PHB SHOULD be configured. This can be done independently, and the values of configured parameters can be different, but for easy maintenance, these setting SHOULD be consistent. Zhang, et al. Expires September 15, 2011 [Page 7] Internet-Draft LDP Extensions for TP PW OAM March 2011 In conclusion, the configuration of FMS by control plane is not necessary, but for easy maintenance, it SHOULD be an option also. 4.4. On-demand OAM Functions The extended on-demand OAM functions MAY need capability negotiation in the LDP Initialization message [RFC5561]. However, On-demand PW OAM functions are expected to be carried out by directly accessing network nodes via a management interface; hence configuration and control of on-demand PW OAM functions are out-of-scope for this document. 4.5. Conclusion According to the analysis above, LDP needs to be extended to negotiate PW OAM capabilities, configure and bootstrap proactive PW OAM functions, such as, CC-CV-RDI, PM Loss/Delay, FMS. In this way OAM setup is bound to connection establishment signaling, avoiding two separate management/configuration steps (connection setup followed by OAM configuration) which would increases delay, processing and more importantly may be prune to mis-configuration errors. Furthermore, LSP ping can be used to configure the proactive PW OAM function extended by MPLS-TP also, suitable for dynamic and static PW. For reference, the following table 2 describes the different scope of different proactive OAM bootstrapping schemes of dynamic PW. |-------------------------------------------------------------------------| | | | LDP | LSP Ping | NMS | |-------------------------------------------------------------------------| | | |Capability | | Capability | | | |negotiation& | |configuration&| | | CC/CV/RDI |Function | Function | Function | | | |configuration&|configuration&|configuration&| | | |Bootstrapping |Bootstrapping | Bootstrapping| | |------------------------------------------------------------| | Proactive | |Capability | | Capability | | OAM | |negotiation& | |configuration&| | | FMS |Function | Function | Function | | | |configuration&|configuration&|configuration&| | | |Bootstrapping |Bootstrapping | Bootstrapping| | |------------------------------------------------------------| | | |Capability | | Capability | | | |negotiation& | |configuration&| | | PM Loss/Delay |Function | Function | Function | Zhang, et al. Expires September 15, 2011 [Page 8] Internet-Draft LDP Extensions for TP PW OAM March 2011 | | |configuration&|configuration&|configuration&| | | |Bootstrapping |Bootstrapping | Bootstrapping| |------------|------------------------------------------------------------| Table 2: MPLS-TP PW OAM Functions 5. MPLS-TP PW OAM Capability Advertisement When a PW is first set up, the PEs MUST attempt to negotiate the usage of OAM functions. At the time of writing this specification, there are PW status negotiation and VCCV capability advertisement. For the proactive OAM functions as extended to support by MPLS-TP, such as CC-CV-RDI, PM loss/delay and FMS, the capability negotiation MAY be also needed, so a PE that supports the MPLS-TP PW OAM capability MUST include MPLS-TP PW OAM Capability TLV in the LDP Initialization message. And if the peer has not advertised this capability, the corresponding PW OAM configuration information will not be sent to the peer. 6. PW OAM Configurationd Procedures A PE may play an active or passive role in the signaling of the PW. There exist two situations: a) Active/active "C Both PEs of a PW are active (SS-PW), they select PW OAM configuration parameters and send with the Label Mapping message to each other independently. b) Active/passive "C One PE is active and the others are passive (MS-PW). The active/passive role election is defined in Section 7.2.1 of [I-D.ietf-pwe3-segmented-pw] and applies here, this document does not define any new role election procedures. The general rules of OAM configuration procedures are mostly identical between MS-PW and SS-PW, except that SS-PW does not need to configure MIP function and the Mapping message are sent out independently. This section takes MS-PW as an example to describe the general OAM configuration procedures. As for SS-PW, there may be some collisions of PW OAM configuration parameters, and these specific differences would be addressed in section 6. 6.1. Establishment of OAM Entities and Functions Assuming there is one PW that needs to be setup between T-PE1 and T-PE2, across S-PE1 and S-PE2. OAM functions must be setup and Zhang, et al. Expires September 15, 2011 [Page 9] Internet-Draft LDP Extensions for TP PW OAM March 2011 enabled in the appropriate order so that spurious alarms can be avoided. +-------+ +-------+ +-------+ +-------+ | | | | | | | | | A|--------|B C|--------|D E|--------|F | | | | | | | | | +-------+ +-------+ +-------+ +-------+ T-PE1 S-PE1 S-PE2 T-PE2 Figure 1: MS-PW OAM Configuration Scheme Fist of all, T-PE1 MUST setup the OAM sink function to be prepared to receive OAM messages but MUST suppress any OAM alarms (e.g., due to missing or unidentified OAM messages). The Mapping message MUST be sent with the "OAM Alarms Enabled" cleared, "OAM MEP Entities desired" set and "OAM MIP Entities desired" set in the MPLS-TP PW OAM Administation TLV. When the Mapping message arrives at the downstream receivers, such as S-PE1, S-PE2 and T-PE2, they MUST establish and configure OAM entities according to the OAM information provided in mapping message. If this is not possible, a Notification message SHOULD be sent and neither the OAM entities nor the PW SHOULD be established. If OAM entities are established successfully, the middle points (S-PE1 and S-PE2) MUST forward the Mapping message downstream, the endpoint (T-PE2) MUST set the OAM Source function and MUST be prepared to Send OAM messages. The same rules are applied to the reverse direction (from T-PE2 to T-PE1), that is to say, T-PE2 needs to setup the OAM sink function to be prepared to receive OAM messages but MUST suppress any OAM alarms (e.g., due to missing or unidentified OAM messages). The Mapping message MUST be sent with the "OAM Alarms Enabled" cleared, "OAM MEP Entities desired" set, "OAM MIP Entities desired" set in the MPLS-TP PW OAM Administration TLV. When T-PE1 receives the Mapping message, it completes any pending OAM configuration and enables the OAM source function to send OAM messages. After this round, OAM entities are established and configured for the PW and OAM messages MAY already be exchanged, and OAM alarms can now be enabled. The T-PE nodes(T-PE1 and T-PE2), while still keeping OAM alarms disabled send a Notification message with "OAM Alarms Enabled" PW status flag set, and enable the OAM alarms after processing the Notification message. At this point, data-plane OAM is fully functional, and the MPLS-TP OAM PW configuration TLV MAY be omitted in subsequent Notification messages Zhang, et al. Expires September 15, 2011 [Page 10] Internet-Draft LDP Extensions for TP PW OAM March 2011 The PW MAY be setup with OAM entities right away with the first signaling, as described above, but a PW MAY be signaled and established without OAM configuration first, and OAM entities may be added later. This can be done by sending a Notification message with the related configuration parameters subsequently. 6.2. Adjustment of OAM Parameters There may be a need to change the parameters of an already established and configured OAM function during the lifetime of the PW. To do so the T-PE nodes need to send a Notification message with the updated parameters. OAM parameters that influence the content and timing of OAM messages and identify the way OAM defects and alarms are derived and generated. Hence, to avoid spurious alarms, it is important that both sides, OAM sink and source, are updated in a synchronized way. First, the alarms of the OAM sink function should be suppressed and only then should expected OAM parameters be adjusted. Subsequently, the parameters of the OAM source function can be updated. Finally, the alarms of the OAM sink side can be enabled again. In accordance with the above operation, T-PE1 MUST send a Notification message with "OAM Alarms Enabled" cleared and including the updated MPLS-TP PW OAM Configuration TLV corresponding to the new parameter settings. The initiator (T-PE1) MUST keep its OAM sink and source functions running unmodified, but it MUST suppress OAM alarms after the updated Notification message is sent. The receiver (T-PE2) MUST first disable all OAM alarms, then update the OAM parameters according to the information in the Notification message and reply with a Notification message acknowledging the changes by including the MPLS-TP PW OAM Configuration TLV. Note that the receiving side has the possibility to adjust the requested OAM configuration parameters and reply with and updated MPLS-TP PW OAM Configuration TLV in the Notification message, reflecting the actually configured values. However, in order to avoid an extensive negotiation phase, in the case of adjusting already configured OAM functions, the receiving side SHOULD NOT update the parameters requested in the Notification message to an extent that would provide lower performance than what has been configured previously. The initiator (T-PE1) MUST only update its OAM sink and source functions when it has received the Notification message from the peer. After the OAM parameters are updated and OAM is running according the new parameter settings, OAM alarms are still disabled, so a subsequent Notification messages exchanges with "OAM Alarms Enabled" flag set are needed to enable OAM alarms again. Zhang, et al. Expires September 15, 2011 [Page 11] Internet-Draft LDP Extensions for TP PW OAM March 2011 6.3. Deleting OAM Entities In some cases it may be useful to remove some or all OAM entities and functions from one PW without actually tearing down the connection. To avoid any spurious alarm, the following procedure should be followed: The T-PE nodes disable OAM alarms and SHOULD send Notification message to each other with "OAM Alarms Enabled" cleared but unchanged OAM configuration and without the MPLS-TP PW OAM Configuration TLV. After that, T-PE1 (T-PE2) SHOULD delete OAM source functions, then send a Notification message with "OAM MEP Entities desired" and "OAM MIP Entities desired" cleared. While T-PE2 (T-PE1) deletes OAM sink function when it receives the Notification message with "OAM MEP Entities desired" cleared, S-PE1 and S-PE2 delete MIP configuration when they receive the Notification message with "OAM MIP Entities desired" cleared. Alternatively, if only some OAM functions need to be removed, the T-PE node sends the Notification message with the updated OAM Configuration TLV. Changes between the contents of the previously signaled OAM Configuration TLV and the currently received TLV represent which functions SHOULD be removed/added. 7. LDP extensions Below, LDP extensions to configure proactive MPLS-TP PW OAM functions are defined. 7.1. MPLS-TP PW OAM Capability TLV A new Capability Parameter TLV called the MPLS-TP PW OAM Capability TLV is defined, and the format is 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1|0| Type (TBD) | Length (= 4) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1| Reserved | Reserved |F|D|L| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ MPLS-TP PW OAM Capability TLV The value of the U-bit for the MPLS-TP PW OAM Capability TLV MUST be set to 1 so that a receiver MUST silently ignore this TLV if unknown to it, and continue processing the rest of the message. Currently Zhang, et al. Expires September 15, 2011 [Page 12] Internet-Draft LDP Extensions for TP PW OAM March 2011 defined specific OAM Capability Flags in the "Capability Data" field from right to left are: One bit "L" (0, IANA to assign) PM Loss supported One bit "D" (1, IANA to assign) PM Delay supported One bit "F" (2, IANA to assign) FMS supported The above bits can be set individually to indicate more than one kind of OAM capabilities at once, and the other reserved bits MUST be set to zero on transmission and MUST be ignored on receipt. The MPLS-TP PW OAM Capability TLV MAY be included by a PE in an Initialization message to signal its peer that it supports the MPLS-TP PW OAM Capability. If the remote peer does not support the MPLS-TP PW OAM Capability TLV or the Initialization message sent by the remote peer does not include the MPLS-TP PW OAM Capability TLV, which indicates that the negotiation results do not support MPLS-TP PW OAM capability. If the negotiation process results support the MPLS-TP PW OAM capability, then the subsequent LDP Mapping message will carry the information of the MPLS-TP PW OAM configuration. 7.2. MPLS-TP PW OAM Administration TLV The format of the MPLS-TP PW OAM Administration TLV is 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|0| Type (TBD) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |E|I|A| Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ MPLS-TP PW OAM Administration TLV One bit "E" (31, IANA to assign): "OAM MEP entities desired" is allocated. If the "OAM MEP entities desired" bit is set it is indicating that the establishment of OAM MEP entities are required at the endpoints of the signaled PW. If the establishment of MEPs is not supported, a Notification message MUST be sent. If the "OAM MEP entities desired" bit is set and additional parameters are needed to be configured on the OAM entities, an "MPLS-TP PW OAM Configuration TLV" may be included in the Mapping or Notification message. One bit "I" (30, IANA to assign): "OAM MIP entities desired" is allocated. This bit can only be set if the "OAM MEP entities Zhang, et al. Expires September 15, 2011 [Page 13] Internet-Draft LDP Extensions for TP PW OAM March 2011 desired" bit is set. If the "OAM MIP entities desired" bit is set, it is indicating that the establishment of OAM MIP entities is required at every transit node of the signaled PW. If the establishment of a MIP is not supported, a Notification message MUST be sent. One bit "A" (29, IANA to assign): "OAM Alarms Enabled" is allocated. This bit can only be set if the "OAM MEP entities desired" bit is set. If the "OAM Alarms Enabled" bit is set, it is indicating that the T-PE needs to enable OAM alarms. If the establishment of a MIP is not supported, a Notification message MUST be sent. Reserved (29bits): This field MUST be set to zero on transmission and MUST be ignored on receipt. 7.3. MPLS-TP PW OAM Configuration TLV The "OAM Configuration TLV", defined in [I-D.ietf-ccamp-oam-configuration-fwk], is depicted in the following figure. It may be carried in the Mapping and Notification messages, just following the PW Status TLV. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|0| Type (TBD) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | OAM Type | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | ~ sub-TLVs ~ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ MPLS-TP PW OAM Configuration TLV OAM type: indicates a new type: the MPLS-TP PW OAM Configuration TLV (IANA to assign). If this type is not supported, a Notification message MUST be sent. The specific OAM functions are specified in the "Function Flags" sub-TLV as depicted in [I-D.ietf-ccamp-oam-configuration-fwk], and the additional corresponding sub-TLVs are defined in section 3.2 of [I-D.ietf-ccamp-rsvp-te-mpls-tp-oam-ext]. For active/active signaling, if the flags in the "MPLS-TP PW OAM Function Flags sub-TLV" are different in the two Mapping message, the two PEs nodes can compare the node IDs. Label Withdraw message MUST be sent by the PE with lower ID, then it sends the Label Mapping Zhang, et al. Expires September 15, 2011 [Page 14] Internet-Draft LDP Extensions for TP PW OAM March 2011 message again with the same flags carried in the received Label Mapping message. 7.3.1. BFD Configuration TLV BFD Configuration TLV follows the same TLV structure defined for Resource ReSerVation Protocol Traffic Engineering (RSVP-TE) in section 3.3 of [I-D.ietf-ccamp-rsvp-te-mpls-tp-oam-ext]. For active/active signaling, if the flags of "BFD Configuration TLV" are different in the two Mapping message, similarly Label Withdraw message MUST be sent by the PE with lower identifier. Then it sends the Label Mapping message again with the same flags carried in the "BFD configuration TLV" of the received Label Mapping message. If the flags of "BFD Configuration TLV" are the same, but the values of "Negotiation Timer parameters sub-TLV" are different, both the PE nodes MUST adopt the bigger interval and detection time multiplier. 7.3.2. MPLS-TP PW PM Loss TLV MPLS-TP PW PM Loss TLV follows the same TLV structure defined for RSVP-TE in section 3.4 of [I-D.ietf-ccamp-rsvp-te-mpls-tp-oam-ext]. For active/active signaling, if the flags of "MPLS-TP PW OAM PM Loss TLV" are different in the two Mapping message, similarly Label Withdraw message MUST be sent by the PE with lower ID. Then it sends the Label Mapping message again with the same flags carried in the "MPLS-TP PW OAM PM Loss TLV" of the received Label Mapping message. If the flags of "MPLS-TP PW OAM PM Loss TLV" are the same, but the Measurement Interval and Loss Threshold are different, both the PE nodes MUST adopt the bigger values. 7.3.3. MPLS-TP PW PM Delay TLV MPLS-TP PW PM Delay TLV follows the same TLV structure defined for RSVP-TE in section 3.5 of [I-D.ietf-ccamp-rsvp-te-mpls-tp-oam-ext]. For active/active signaling, if the flags of "MPLS-TP PW OAM PM Delay TLV" are different in the two Mapping message, similarly Label Withdraw message MUST be sent by the PE with lower ID. Then it sends the Label Mapping message again with the same flags carried in the "MPLS-TP PW OAM PM Delay TLV" of the received Label Mapping message. If the flags of "MPLS-TP PW OAM PM Delay TLV" are the same, but the Measurement Interval and Delay Threshold are different, both the PE nodes MUST adopt the bigger values. Zhang, et al. Expires September 15, 2011 [Page 15] Internet-Draft LDP Extensions for TP PW OAM March 2011 7.3.4. MPLS-TP PW FMS TLV MPLS-TP PW FMS TLV follows the same TLV structure defined for RSVP-TE in section 3.6 of [I-D.ietf-ccamp-rsvp-te-mpls-tp-oam-ext]. For active/active signaling, if the flags of "MPLS-TP PW OAM FMS TLV" are different in the two Mapping message, similarly Label Withdraw message MUST be sent by the PE with lower ID. Then it sends the Label Mapping message again with the same flags carried in the "MPLS-TP PW OAM FMS TLV" of the received Label Mapping message. Notes: Client Signal Fail (CSF) are overlapped with PW Status TLV, and the field of Refresh Timer is not needed. 8. IANA Considerations This document specifies the following new LDP TLV types: o MPLS-TP PW OAM Capability TLV; o MPLS-TP PW OAM Administration TLV; o MPLS-TP PW OAM Configuration TLV; Sub-TLV types to be carried in the "MPLS-TP PW OAM Configuration TLV": o MPLS-TP PW OAM Function Flags sub-TLV; o BFD Configuration sub-TLV; o MPLS-TP PW PM Loss sub-TLV; o MPLS-TP PW PM Delay sub-TLV; o MPLS-TP PW FMS sub-TLV; Sub-TLV types to be carried in the "BFD Configuration sub-TLV": o Local Discriminator sub-TLV; o Negotiation Timer Parameters sub-TLV. o BFD Authentication sub-TLV 9. Security Considerations Security considerations relating to LDP are described in section 5 of [RFC5036] and section 11 of [RFC5561]. Security considerations relating to use of LDP in setting up PWs is described in section 8 of [RFC4447]. This document defines new TLV/sub-TLV types, and OAM configuration procedures intended for use with MPLS-TP, which do not raise any additional security issues. Zhang, et al. Expires September 15, 2011 [Page 16] Internet-Draft LDP Extensions for TP PW OAM March 2011 10. Acknowledgement The authors would like to thank Thomas Nadeau for his valuable comments, Eric Gray for his review of this document. 11. References 11.1. Normative references [I-D.ietf-ccamp-oam-configuration-fwk] Takacs, A., Fedyk, D., and H. Jia, "GMPLS RSVP-TE extensions for OAM Configuration", draft-ietf-ccamp-oam-configuration-fwk-04 (work in progress), October 2010. [I-D.ietf-ccamp-rsvp-te-mpls-tp-oam-ext] Bellagamba, E., Andersson, L., Skoldstrom, P., Ward, D., and A. Takacs, "Configuration of pro-active MPLS-TP Operations, Administration, and Maintenance (OAM) Functions Using RSVP-TE", draft-ietf-ccamp-rsvp-te-mpls-tp-oam-ext-05 (work in progress), March 2011. [I-D.ietf-mpls-lsp-ping-mpls-tp-oam-conf] Bellagamba, E., Andersson, L., Skoldstrom, P., Ward, D., and J. Drake, "Configuration of pro-active MPLS-TP Operations, Administration, and Maintenance (OAM) Functions Using LSP Ping", draft-ietf-mpls-lsp-ping-mpls-tp-oam-conf-01 (work in progress), March 2011. [I-D.ietf-mpls-tp-oam-framework] Allan, D., Busi, I., Niven-Jenkins, B., Fulignoli, A., Hernandez-Valencia, E., Levrau, L., Sestito, V., Sprecher, N., Helvoort, H., Vigoureux, M., Weingarten, Y., and R. Winter, "Operations, Administration and Maintenance Framework for MPLS-based Transport Networks", draft-ietf-mpls-tp-oam-framework-11 (work in progress), February 2011. [I-D.ietf-mpls-tp-oam-requirements] Vigoureux, M. and D. Ward, "Requirements for OAM in MPLS Transport Networks", draft-ietf-mpls-tp-oam-requirements-06 (work in progress), March 2010. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Zhang, et al. Expires September 15, 2011 [Page 17] Internet-Draft LDP Extensions for TP PW OAM March 2011 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. [RFC5003] Metz, C., Martini, L., Balus, F., and J. Sugimoto, "Attachment Individual Identifier (AII) Types for Aggregation", RFC 5003, September 2007. [RFC5085] Nadeau, T. and C. Pignataro, "Pseudowire Virtual Circuit Connectivity Verification (VCCV): A Control Channel for Pseudowires", RFC 5085, December 2007. 11.2. Informative References [I-D.ietf-mpls-loss-delay] Frost, D. and S. Bryant, "Packet Loss and Delay Measurement for MPLS Networks", draft-ietf-mpls-loss-delay-01 (work in progress), February 2011. [I-D.ietf-mpls-tp-cc-cv-rdi] Allan, D., Drake, J., Swallow, G., Boutros, S., Sivabalan, S., and D. Ward, "Proactive Connectivity Verification, Continuity Check and Remote Defect indication for MPLS Transport Profile", draft-ietf-mpls-tp-cc-cv-rdi-03 (work in progress), February 2011. [I-D.ietf-mpls-tp-fault] Swallow, G., Fulignoli, A., Vigoureux, M., Boutros, S., Ward, D., Bryant, S., and S. Sivabalan, "MPLS Fault Management OAM", draft-ietf-mpls-tp-fault-03 (work in progress), October 2010. [I-D.ietf-mpls-tp-identifiers] Bocci, M., Swallow, G., and E. Gray, "MPLS-TP Identifiers", draft-ietf-mpls-tp-identifiers-04 (work in progress), March 2011. [I-D.ietf-mpls-tp-loss-delay-profile] Frost, D. and S. Bryant, "A Packet Loss and Delay Measurement Profile for MPLS-based Transport Networks", draft-ietf-mpls-tp-loss-delay-profile-02 (work in progress), February 2011. [I-D.ietf-mpls-tp-lsp-ping-bfd-procedures] Bahadur, N., Aggarwal, R., Ward, D., Nadeau, T., Sprecher, Zhang, et al. Expires September 15, 2011 [Page 18] Internet-Draft LDP Extensions for TP PW OAM March 2011 N., and Y. Weingarten, "LSP-Ping and BFD encapsulation over ACH", draft-ietf-mpls-tp-lsp-ping-bfd-procedures-01 (work in progress), August 2010. [I-D.ietf-mpls-tp-oam-analysis] Sprecher, N., Bellagamba, E., and Y. Weingarten, "OAM functions in MPLS based transport network", draft-ietf-mpls-tp-oam-analysis-03 (work in progress), January 2011. [I-D.ietf-pwe3-dynamic-ms-pw] Martini, L., Bocci, M., Balus, F., Bitar, N., Shah, H., Aissaoui, M., Rusmisel, J., Serbest, Y., Malis, A., Metz, C., McDysan, D., Sugimoto, J., Duckett, M., Loomis, M., Doolan, P., Pan, P., Pate, P., Radoaca, V., Wada, Y., and Y. Seo, "Dynamic Placement of Multi Segment Pseudo Wires", draft-ietf-pwe3-dynamic-ms-pw-13 (work in progress), October 2010. [I-D.ietf-pwe3-redundancy] Muley, P., "Pseudowire (PW) Redundancy", draft-ietf-pwe3-redundancy-03 (work in progress), May 2010. [I-D.ietf-pwe3-segmented-pw] Martini, L., Nadeau, T., Metz, C., Bocci, M., Aissaoui, M., Balus, F., and M. Duckett, "Segmented Pseudowire", draft-ietf-pwe3-segmented-pw-18 (work in progress), September 2010. [I-D.ietf-pwe3-static-pw-status] Martini, L., Swallow, G., Heron, G., and M. Bocci, "Pseudowire Status for Static Pseudowires", draft-ietf-pwe3-static-pw-status-02 (work in progress), March 2011. [RFC3985] Bryant, S. and P. Pate, "Pseudo Wire Emulation Edge-to- Edge (PWE3) Architecture", RFC 3985, March 2005. [RFC4379] Kompella, K. and G. Swallow, "Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures", RFC 4379, February 2006. [RFC5036] Andersson, L., Minei, I., and B. Thomas, "LDP Specification", RFC 5036, October 2007. [RFC5561] Thomas, B., Raza, K., Aggarwal, S., Aggarwal, R., and JL. Le Roux, "LDP Capabilities", RFC 5561, July 2009. Zhang, et al. Expires September 15, 2011 [Page 19] Internet-Draft LDP Extensions for TP PW OAM March 2011 [RFC5586] Bocci, M., Vigoureux, M., and S. Bryant, "MPLS Generic Associated Channel", RFC 5586, June 2009. [RFC5654] Niven-Jenkins, B., Brungard, D., Betts, M., Sprecher, N., and S. Ueno, "Requirements of an MPLS Transport Profile", RFC 5654, September 2009. [RFC5659] Bocci, M. and S. Bryant, "An Architecture for Multi- Segment Pseudowire Emulation Edge-to-Edge", RFC 5659, October 2009. [RFC5860] Vigoureux, M., Ward, D., and M. Betts, "Requirements for Operations, Administration, and Maintenance (OAM) in MPLS Transport Networks", RFC 5860, May 2010. [RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection (BFD)", RFC 5880, June 2010. [RFC5884] Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow, "Bidirectional Forwarding Detection (BFD) for MPLS Label Switched Paths (LSPs)", RFC 5884, June 2010. [RFC5885] Nadeau, T. and C. Pignataro, "Bidirectional Forwarding Detection (BFD) for the Pseudowire Virtual Circuit Connectivity Verification (VCCV)", RFC 5885, June 2010. Authors' Addresses Fei Zhang (editor) ZTE Corporation 4F,RD Building 2,Zijinghua Road Yuhuatai District,Nanjing 210012 P.R.China Phone: +86 025 52877612 Email: zhang.fei3@zte.com.cn Bo Wu (editor) ZTE Corporation 4F,RD Building 2,Zijinghua Road Yuhuatai District,Nanjing 210012 P.R.China Phone: +86 025 52877276 Email: wu.bo@zte.com.cn Zhang, et al. Expires September 15, 2011 [Page 20] Internet-Draft LDP Extensions for TP PW OAM March 2011 Elisa Bellagamba (editor) Ericsson Farogatan 6 Kista, 164 40 Sweden Phone: +46 761440785 Email: elisa.bellagamba@ericsson.com Attila Takacs Ericsson Laborc u. 1. Budapest, 1037 Hungary Email: attila.takacs@ericsson.com Xuehui Dai ZTE Corporation 4F,RD Building 2,Zijinghua Road Yuhuatai District,Nanjing 210012 P.R.China Phone: +86 025 52877612 Email: dai.xuehui@zte.com.cn Min Xiao ZTE Corporation 4F,RD Building 2,Zijinghua Road Yuhuatai District,Nanjing 210012 P.R.China Phone: +86 025 52877612 Email: xiao.min2@zte.com.cn Zhang, et al. 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