One document matched: draft-ietf-mpls-tp-cc-cv-rdi-02.txt

Differences from draft-ietf-mpls-tp-cc-cv-rdi-01.txt


MPLS Working Group                                       Dave Allan, Ed. 
Internet Draft                                                 Ericsson 
Intended status: Standards Track                                        
Expires: April 2011                                   George Swallow Ed. 
                                                      Cisco Systems, Inc 
 
                                                          John Drake Ed. 
                                                                 Juniper 
 
                                                        October 22, 2010 
                                    

     Proactive Connectivity Verification, Continuity Check and Remote 
               Defect indication for MPLS Transport Profile 
                      draft-ietf-mpls-tp-cc-cv-rdi-02 


Abstract 

   Continuity Check (CC), Proactive Connectivity Verification (CV) and 
   Remote Defect Indication (RDI) functionalities are required for MPLS-
   TP OAM.  
    
   Continuity Check monitors the integrity of the continuity of the LSP 
   for any loss of continuity defect. Connectivity verification monitors 
   the integrity of the routing of the LSP between sink and source for 
   any connectivity issues. RDI enables an End Point to report, to its 
   associated End Point, a fault or defect condition that it detects on 
   a PW, LSP or Section. 
    
   This document specifies methods for proactive CV, CC, and RDI for 
   MPLS-TP Label Switched Path (LSP), PWs and Sections using 
   Bidirectional Forwarding Detection (BFD). 
 

Requirements Language 

   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 [1]. 

Status of this Memo 

   This Internet-Draft is submitted to IETF in full conformance 
   with the provisions of BCP 78 and BCP 79. 

   Internet-Drafts are working documents of the Internet 
   Engineering Task Force (IETF), its areas, and its working 

 
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   groups.  Note that other groups may also distribute working 
   documents as Internet-Drafts. 

   Internet-Drafts are draft documents valid for a maximum of six 
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   This Internet-Draft will expire on November 28, 2010. 

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   Copyright (c) 2010 IETF Trust and the persons identified as the 
   document authors.  All rights reserved. 

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Table of Contents 

   1. Introduction...................................................3 
   1.1. Authors......................................................4 
   2. Conventions used in this document..............................4 
   2.1. Terminology..................................................4 
   2.2. Issues for discussion........................................5 
   3. MPLS CC, proactive CV and RDI Mechanism using BFD..............5 
   3.1. ACH code points for CC and proactive CV......................6 
   3.2. MPLS BFD CC Message format...................................6 
   3.3. MPLS BFD proactive CV Message format.........................7 
   3.4. BFD Session in MPLS-TP terminology...........................7 
   3.5. BFD Profile for MPLS-TP......................................8 
   3.5.1. Session initiation.........................................9 
   3.5.2. Defect entry criteria......................................9 
 
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   3.5.3. Defect entry consequent action............................10 
   3.5.4. Defect exit criteria......................................11 
   3.5.5. State machines............................................11 
   3.5.6. Configuration of MPLS-TP BFD sessions.....................14 
   3.5.7. Discriminator values......................................14 
   4. Acknowledgments...............................................15 
   5. IANA Considerations...........................................15 
   6. Security Considerations.......................................15 
   7. References....................................................15 
   7.1. Normative References........................................15 
   7.2. Informative References......................................16 
    

1. Introduction 

   In traditional transport networks, circuits are provisioned on two or 
   more switches. Service Providers (SP) need OAM tools to detect mis-
   connectivity and loss of continuity of transport circuits. Both PWs 
   and MPLS-TP LSPs [7] emulating traditional transport circuits need to 
   provide the same CC and proactive CV capabilities as required in 
   draft-ietf-mpls-tp-oam-requirements[3]. This document describes the 
   use of BFD for CC, proactive CV, and RDI of a PW, LSP or SPME between 
   two Maintenance Entity Group End Points (MEPs). 

   As described in [9], Continuity Check (CC) and Proactive Connectivity 
   Verification (CV) functions are used to detect loss of continuity 
   (LOC), and unintended connectivity between two MEPs (e.g. mismerging 
   or misconnectivity or unexpected MEP).  

   The Remote Defect Indication (RDI) is an indicator that is 
   transmitted by a MEP to communicate to its peer MEP that a signal 
   fail condition exists. RDI is only used for bidirectional LSPs and is 
   associated with proactive CC & CV packet generation. 

   This document specifies the BFD extension and behavior to satisfy the 
   CC, proactive CV monitoring and the RDI functional requirements for 
   both co-routed and associated bi-directional LSPs. Supported 
   encapsulations include GAL/G-ACh, VCCV and UDP/IP. Procedures for 
   uni-directional LSPs are for further study. 

   The mechanisms specified in this document are restricted to BFD 
   asynchronous mode. 

    



 
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1.1. Authors 

David Allan, John Drake, George Swallow, Annamaria Fulignoli, Sami 
Boutros, Siva Sivabalan, David Ward, Martin Vigoureux. 

2. Conventions used in this document 

2.1. Terminology 

ACH: Associated Channel Header 

BFD: Bidirectional Forwarding Detection 

CV: Connectivity Verification 

GAL: Generalized Alert Label 

LDI: Link Down Indication 

LKI: Lock Instruct 

LKR: Lock Report 

LSR: Label Switching Router 

MEG: Maintenance Entity Group 

MEP: Maintenance Entity Group End Point 

MIP: Maintenance Entity Group Intermediate Point 

MPLS-OAM: MPLS Operations, Administration and Maintenance 

MPLS-TP: MPLS Transport Profile 

MPLS-TP LSP: Uni-directional or Bidirectional Label Switch Path 
representing a circuit 

MS-PW: Multi-Segment PseudoWire 

NMS: Network Management System 

PW: Pseudo Wire  

RDI: Remote Defect Indication.  

SPME: Sub-Path Maintenance Entity 

 
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TTL: Time To Live 

TLV: Type Length Value 

VCCV: Virtual Circuit Connectivity Verification 

2.2. Issues for discussion 

   1) Requirement for additional BFD diagnostic codes? 

              1. When periodicity of CV cannot be supported 

3. MPLS CC, proactive CV and RDI Mechanism using BFD 

   This document proposes distinct encapsulations and code points for 
   ACh encapsulated BFD depending on whether the mode of operation is CC 
   or CV:  

  o  CC mode: defines a new code point in the Associated Channel Header 
     (ACH) described in [2].In this mode Continuity Check and RDI 
     functionalities are supported.  

  o  CV mode: defines a new code point in the Associated Channel Header 
     (ACH) described in [2]. The ACH with "MPLS Proactive CV" code 
     point indicates that the message is an MPLS BFD proactive CV and 
     CC message and CC, CV and RDI functionalities are supported. 

   RDI: is communicated via the BFD diagnostic field in BFD CC and CV 
   messages. It is not a distinct PDU. A sink MEP will encode a 
   diagnostic code of "1- Control detection time expired" when the 
   interval times detect multipler have been exceeded, and with "3 - 
   neighbor signaled session down" as a consequence of the sink MEP 
   receiving AIS with LDI set. A sink MEP that has started sending diag 
   code 3 will NOT change it to 1 when the detection timer expires. 

   In accordance with RFC 5586, when these packets are encapsulated in 
   an IP header the fields in the IP header are set as defined in RFC 
   5884. It should also be noted that existing ACh code points and 
   mechanisms for negotiating the control channel and connectivity 
   verification (i.e. OAM functions) between PEs are specified for 
   VCCV[6]. 

    





 
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3.1. ACH code points for CC and proactive CV 

    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 0 1|Version|     Flags     |0xHH   BFD CC/CV Code Point    | 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
    
       Figure 1: ACH Indication of MPLS-TP Connectivity Verification 
    

   The first nibble (0001b) indicates the ACH. 

   The version and the flags are set to 0 as specified in [2]. 

   The code point is either 

   - BFD CC code point = 0xHH. [HH to be assigned by IANA from the PW 
   Associated Channel Type registry.] or, 

   - BFD proactive CV code point = 0xHH. [HH to be assigned by IANA from 
   the PW Associated Channel Type registry.] 

   Both CC and CV modes apply to PWs, MPLS LSPs (including tandem 
   connection monitoring), and Sections. 

   CC and CV operation can be simultaneously employed on an ME within a 
   single BFD session. The expected usage is that normal operation is to 
   send CC BFD PDUs with every nth BFD PDU augmented with a source MEP 
   ID and identified as requiring additional processing by the different 
   ACh channel type. 

3.2. MPLS BFD CC Message format 

   The format of an MPLS CC Message is shown below. 

    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 0 1|Version|     Flags     |    0xHH BFD CC Code point     | 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   |                                                               | 
   ~                  BFD Control Packet                           ~ 
   |                                                               | 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
                     Figure 2: MPLS CC Message 
    

 
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3.3. MPLS BFD proactive CV Message format 

   The format of an MPLS CV Message is shown below. 

    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 0 1|Version|     Flags     |    0xHH  BFD CV Code Point    | 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   |                                                               | 
   ~                  BFD Control Packet                           ~ 
   |                                                               | 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   |                                                               | 
   ~          Unique MEP-ID of source of the BFD packet            ~ 
   |                                                               | 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
    
                     Figure 3: MPLS CV Message 
    

   As shown in Figure 3, BFD Control packet as defined in [4] is 
   transmitted as MPLS labeled packets along with the ACH. Appended to 
   the BFD control packet is a MEP Source ID TLV. The length in the BFD 
   control packet is as per [4]. There are 4 possible Source MEP TLVs 
   (corresponding to the MEP IDs defined in [8] [type fields to be 
   assigned by IANA]. The type fields are: 

      X1 - ICC encoded MEP ID 

      X2 - LSP-MEP_ID 

      X3 - PW MEP ID 

      X4 - PW Segment endpoint ID 

   When GAL label is used, the TTL field of the GAL MUST be set to at 
   least 1, and the GAL will be the end of stack label (S=1). 

3.4. BFD Session in MPLS-TP terminology 

   A BFD session corresponds to a CC or a proactive CV OAM instance in 
   MPLS-TP terminology. 

   A BFD session is enabled when the CC or proactive CV functionality is 
   enabled on a configured Maintenance Entity (ME)..  


 
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   On a Sink MEP, a BFD session can be in DOWN, INIT or UP state as 
   detailed in [4]. 

   When on a ME the CC or proactive CV functionality is disabled, the 
   BFD session transitions to the ADMIN DOWN State and the BFD session 
   ends. 

   A new BFD session is initiated when the operator enables or re-
   enables the CC or CV functionality on the same ME. 

3.5. BFD Profile for MPLS-TP 

   BFD MUST operate in asynchronous mode. In this mode, the BFD Control 
   packets are periodically sent at configurable time rate. This rate is 
   typically a fixed value for the lifetime of the session. In the rare 
   circumstance where an operator has a reason to change session 
   parameters, the session must be moved to the ADMIN DOWN state. 
   Poll/final discipline can only used for VCCV and UDP/IP encapsulated 
   BFD. 

   The transport profile is designed to operate independent of the 
   control plane; hence the C bit SHOULD be set. 

   This document specifies bi-directional BFD for p2p transport LSPs, 
   hence the M bit MUST be clear. 

   There are two modes of operation for bi-directional LSPs. One in 
   which the session state of both directions of the LSP is coordinated 
   and one constructed from BFD sessions in such a way that the two 
   directions operate independently. A single bi-directional BFD session 
   is used for coordinated operation. Two independent BFD sessions are 
   used for independent operation.  

   Coordinated operation is as described in [4]. Independent operation 
   requires clarification of two aspects of [4]. Independent operation 
   is characterized by the setting of MinRxInterval to zero by the MEP 
   that is typically the session originator (referred to as the source 
   MEP), and there will be a session originator at either end of the bi-
   directional LSP. Each source MEP will have a corresponding sink MEP 
   that has been configured to a Tx interval of zero.  

   The base spec is unclear on aspects of how a MEP with a BFD transmit 
   rate set to zero behaves. One interpretation is that no periodic 
   messages on the reverse component of the bi-directional LSP originate 
   with that MEP, it will only originate messages on a state change.  

   The first clarification is that when a state change occurs a MEP set 
   to a transmit rate of zero sends BFD control messages with a one 
 
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   second period on the reverse component until such time that the state 
   change is confirmed by the session peer. At this point the MEP set to 
   a transmit rate of zero can resume quiescent behavior. This adds 
   robustness to all state transitions in the RxInterval=0 case. 

   The second is that the originating MEP (the one with a non-zero 
   TxInterval) will ignore a DOWN state received from a zero interval 
   peer. This means that the zero interval peer will continue to send 
   DOWN state messages that include the RDI diagnostic code as the state 
   change is never confirmed. This adds robustness to the exchange of 
   RDI indication on a uni-directional failure (for both session types 
   DOWN with a diagnostic of either control detection period expired or 
   neighbor signaled session down offering RDI functionality).  

   A further extension to the base specification is that there are 
   additional OAM protocol exchanges that act as inputs to the BFD state 
   machine; these are the Link Down Indication [5] and the Lock 
   Instruct/Lock Report transactions; Lock Report interaction being 
   optional. 

3.5.1. Session initiation 

   In all scenarios a BFD session starts with both ends in the DOWN 
   state. DOWN state messages exchanged include the desired Tx and Rx 
   rates for the session. If a node cannot support the Min Tx rate 
   desired by a peer MEP it does not transition from down to the INIT 
   state and sends a diagnostic code (TBD) indicating that the requested 
   Tx rate cannot be supported.  

   Otherwise once a transition from DOWN to INIT has occurred, the 
   session progresses as per [4]. In both the DOWN and INIT states 
   messages are transmitted at a rate of one per second and the defect 
   detection interval is fixed at 3.5 seconds. On transition to the UP 
   state message periodicity changes to the negotiated rate and the 
   detect interval switches to detect multiplier times the session 
   peer's Tx Rate.   

3.5.2. Defect entry criteria 

   There are further defect criteria beyond those that are defined in 
   [4] to consider given the possibility of mis-connectivity and mis-
   configuration defects. The result is the criteria for a LSP direction 
   to transition from the defect free state to a defect state is a 
   superset of that in the BFD base specification [4]. 
   The following conditions cause a MEP to enter the defect state for CC 
   or CV: 
     1. BFD session times out (Loss of Continuity defect). 
 
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     2. Receipt of a link down indication. 
     3. Receipt of an unexpected M bit (Session Mis-configuration 
        defect). 
 
   And the following will cause the MEP to enter the defect state for CV 
   operation 
     1. BFD control packets are received with an unexpected 
        encapsulation (mis-connectivity defect), these include: 
          - a PW receiving a packet with a GAL 
          - an LSP receiving an IP header instead of a GAL 
          (note there are other possibilities that can also alias as an 
          OAM packet) 
     2. Receipt of an unexpected globally unique Source MEP identifier 
        (Mis-connectivity defect). 
     3. Receipt of an unexpected session discriminator in the your 
        discriminator field (mis-connectivity defect). 
     4. Receipt of an expected session discriminator with an unexpected 
        label (mis-connectivity defect). 
      
   The effective defect hierarchy (order of checking) is 

     1. Receiving nothing. 

     2. Receiving link down indication. 

     3. Receiving from an incorrect source (determined by whatever 
        means). 

     4. Receiving from a correct source (as near as can be determined), 
        but with incorrect session information). 

     5. Receiving control packets in all discernable ways correct. 

3.5.3. Defect entry consequent action 

   Upon defect entry a sink MEP will assert signal fail into any client 
   (sub-)layers. It will also communicate session DOWN to its session 
   peer. 

   The blocking of traffic as consequent action MUST be driven only by a 
   defect's consequent action as specified in draft-ietf-mpls-tp-oam-
   framework [9] section 5.1.1.2. 
 
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   When the defect is mis-branching, the LSP termination will silently 
   discard all non-oam traffic received. 

3.5.4. Defect exit criteria 

3.5.4.1. Exit from a Loss of continuity defect 

   For a coordinated session, exit from a loss of connectivity defect is 
   as described in figure 4 which updates [4]. 

   For an independent session, exit from a loss of connectivity defect 
   occurs upon receipt of a well formed control packet from the peer MEP 
   as described in figures 5 and 6. 

3.5.4.2. Exit from a session mis-configuration defect 

   [editors: for a future version of the document] 

3.5.4.3. Exit from a mis-connectivity defect 

   [Editors node: The shift to CC with interleaved CV suggests the CV 
   periodicity may not be known by a sink MEP, hence exit criteria from 
   a mis-connectivity defect may not be able to be established. We 
   suggest two possible resolutions for this: 

      1. Exit criteria is manual intervention. 

      2. A minimum CV insertion rate (say 1/sec) be specified such that 
         the exit criteria be specified as no mis-connected CV PDUs be 
         received for a minimum of 3 times the minimum insertion rate] 

3.5.5. State machines 

   The following state machines update [4]. They have been modified to 
   include AIS with LDI set and LKI as inputs to the state machine and 
   to clarify the behavior for independent mode. LKR is an optional 
   input. 

   The coordinated session state machine has been augmented to indicate 
   AIS with LDI set and optionally LKR as inputs to the state machine. 
   For a session that is in the UP state, receipt of AIS with LDI set or 
   optionally LKR will transition the session into the DOWN state. 

  




 
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                             +--+ 
                             |  | UP, ADMIN DOWN, TIMER, AIS-LDI, LKR 
                             |  V 
               DOWN        +------+  INIT 
              +------------|      |------------+ 
              |            | DOWN |            | 
              |  +-------->|      |<--------+  | 
              |  |         +------+         |  | 
              |  |                          |  | 
              |  |               ADMIN DOWN,|  | 
              |  |ADMIN DOWN,          DOWN,|  | 
              |  |TIMER               TIMER,|  | 
              V  |AIS-LDI,LKR   AIS-LDI,LKR |  V 
            +------+                      +------+ 
       +----|      |                      |      |----+ 
   DOWN|    | INIT |--------------------->|  UP  |    |INIT, UP 
       +--->|      | INIT, UP             |      |<---+ 
            +------+                      +------+ 
 
       Figure 4: State machine for coordinated session operation 
    

   For independent mode, there are two state machines. One for the 
   source MEP (who requested MinRxInterval=0) and the sink MEP (who 
   agreed to MinRxInterval=0). 

   The source MEP will not transition out of the UP state once 
   initialized except in the case of a forced ADMIN DOWN. Hence AIS-with 
   LDI set and optionally LKR do not enter into the state machine 
   transition from the UP state, but do enter into the INIT and DOWN 
   states. 












 
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                             +--+ 
                             |  | UP, ADMIN DOWN, TIMER 
                             |  V 
               DOWN        +------+  INIT 
              +------------|      |------------+ 
              |            | DOWN |            | 
              |  +-------->|      |<--------+  | 
              |  |         +------+         |  | 
              |  |                          |  | 
              |  |ADMIN DOWN     ADMIN DOWN |  | 
              |  |TIMER,                    |  | 
              |  |AIS-LDI,                  |  | 
              V  |LKR                       |  V 
            +------+                      +------+ 
       +----|      |                      |      |----+ 
   DOWN|    | INIT |--------------------->|  UP  |    | INIT, UP, DOWN,  
       +--->|      | INIT, UP             |      |<---+ AIS-LDI, LKR 
            +------+                      +------+ 
 
     Figure 5: State machine for source MEP for independent session 
                               operation 
                             
   The sink MEP state machine (for which the transmit interval has been 
   set to zero) is modified to: 
    
   1) Permit direct transition from DOWN to UP once the session has been 
   initialized. With the exception of via the ADMIN DOWN state, the 
   source MEP will never transition from the UP state, hence in normal 
   unidirectional fault scenarios will never transition to the INIT 
   state. 










 
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                             +--+ 
                             |  | ADMIN DOWN, TIMER, AIS-LDI, LKR 
                             |  V 
               DOWN        +------+  INIT, UP 
              +------------|      |------------+ 
              |            | DOWN |            | 
              |  +-------->|      |<--------+  | 
              |  |         +------+         |  | 
              |  |                          |  | 
              |  |               ADMIN DOWN,|  | 
              |  |ADMIN DOWN,    TIMER,     |  | 
              |  |TIMER,         DOWN,      |  | 
              |  |AIS-LDI,       AIS-LDI,   |  V 
             V  |LKR            LKR        |  | 
            +------+                      +------+ 
       +----|      |                      |      |----+ 
   DOWN|    | INIT |--------------------->|  UP  |    |INIT, UP 
       +--->|      | INIT, UP             |      |<---+ 
            +------+                      +------+ 
 
     Figure 6: State machine for the sink MEP for independent session 
                                 operation 

3.5.6. Configuration of MPLS-TP BFD sessions 

   [Editors note, for a future revision of the document] 

3.5.7. Discriminator values 

   In the BFD control packet the discriminator values have either local 
   to the sink MEP or no significance (when not known). 

   My Discriminator field MUST be set to a nonzero value (it can be a 
   fixed value), the transmitted your discriminator value MUST reflect 
   back the received value of My discriminator field or be set to 0 if 
   that value is not known. 

   Although the BFD base specification permits an implementation to 
   change the my discriminator field at arbitrary times, this is not 
   permitted for CV mode in order to avoid race conditions in mis-
   connectivity defects. 


 
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4. Acknowledgments 

   To be added in a later version of this document 

5. IANA Considerations 

   To be added in a later version of this document 

6. Security Considerations 

   The security considerations for the authentication TLV need further 
   study. 

   Base BFD foresees an optional authentication section (see [4] 
   section 6.7); that can be extended also to the tool proposed in 
   this document. 

   Authentication methods that require checksum calculation on the 
   outgoing packet must extend the checksum also on the ME 
   Identifier Section. This is possible but seems uncorrelated with 
   the solution proposed in this document: it could be better to 
   use the simple password authentication method. 

    

7. References 

7.1. Normative References  

  [1]   Bradner, S., "Key words for use in RFCs to Indicate 
        Requirement Levels", BCP 14, RFC 2119, March 1997. 

  [2]   Bocci, M. et al., " MPLS Generic Associated Channel ", RFC 
        5586 , June 2009 

  [3]   Vigoureux, M., Betts, M. and D. Ward, "Requirements for 
        Operations Administration and Maintenance in MPLS 
        Transport Networks", RFC5860, May 2010 

  [4]   Katz, D. and D. Ward, "Bidirectional Forwarding 
        Detection", RFC 5880, June 2010 

  [5]   Swallow, G. et al., "MPLS Fault Management OAM", draft-
        ietf-mpls-tp-fault-02 (work in progress), July 2010 

  [6]   Nadeau, T. and C. Pignataro, "Pseudowire Virtual Circuit 
        Connectivity Verification (VCCV): A Control Channel for 
        Pseudowires", RFC 5085, December 2007 
 
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7.2. Informative References 

  [7]   Bocci, M., et al., "A Framework for MPLS in Transport 
        Networks", RFC5921, July 2010 

  [8]   Bocci, M. and G. Swallow, "MPLS-TP Identifiers", draft-
        swallow-mpls-tp-identifiers-02 (work in progress), July 
        2010 

  [9]   Allan, D., and Busi, I. "MPLS-TP OAM Framework", draft-
        ietf-mpls-tp-oam-framework-09 (work in progress), October 
        2010 

   


































 
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   Authors' Addresses 

   Dave Allan 
   Ericsson 
   Email: david.i.allan@ericsson.com  
    
   John Drake 
   Juniper 
   Email: jdrake@juniper.net 
    
   George Swallow 
   Cisco Systems, Inc. 
   Email: swallow@cisco.com 
    
   Annamaria Fulignoli  
   Ericsson 
   Email: annamaria.fulignoli@ericsson.com 
    
   Sami Boutros  
   Cisco Systems, Inc. 
   Email: sboutros@cisco.com 
    
   Martin Vigoureux  
   Alcatel-Lucent 
   Email: martin.vigoureux@alcatel-lucent.com 
    
   Siva Sivabalan 
   Cisco Systems, Inc. 
   Email: msiva@cisco.com 
    
   David Ward 
   Juniper 
   Email: dward@juniper.net 
    














 
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