CCAMP Working Group                                   E. Bellagamba, Ed.
Internet-Draft                                         L. Andersson, Ed.
Intended status: Standards Track                                Ericsson
Expires: September 2, 6, 2010                            P. Skoldstrom, Ed.
                                                                Acreo AB
                                                                 D. Ward
                                                                 Juniper
                                                           March 1, 5, 2010

            RSVP-TE Extensions for MPLS-TP OAM

  Configuration
              draft-ietf-ccamp-rsvp-te-mpls-tp-oam-ext-00 of pro-active MPLS-TP Operations, Administration, and
         Maintenance (OAM) Functions Using RSVP-TE or LSP Ping
              draft-ietf-ccamp-rsvp-te-mpls-tp-oam-ext-01

Abstract

   This specification is complementary to the GMPLS OAM Configuration
   Framework [OAM-CONF-FWK] and describes technology specific aspects
   for the configuration of pro-active MPLS MPLS-TP
   Operations, Administration Administration, and Maintenance (OAM) functions. Functions for a
   given LSP using a common set of TLVs that is carried on either
   RSVP-TE or LSP Ping.

Status of this Memo

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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1.  Contributing Authors . . . . . . . . . . . . . . . . . . .  3
     1.2.  Requirements Language  . . . . . . . . . . . . . . . . . .  3  4
     1.3.  Overview of BFD OAM operation  . . . . . . . . . . . . . .  4
   2.  Overview of MPLS OAM for Transport Applications  . . . . . . .  4
   3.  RSVP-TE Extensions .  Theory of Operations . . . . . . . . . . . . . . . . . . . . .  5
     3.1.  MPLS OAM Configuration Operation Overview  . . . . . . . .  5
     3.2.  OAM Configuration TLV  . . . . . . . . . . . . . . . . . .  6
     3.3.  BFD Configuration TLV  . . . . . . . . . . . . . . . . . .  8
       3.3.1.  Local Discriminator sub-TLV  . . . . . . . . . . . . . 10
       3.3.2.  Negotiation Timer Parameters . . . . . . . . . . . . . 10
     3.4.  MPLS OAM PM Loss TLV . . . . . . . . . . . . . . . . . . . 11
     3.5.  MPLS OAM PM Delay TLV  . . . . . . . . . . . . . . . . . . 12
     3.6.  MPLS OAM FMS TLV . . . . . . . . . . . . . . . . . . . . . 13
     3.7.  MPLS OAM SOURCE MEP-ID TLV for LSP Ping  . . . . . . . . . 14
   4.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 14 15
   5.  BFD OAM configuration errors . . . . . . . . . . . . . . . . . 15
   6.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 15 16
   7.  Security Considerations  . . . . . . . . . . . . . . . . . . . 15 16
   8.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 15 16
     8.1.  Normative References . . . . . . . . . . . . . . . . . . . 15 16
     8.2.  Informative References . . . . . . . . . . . . . . . . . . 16 17
   Appendix A.  Additional Stuff  . . . . . . . . . . . . . . . . . . 17 18
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 17 18

1.  Introduction

   This document defines the technology specific extensions of RSVP-TE
   for describes the configuration of pro-active MPLS MPLS-TP
   Operations, Administration Administration, and Maintenance (OAM) functions. Functions for a
   given LSP using a common set of TLVs carried on either RSVP-TE
   [RFC3209] or LSP Ping [BFD-Ping].  In particular it specifies
   extensions the
   mechanisms necessary to establish MPLS MPLS-TP OAM entities monitoring a signaled LSP, an
   LSP and defines information elements and procedures to configure pro-
   active MPLS OAM functions.  Initialization and control of on-demand
   MPLS OAM functions are expected to be carried out by directly
   accessing network nodes via a management interface; hence
   configuration and control of on-demand OAM functions are out-of-scope
   of
   for this document.

   Because the Transport Profile of MPLS, by definition [RFC5654], must
   be capable of operating without a control plane, there are two
   options for in-band OAM: by using an NMS or by using LSP-Ping if a
   control plane is not instantiated.

   Pro-active MPLS OAM is based on the Bidirectional Forwarding
   Detection (BFD) protocol [BFD].  Bidirectional Forwarding Detection
   (BFD), as described in [BFD], defines a protocol that provides low-
   overhead, short-duration detection of failures in the path between
   two forwarding engines, including the interfaces, data link(s), and
   to the extent possible the forwarding engines themselves.  BFD can be
   used to track the liveliness and detect data plane failures of
   MPLS-TP point-to-point and might also be extended to p2mp
   connections and detect data plane failures.
   connections.

   MPLS Transport Profile (MPLS-TP) describes a profile of MPLS that
   enables operational models typical in transport networks, while
   providing additional OAM, survivability and other maintenance
   functions not currently supported by MPLS.  [MPLS-TP-OAM-REQ] defines
   the requirements by which for the OAM functionality of MPLS-TP should
   abide. MPLS-TP.

   BFD has been chosen to be the basis of pro-active MPLS-TP OAM
   functions.  MPLS  MPLS-TP OAM extensions for transport applications, which are
   relevant for
   which this document, document specifies the configuration, are specified in
   [BFD-CCCV], [MPLS-PM] [MPLS-PM], and [MPLS-FMS].

1.1.  Contributing Authors

   The editors gratefully acknowledge the contributions of John Drake,
   Attila Takacs and Benoit Tremblay.

1.2.  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 RFC 2119 [RFC2119].

1.3.  Overview of BFD OAM operation

   BFD is a simple hello protocol that in many respects is similar to
   the detection components of well-known routing protocols.  A pair of
   systems transmits BFD packets periodically over each path between the
   two systems, and if a system stops receiving BFD packets for long
   enough, some component in that particular bidirectional path to the
   neighboring system is assumed to have failed.  Systems may also
   negotiate to not send periodic BFD packets in order to reduce
   overhead.

   A path is only declared to be operational when two-way communication
   has been established between systems, though this does not preclude
   the use of unidirectional links to support bidirectional paths (co-
   routed or bidirectional or associated bidirectional).

   Each system estimates how quickly it can send and receive BFD packets
   in order to come to an agreement with its neighbor about how rapidly
   detection of failure will take place.  These estimates can be
   modified in real time in order to adapt to unusual situations.  This
   design also allows for fast systems on a shared medium with a slow
   system to be able to more rapidly detect failures between the fast
   systems while allowing the slow system to participate to the best of
   its ability.

   The ability of each system to control the BFD packet transmission
   rate in both directions provides a mechanism for congestion control,
   particularly when BFD is used across multiple network hops.

   As recommended in [BFD-CCCV], the BFD tool needs to be extended for
   the proactive CV functionality by the addition of an unique
   identifier in order to meet the requirements.  The document in [BFD-
   CCCV] specifies the BFD extension and behavior to meet the
   requirements for MPLS-TP proactive Continuity Check and Connectivity
   Verification functionality and the RDI functionality as defined in
   [MPLS-TP-OAM-REQ].

2.  Overview of MPLS OAM for Transport Applications

   [MPLS-TP-OAM-FWK] describes how MPLS OAM mechanisms are operated to
   meet transport requirements outlined in [MPLS-TP-OAM-REQ].

   [BFD-CCCV] specifies two BFD operation modes: 1) "CC mode", which
   uses periodic BFD message exchanges with symmetric timer settings,
   supporting Continuity Check, 2) "CV/CC mode" which sends unique
   maintenance entity identifiers in the periodic BFD messages
   supporting Connectivity Verification as well as Continuity Check.

   [MPLS-PM] specifies mechanisms for performance monitoring of LSPs, in
   particular it specifies loss and delay measurement OAM functions.

   [MPLS-FMS] specifies fault management signals with which a server LSP
   can notify client LSPs about various fault conditions to suppress
   alarms or to be used as triggers for actions in the client LSPs.  The
   following signals are defined: Alarm Indication Signal (AIS), Link
   Down Indication (LDI) and Locked Report (LKR).  To indicate client
   faults associated with the attachment circuits Client Signal Failure
   Indication (CSF) can be used.  CSF is described in [MPLS-TP-OAM-FWK]. [MPLS-TP-OAM-FWK]
   and in the context of this document is for further study.

   [MPLS-TP-OAM-FWK] describes the mapping of fault conditions to
   consequent actions.  Some of these mappings may be configured by the
   operator, depending on the application of the LSP.  The following
   defects are identified: Loss Of Continuity (LOC), Misconnectivity,
   MEP Misconfiguration and Period Misconfiguration.  Out of these
   defect conditions, the following consequent actions may be
   configurable: 1) whether or not the LOC defect should result in
   blocking the outgoing data traffic; 2) whether or not the "Period
   Misconfiguration defect" should result a signal fail condition.

3.  RSVP-TE Extensions  Theory of Operations

3.1.  MPLS OAM Configuration Operation Overview

   RSVP-TE or LSP Ping can be used to simply establish (i.e., bootstrap)
   a BFD session or it can configure, at different level of details, selectively enable and configure all pro-
   active MPLS OAM functions.  When RSVP-TE is used to configure BFD,  For this specification, BFD MUST be run
   in asynchronous mode and both sides should be in active mode.

   In the simplest scenario RSVP-TE signaling or LSP Ping is used only to
   bootstrap the BFD session.  In this case the initiating node includes
   an 'OAM Configuration TLV' in the Path message it sends to the receiving
   node at the other end of the LSP.  The OAM Type in the "OAM 'OAM
   Configuration TLV" TLV' is set to "MPLS OAM".  Only 'MPLS OAM', the "CC" CC OAM Function flag is set in the "OAM Configuration TLV"
   set, and a "BFD 'BFD Configuration sub-TLV" sub-TLV' is inserted in the "OAM Configuration TLV",
   carrying included.  The sub-TLV
   carries a "Local 'Local Discriminator sub-TLV" sub-TLV' with the discriminator value
   selected locally by the initiating node for the BFD session of associated with
   the signaled LSP.  The N bit flag in the 'BFD Configuration sub-TLV' MUST be set
   to enable timer negotiation/re-negotiation via BFD Control Messages.

   The receiving node MUST use the Local Discriminator value received in the Path message it receives
   to identify the remote end of the BFD session, select a local discriminator value and
   MUST start sending BFD Control Messages after it sent the Resv
   message. session.  The Resv receiving node
   must send a message MUST include the LSP_ATTRIBUTES Object
   reflecting back the contents of to the "OAM initiating node that includes an 'OAM
   Configuration TLV", TLV' containing the same values as it received, except
   that
   for the "Local 'Local Discriminator sub-TLV" MUST carry sub-TLV', which contains the local
   discriminator value used selected by the sender of receiving node for the Resv message. BFD
   session.

   Timer negotiation is
   left to performed in subsequent BFD control messages.
   This operation is similar to LSP Ping based bootstrapping described
   in [BFD-MPLS].

   For detailed MPLS OAM configuration RSVP-TE can be used to configure
   all parameters of pro-active MPLS OAM mechanisms.

   If "CC mode" OAM timer negotiation is to be established, the OAM Type in the "OAM Configuration TLV" is
   set to MPLS OAM, only the "CC" OAM Function flag is set in the "OAM
   Configuration TLV" and the "BFD Configuration TLV" is inserted in done using the
   "OAM Configuration TLV".  The "Local Discriminator sub-TLV" is used
   as described above.  Timer negotiation TLVs defined in this case is done via the
   RSVP-TE control plane, hence
   document rather than with BFD Control Messages, the N bit flag MUST be
   cleared to disable
   timer negotiation/re-negotiation via BFD Control Messages.  The
   "Timer and a 'Timer Negotiation Parameters sub-TLV" sub-TLV' MUST be present
   in the "BFD
   configuration TLV" to specify the acceptable interval for the BFD CC
   messages.

   When timer negotiation is done via the RSVP-TE control plane, 'BFD Configuration sub-TLV'.  In this case, there are two
   configuration options are available: options, symmetric and asymmetric
   configuration. asymmetric.  If symmetric
   configuration is required, used, the S flag in
   "BFD configuration TLV" 'BFD Configuration sub-TLV' MUST
   be set.  If the flag is cleared, the configuration is completed
   asymmetrically in the two directions.  Section 3.3.2 includes a
   detailed explanation of such configuration.

   In the case of the "CV/CC mode" OAM [BFD-CCCV], the "CV" flag MUST be
   set in addition to the CC flag in the "OAM Configuration TLV".  The
   information required to support this functionality is defined in
   [MPLS-TP-IDENTIF] and can be
   [MPLS-TP-IDENTIF].  If RSVP-TE is used, this information is found
   respectively in the SESSION and SENDER_TEMPLATE object with no need
   of further sub-TLV as described in section 3.2.  In case of LSP Ping
   configuration this information is supplied by an additional sub-TLV
   as described in section 3.2.

   Additional OAM functions can be requested by setting the PM/Loss and
   PM/Delay OAM Function flags in the "OAM Configuration TLV".  If these
   flags are set, corresponding sub-TLVs may be included in the "OAM
   Configuration TLV".

   If Fault Management Signals [MPLS-FMS] are required, the Fault
   Management Signals (FMS) OAM Function flag needs to be is set in the
   "OAM 'OAM
   Configuration TLV". TLV'.  If this flag is set, an additional "FMS
   sub-TLV" the corresponding sub-TLV
   may be included in the OAM 'OAM Configuration TLV. TLV'.

3.2.  OAM Configuration TLV

   Below is specified the

   The "OAM Configuration TLV", defined TLV" is depicted in [OAM-CONF-
   FWK]. the following figure.  It
   specifies which the OAM technology/method should functions that are to be used for the LSP.  The subject LSP
   and it is defined in [OAM-CONF-FWK].  For RSVP-TE, the "OAM
   Configuration TLV" is carried in the LSP_ATTRIBUTES object in Path
   and Resv messages.

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |           Type (2) (IANA)     |           Length              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |    OAM Type   |                Reserved                       |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                                                               |
      ~                           sub-TLVs                            ~
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type: indicates the "OAM Configuration TLV" (2) (IANA to assign).

   OAM Type: one octet that specifies the technology specific OAM Type.
   If the requested OAM Type is not supported, an error must be
   generated: "OAM Problem/Unsupported OAM Type".

   This document defines a new OAM Type: "MPLS OAM" (suggested value 2,
   IANA to assign) from the "RSVP-TE OAM Configuration Registry".  The
   "MPLS OAM" type is to be set in the "OAM Configuration TLV" [OAM-
   CONF-FWK] to request the establishment of OAM entities functions
   for MPLS MPLS-TP LSPs.  The specific OAM functions are specified in the
   "Function Flags" sub-TLV as depicted in [OAM-CONF-FWK].

   The receiving LER edge LSR when the MPLS-TP OAM Type is requested should
   check which OAM Function Flags are set in the "Function Flags TLV"
   and look for the corresponding technology specific configuration TLV.

   This document specifies the following

   Additional corresponding sub-TLVs to be carried in the
   "OAM Configuration TLV" for MPLS OAM configuration. are as follows:

      - "BFD Configuration sub-TLV", which MUST be included if the CC
      OAM Function flag is set.  This sub-TLV MUST carry a "BFD Local
      Discriminator sub-TLV" and a "Timer Negotiation Parameters sub-
      TLV" if the N flag is cleared.

      - "MPLS OAM PM Loss sub-TLV", which MAY be included if the PM/Loss
      OAM Function flag is set.  If the "MPLS OAM PM Loss sub-TLV" is
      not included, default configuration values are used.

      - "MPLS OAM PM Delay sub-TLV", which MAY be included if the PM/
      Delay OAM Function flag is set.  If the "MPLS OAM PM Delay sub-
      TLV" is not included, default configuration values are used.

      - "MPLS OAM FMS sub-TLV", which MAY be included if the FMS OAM
      Function flag is set.  If the "MPLS OAM FMS sub-TLV" is not
      included, default configuration values are used.

      - "Unique MEP-ID of Source", which MUST be included in case the
      configuration is done with LSP Ping and CV flag is set.

   Moreover, if the CV flag is set, the CC flag MUST be set at the same
   time.  The format of an MPLS-TP CV/CC message is shown in [BFD-CCCV]
   and it requires, together with the BFD control packet information,
   the "Unique MEP-ID of source of BFD packet".  [MPLS-TP-IDENTIF]
   defines the composition of such identifier as:

   <"Unique MEP-ID of source of BFD packet"> ::=
   <src_node_id><src_tunnel_num><lsp_num>

   GMPLS signaling [RFC 3473] uses a 5-tuple to uniquely identify an LSP
   within an operator's network.  This tuple is composed of a Tunnel
   Endpoint Address, Tunnel_ID, Extended Tunnel ID, and Tunnel Sender
   Address and (GMPLS) LSP_ID.

   Hence, the following mapping is used without the need of redefining a
   new TLV for MPLS-TP proactive CV purpose.

      - Tunnel ID = src_tunnel_num

      - Tunnel Sender Address = src_node_id

      - LSP ID = LSP_Num

   "Tunnel ID" and "Tunnel Sender Address" are included in the "SESSION"
   object [RFC 3209], which is mandatory in both Path and Resv messages.

   "LSP ID" will be the same on both directions and it is included in
   the "SENDER_TEMPLATE" object [RFC 3209] which is mandatory in Path
   messages.

   In case the configuration is done via LSP Ping the "Unique MEP-ID of
   Source" is needed to supply this information.

   [Author's note: the same "Unique MEP-ID of source" will be likely
   required for Performance monitoring purposes.  However for the moment
   in [MPLS-PM] it is stated: "The question of ACH TLV usage and the
   manner of supporting metadata such as authentication keys and node
   identifiers is deliberately omitted.  These issues will be addressed
   in a future version of the document."]

3.3.  BFD Configuration TLV

   The "BFD Configuration TLV" (depicted below) is defined for BFD OAM
   specific configuration parameters.  The "BFD Configuration TLV" is
   carried as a sub-TLV of the "OAM Configuration TLV" in the
   LSP_ATTRIBUTES object both in Path and Resv messages. TLV".

   This new TLV accommodates generic BFD OAM information and carries
   sub-TLVs.

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |           Type (3) (IANA)     |           Length              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |Vers.| PHB |N|S|      Reserved (set to all 0s)                 |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                                                               |
      ~                           sub TLVs                            ~
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type: indicates a new type, the "BFD Configuration TLV" (IANA to
   define).

   Length: indicates the total length including sub-TLVs.

   Version: identifies the BFD protocol version.  If a node does not
   support a specific BFD version an error must be generated: "OAM
   Problem/Unsupported OAM Version &rdquo".

   PHB: Identifies the Per-Hop Behavior (PHB) to be used for periodic
   continuity monitoring messages.

   BFD Negotiation (N): If set timer negotiation/re-negotiation via BFD
   Control Messages is enabled, when cleared it is disabled.

   The "BFD Configuration TLV" MUST include the following sub-TLVs in
   the Path message:

      - "Local Discriminator sub-TLV";

      - "Negotiation Timer Parameters sub-TLV" if N flag is cleared.

   The "BFD Configuration TLV" MUST include the following sub-TLVs in
   the Resv message:

      - "Local Discriminator sub-TLV;"

      - "Negotiation Timer Parameters sub-TLV" if:

         - N flag and S are cleared
         - N flag is cleared and S flag is set and a timing value higher
         than the one received needs to be used

3.3.1.  Local Discriminator sub-TLV

   The "Local Discriminator sub-TLV" is carried as a sub-TLV of the BFD
   Configuration sub-TLV in both Path and Resv messages. sub-TLV.  It is depicted 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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |           Type (1) (IANA)     |         Length = 8            |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                      Local Discriminator                      |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type: indicates a new type, the Local Discriminator sub TLV (1) (IANA
   to define).

   Length: indicates the TLV total length in octets.

   Local Discriminator: A unique, nonzero discriminator value generated
   by the transmitting system and referring to itself, used to
   demultiplex multiple BFD sessions between the same pair of systems.

3.3.2.  Negotiation Timer Parameters

   The "Negotiation Timer Parameters sub-TLV" is depicted 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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |  Req. TX int. Type (2) (IANA) |          Length = 20          |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |         Acceptable Min. Asynchronous TX interval              |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |         Acceptable Min. Asynchronous RX interval              |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |               Required Echo TX Interval                       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |  Detect. Mult.|           Reserved                            |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type: indicates a new type, the "Negotiation Timer Parameters sub-
   TLV" (IANA to define).

   Length: indicates the TLV total length in octets.

   Acceptable Min. Asynchronous TX interval: in case of S (symmetric)
   flag set in the "BFD Configuration" TLV, it expresses the desired
   time interval (in microseconds) at which the LER initiating the
   signaling intends to both transmit and receive BFD periodic control
   packets.  If the receiving LER edge LSR can not support such value, it is
   allowed to reply back with an interval greater than the one proposed.

   In case of S (symmetric) flag cleared in the "BFD Configuration TLV",
   this field expresses the desired time interval (in microseconds) at
   which a LER edge LSR intends to transmit BFD periodic control packets in
   its transmitting direction.

   Acceptable Min. Asynchronous RX interval: in case of S (symmetric)
   flag set in the "BFD Configuration TLV", this field MUST be equal to
   "Acceptable Min. Asynchronous TX interval" and has no additional
   meaning respect to the one described for "Acceptable Min.
   Asynchronous TX interval".

   In case of S (symmetric) flag cleared in the "BFD Configuration TLV",
   it expresses the minimum time interval (in microseconds) at which
   LERs
   edge LSRs can receive BFD periodic control packets.  In case this
   value is greater than the "Acceptable Min. Asynchronous TX interval"
   received from the other LER, edge LSR, such LER edge LSR MUST adopt the
   interval expressed in this "Acceptable Min. Asynchronous RX
   interval".

   Required Echo TX Interval: the minimum interval, in microseconds,
   between received BFD Echo packets that this system is capable of
   supporting, less any jitter applied by the sender as described in
   [BFD] sect. 6.8.9.  This value is also an indication for the
   receiving system of the minimum interval between transmitted BFD Echo
   packets.  If this value is zero, the transmitting system does not
   support the receipt of BFD Echo packets.  If the receiving system can
   not support this value an error MUST be generated "Unsupported BFD TX
   rate interval".

   Detection time multiplier: The negotiated transmit interval,
   multiplied by this value, provides the Detection Time for the
   receiving system in Asynchronous mode.

3.4.  MPLS OAM PM Loss TLV

   The "MPLS OAM PM Loss TLV" depicted below is carried as a sub-TLV of
   the "OAM Configuration 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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |  PM Loss Type (3) (IANA)      |          Length = 16          |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |Vers.|E|C|     |           Reserved                      | PHB |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                    Measurement Interval                       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                      Loss Threshold                           |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type: indicates a new type, the "PM Loss" (IANA to define).

   Length: indicates the TLV total length in octets.

   Version: indicates the Loss measurement protocol version.

   Configuration Flags:

      - E: exclude from the Loss Measurement all G-ACh messages

      - C: require the use of a counter in the "Querier Context" field
      described in [MPLS-PM]

      - Remaining bits: Reserved for future specification and set to 0.

   PHB: identifies the per-hop behavior of packets with loss
   information.

   Measurement Interval: the time interval (in microseconds) at which
   Loss Measurement query messages MUST be sent on both directions.  If
   the LER edge LSR receiving the Path message can not support such value,
   it can reply back with a higher interval.

   Loss Threshold: the threshold value of lost packets over which
   protections MUST be triggered.

3.5.  MPLS OAM PM Delay TLV

   "PM

   The "MPLS OAM PM Delay sub-TLV" is TLV" depicted below. below is carried as a sub-TLV of
   the "OAM Configuration 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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |  PM Delay Type (4) (IANA)     |          Length = 16          |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |Vers.| Flags   |           Reserved                      | PHB |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                    Measurement Interval                       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                      Delay Threshold                          |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type: indicates a new type, the "PM Delay" (IANA to define).

   Length: indicates the TLV total length in octets.

   Version: indicates the Delay measurement protocol version.

   Configuration Flags:

      - E: exclude from the Loss Measurement all G-ACh messages

      - C: require the use of a counter in the "Querier Context" field
      described in [MPLS-PM]

      - Remaining bits: Reserved for future specification and set to 0.

   PHB: - identifies the per-hop behavior of packets with delay
   information.

   Measurement Interval: the time interval (in microseconds) at which
   Delay Measurement query messages MUST be sent on both directions.  If
   the LER edge LSR receiving the Path message can not support such value,
   it can reply back with a higher interval.

   Delay Threshold: the threshold value of lost packets over which
   protections MUST be triggered.

   [Author's note: TBD if we want to include the timestamp format
   negotiation as in [MPLS-PM] 4.2.5.]

3.6.  MPLS OAM FMS TLV

   The "MPLS OAM FMS TLV" depicted below is carried as a sub-TLV of the
   "OAM Configuration 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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |           Type (5)  (IANA)    |        Length (12)            |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |A|D|L|C|                      Reserved       |         |E| PHB |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                      Refresh Timer                            |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type: indicates a new type, the "PM Delay" (IANA to define).

   Length: indicates the TLV total length in octets.

   Signal Flags: are used to enable the following signals:

      - A: Alarm Indication Signal (AIS) as described in [MPLS-FMS]

      - D: Link Down Indication (LDI) as described in [MPLS-FMS]

      - L: Locked Report (LKR) as described in [MPLS-FMS]

      - C: Client Signal Failure (CSF) as described in [MPLS-CSF]

   Configuration Flags:

      - E: used to enable/disable explicitly clearing faults

      - PHB: identifies the per-hop behavior of packets with fault
      management information

   Refresh Timer: indicates the refresh timer (in microseconds) of fault
   indication messages.  If the LER edge LSR receiving the Path message can
   not support such value, it can reply back with a higher interval.

3.7.  MPLS OAM SOURCE MEP-ID TLV for LSP Ping

   The "MPLS OAM SOURCE MEP-ID TLV for LSP Ping" depicted below is
   carried as a sub-TLV of the "OAM Configuration TLV" in case LSP Ping
   is used.

        0                   1                   2                   3
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |           Type (6)  (IANA)    |        Length = 12            |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                         SRC NODE ID                           |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |           TUNNEL ID           |           LSP ID              |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type: indicates a new type, the "MPLS OAM SOURCE MEP-ID" (IANA to
   define).

   Length: indicates the TLV total length in octets.

   SRC NODE ID: 32-bit node identifier as defined in [MPLS-TP-IDENTIF].

   TUNNEL ID: a 16-bit unsigned integer unique to the node as defined in
   [MPLS-TP-IDENTIF].

   LSP ID: a 16-bit unsigned integer unique within the Tunnel_ID as
   defined in [MPLS-TP-IDENTIF].

4.  IANA Considerations

   This document specifies the following new TLV types:

      - "BFD Configuration" type: 2;

      - "MPLS OAM PM Loss" type: 3;

      - "MPLS OAM PM Delay" type: 4;

      - "MPLS OAM PM FMS" type: 5.

   sub-TLV types to be carried in the "BFD Configuration sub-TLV":

      - "Local Discriminator" sub-TLV type: 1;

      - "Negotiation Timer Parameters" sub-TLV type: 2.

5.  BFD OAM configuration errors

   In addition to error values specified in [OAM-CONF-FWK] and [ETH-OAM]
   this document defines the following values for the "OAM Problem"
   Error Code:

      - "MPLS OAM Unsupported Functionality";

      - "OAM Problem/Unsupported TX rate interval".

6.  Acknowledgements

   The authors would like to thank David Allan, Lou Berger, Annamaria
   Fulignoli, Eric Gray, Andras Kern, David Jocha and David Sinicrope
   for their useful comments.

7.  Security Considerations

   The signaling of OAM related parameters and the automatic
   establishment of OAM entities introduces additional security
   considerations to those discussed in [RFC3473].  In particular, a
   network element could be overloaded, if an attacker would request
   liveliness monitoring, with frequent periodic messages, for a high
   number of LSPs, targeting a single network element.

   Security aspects will be covered in more detailed in subsequent
   versions of this document.

8.  References

8.1.  Normative References

   [BFD]      Katz, D. and D. Ward, "Bidirectional Forwarding
              Detection", 2009, <draft-ietf-bfd-base>.

   [MPLS-CSF]
              He, J. and H. Li, "Indication of Client Failure in
              MPLS-TP", 2009, <draft-he-mpls-tp-csf>.

   [MPLS-FMS]
              Swallow, G., Fulignoli, A., and M. Vigoureux, "MPLS Fault
              Management OAM", 2009, <draft-sfv-mpls-tp-fault>.

   [MPLS-PM]  Bryant, S. and D. Frost, "Packet Loss and Delay
              Measurement for the  MPLS Transport Profile", 2009,
              <draft-frost-mpls-tp-loss-delay>.

   [MPLS-TP-IDENTIF]
              Bocci, M. and G. Swallow, "MPLS-TP Identifiers", 2009,
              <draft-swallow-mpls-tp-identifiers>.

   [MPLS-TP-OAM-REQ]
              Vigoureux, M., Ward, D., and M. Betts, "Requirements for
              OAM in MPLS Transport Networks", 2009,
              <draft-ietf-mpls-tp-oam-requirements>.

   [OAM-CONF-FWK]
              Takacs, A., Fedyk, D., and J. van He, "OAM Configuration
              Framework for GMPLS RSVP-TE", 2009,
              <draft-ietf-ccamp-oam-configuration-fwk>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC3471]  Berger, L., "Generalized Multi-Protocol Label Switching
              (GMPLS) Signaling Functional Description", RFC 3471,
              January 2003.

   [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.

8.2.  Informative References

   [BFD-CCCV]
              Fulignoli, A., Boutros, S., and M. Vigoreux, "MPLS-TP BFD
              for Proactive CC-CV and RDI", 2009,
              <draft-asm-mpls-tp-bfd-cc-cv>.

   [BFD-Ping]
              Bahadur, N., Aggarwal, R., Ward, D., Nadeau, T., Sprecher,
              N., and Y. Weingarten, "LSP-Ping and BFD encapsulation
              over ACH", 2009,
              <draft-nitinb-mpls-tp-lsp-ping-bfd-procedures-02>.

   [ETH-OAM]  Takacs, A., Gero, B., Fedyk, D., Mohan, D., and D. Long,
              "GMPLS RSVP-TE Extensions for Ethernet OAM", 2009,
              <draft-ietf-ccamp-rsvp-te-eth-oam-ext>.

   [LSP Ping]
              Kompella, K. and G. Swallow, "Detecting Multi-Protocol
              Label Switched (MPLS) Data Plane Failures", 2006, <RFC
              3479>.

   [MPLS-TP OAM Analysis]
              Sprecher, N., Nadeau, T., van Helvoort, H., and
              Weingarten, "MPLS-TP OAM Analysis", 2006,
              <draft-sprecher-mpls-tp-oam-analysis>.

   [MPLS-TP-FWK]
              Bocci, M., Bryant, S., Frost, D., and L. Levrau, "OAM
              Configuration Framework for GMPLS RSVP-TE", 2009,
              <draft-ietf-mpls-tp-framework>.

   [MPLS-TP-OAM-FWK]
              Busi, I. and B. Niven-Jenkins, "MPLS-TP OAM Framework and
              Overview", 2009, <draft-ietf-mpls-tp-oam-framework>.

   [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.

Appendix A.  Additional Stuff

   This becomes an Appendix.

Authors' Addresses

   Elisa Bellagamba (editor)
   Ericsson
   Farogatan 6
   Kista,   164 40
   Sweden

   Phone: +46 761440785
   Email: elisa.bellagamba@ericsson.com

   Loa Andersson (editor)
   Ericsson
   Farogatan 6
   Kista,   164 40
   Sweden

   Phone:
   Email: loa.andersson@ericsson.com
   Pontus Skoldstrom (editor)
   Acreo AB
   Electrum 236
   Kista,   164 40
   Sweden

   Phone: +46 8 6327731
   Email: pontus.skoldstrom@acreo.se

   Dave Ward
   Juniper

   Phone:
   Email: dward@juniper.net