MPLS Working Group                                         E. Bellagamba, Ed. Bellagamba
Internet-Draft                                                 G. Mirsky, Ed. Mirsky
Intended status: Standards Track                                Ericsson
Expires: April 3, July 15, 2015                                      L. Andersson
                                                     Huawei Technologies
                                                           P. Skoldstrom, Ed. Skoldstrom
                                                                Acreo AB
                                                                 D. Ward
                                                                   Cisco
                                                                J. Drake
                                                                 Juniper
                                                      September 30, 2014
                                                        January 11, 2015

Configuration of Pro-Active Operations, Administration, and Maintenance
    (OAM) Functions for MPLS-based Transport Networks using LSP Ping
              draft-ietf-mpls-lsp-ping-mpls-tp-oam-conf-07
              draft-ietf-mpls-lsp-ping-mpls-tp-oam-conf-08

Abstract

   This specification describes the configuration of pro-active MPLS-TP
   Operations, Administration, and Maintenance (OAM) Functions for a
   given LSP using a set of TLVs that are carried by the LSP-Ping
   protocol.

Status of This Memo

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   provisions of BCP 78 and BCP 79.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Conventions used in this document . . . . . . . . . . . .   4
       1.1.1.  Terminology . . . . . . . . . . . . . . . . . . . . .   4
       1.1.2.  Requirements Language . . . . . . . . . . . . . . . .   4
   2.  Theory of Operations  . . . . . . . . . . . . . . . . . . . .   4
     2.1.  MPLS OAM Configuration Operation Overview . . . . . . . .   4
       2.1.1.  Configuration of BFD sessions . . . . . . . . . . . .   5
       2.1.2.  Configuration of Performance Monitoring . . . . . . .   6
       2.1.3.  Configuration of Fault Management Signals . . . . . .   6
     2.2.  MPLS OAM Functions TLV  . . . . . . . . . . . . . . . . .   6
       2.2.1.  BFD Configuration sub-TLV . . . . . . . . . . . . . .   8
       2.2.2.  Local Discriminator sub-TLV . . . . . . . . . . . . .  10
       2.2.3.  Negotiation Timer Parameters sub-TLV  . . . . . . . .  10
       2.2.4.  BFD Authentication sub-TLV  . . . . . . . . . . . . .  12
       2.2.5.  Performance Measurement  Traffic Class sub-TLV . . . . . . . . . . . . . . . .  12
       2.2.6.  Performance Measurement sub-TLV . . . . . . . . . . .  13
       2.2.7.  PM Loss Measurement sub-TLV . . . . . . . . . . . . .  14
       2.2.7.  15
       2.2.8.  PM Delay Measurement sub-TLV  . . . . . . . . . . . .  15
       2.2.8.  16
       2.2.9.  Fault Managemet Management Signal sub-TLV . . . . . . . . . . .  16
       2.2.9.  17
       2.2.10. Source MEP-ID sub-TLV . . . . . . . . . . . . . . . .  17  18
   3.  Summary of MPLS OAM configuration errors  . . . . . . . . . .  19
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  18
     3.1.  20
     4.1.  TLV and sub-TLV Allocation  . . . . . . . . . . . . . . .  18
     3.2.  20
     4.2.  OAM configuration errors  . . . . . . . . . . . . . . . .  18
   4.  21
   5.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  22
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  19
   5.  22
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  19
     5.1.  23
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  19
     5.2.  23
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  20  24
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  21  24

1.  Introduction

   This document describes the configuration of pro-active MPLS-TP
   Operations, Administration, and Maintenance (OAM) Functions for a
   given LSP using TLVs carried in LSP-Ping [RFC4379].  In particular it
   specifies the mechanisms necessary to establish MPLS-TP OAM entities
   at the maintenance points for monitoring and performing measurements
   on an LSP, as well as defining information elements and procedures to
   configure pro-active MPLS-TP OAM functions running between LERs.
   Initialization and control of on-demand MPLS-TP 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 for this document.

   The Transport Profile of MPLS must, by definition [RFC5654], be
   capable of operating without a control plane.  Therefore there are
   several options for configuring MPLS-TP OAM, without a control plane
   by either using an NMS or LSP Ping, or with a control plane using
   signaling protocols RSVP-TE [RFC3209] and/or T-LDP [RFC5036].

   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.  [RFC5860] defines the
   requirements for the OAM functionality of MPLS-TP.

   Pro-active MPLS-TP OAM is performed by set of protocols, Bi-
   directional Forwarding Detection (BFD) [RFC6428] for Continuity
   Check/Connectivity Verification, the delay measurement protocol (DM)
   [RFC6374], [RFC6375] for delay and delay variation (jitter)
   measurements, and the loss measurement (LM) protocol [RFC6374],
   [RFC6375] for packet loss and throughput measurements.  Additionally
   there is a number of Fault Management Signals that can be configured.

   BFD is a protocol that provides low-overhead, fast 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 detect the continuity and
   mis-connection defects of MPLS-TP point-to-point and might also be
   extended to support point-to-multipoint label switched paths (LSPs).

   The delay and loss measurements protocols [RFC6374], [RFC6375] use a
   simple query/response model for performing both uni- and bi-
   directional measurements that allow the originating node to measure
   packet loss and delay in forward or forward and reverse directions.
   By timestamping and/or writing current packet counters to the
   measurement packets at four times (Tx and Rx in both directions)
   current delays and packet losses can be calculated.  By performing
   successive delay measurements the delay and/or inter-packet delay
   variation (jitter) can be calculated.  Current throughput can be
   calculated from the packet loss measurements by dividing the number
   of packets sent/received with the time it took to perform the
   measurement, given by the timestamp in LM header.  Combined with a
   packet generator the throughput measurement can be used to measure
   the maximum capacity of a particular LSP.  It should be noted that
   here we are not configuring on-demand throughput estimates based on
   saturating the connection as defined in [RFC6371].  Rather, we only
   enable the estimation of the current throughput based on loss
   measurements.

1.1.  Conventions used in this document

1.1.1.  Terminology

   BFD - Bidirectional Forwarding Detection

   DM - Delay Measurement

   FMS - Fault Management Signal

   G-ACh - Generic Associated Channel

   LSP - Label Switched Path

   LM - Loss Measurement

   MEP - Maintanence Maintenance Entity Group End Point

   MPLS - Multi-Protocol Label Switching

   MPLS-TP - MPLS Transport Profile

   PM - Performance Measurement

   TC - Traffic Class

1.1.2.  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].

2.  Theory of Operations

2.1.  MPLS OAM Configuration Operation Overview

   The MPLS-TP OAM tool set is described in the [RFC6669].

   LSP Ping, or alternatively RSVP-TE [RSVP-TE-CONF], can be used to
   simply enable the different OAM functions, by setting the
   corresponding flags in the MPLS OAM Functions TLV, Section 2.2.  For
   a more detailed configuration one may include sub-TLVs for the
   different OAM functions in order to specify various parameters in
   detail.

   Typically intermediate nodes should not process or modify any of the simply forward OAM configuration TLVs but simply forward them to
   the end-node.
   There is end-node without any processing or modification At least one
   exception to this and that is if the FMS sub-TLV, sub-TLV Section 2.2.8, 2.2.9 is present.
   This sub-TLV has to be examined even by intermediate nodes.  The sub-TLV sub-
   TLV MAY be present if a flag is set in the MPLS OAM Functions TLV.

2.1.1.  Configuration of BFD sessions

   For this specification, BFD MUST be run in either one of the two modes:

      - Asynchronous mode, where both sides should be in active mode

      - Unidirectional mode

   In the simplest scenario LSP Ping [RFC5884], or alternatively RSVP-TE
   [RSVP-TE CONF],
   [RSVP-TE-CONF], is used only to bootstrap a BFD session for an LSP,
   without any timer negotiation.

   Timer negotiation can be performed either in subsequent BFD control
   messages (in this case the operation is similar to LSP Ping based
   bootstrapping described in [RFC5884]) or directly in the LSP-Ping
   configuration messages.

   When BFD Control packets are transported in the ACH encapsulation
   they are not protected by any end-to-end checksum, only lower-layers
   are providing error detection/correction.  A single bit error, e.g. a
   flipped bit in the BFD State field could cause the receiving end to
   wrongly conclude that the link is down and in turn trigger protection
   switching.  To prevent this from happening the BFD Configuration sub-
   TLV, Section 2.2.1, has an Integrity flag that when set enables BFD
   Authentication using Keyed SHA1 with an empty key (all 0s) [RFC5880].
   This would make every BFD Control packet carry an SHA1 hash of itself
   that can be used to detect errors.

   If BFD Authentication using a pre-shared key/password is desired
   (i.e. authentication and not only error detection) the BFD
   Authentication sub-TLV, Section 2.2.4, MUST be included in the BFD
   Configuration sub-TLV.  The BFD Authentication sub-TLV is used to
   specify which authentication method that should be used and which
   pre-shared key/ password that should be used for this particular
   session.  How the key exchange is performed is out of scope of this
   document.

2.1.2.  Configuration of Performance Monitoring

   It is possible to configure Performance Monitoring functionalities
   such as Loss, Delay, Delay/Interpacket Delay variation (jitter), and
   Throughput as described in [RFC6374].

   When configuring Performance monitoring functionalities it is
   possible to choose either the default configuration, by only setting
   the respective flags in the MPLS OAM functions TLV, or a customized
   configuration.  To customize the configuration one would set the
   respective flags in the including the respective Loss and/or Delay
   sub-TLVs).

   By setting the PM Loss flag in the MPLS OAM Functions TLV and
   including the PM Loss sub-TLV, Section 2.2.6, 2.2.7, one can configure the
   measurement interval and loss threshold values for triggering
   protection.

   Delay measurements are configured by setting PM Delay flag in the
   MPLS OAM Functions TLV and including the PM Delay sub-TLV,
   Section 2.2.7, 2.2.8, one can configure the measurement interval and the
   delay threshold values for triggering protection.

2.1.3.  Configuration of Fault Management Signals

   To configure Fault Management Signals (FMS) and their refresh time
   the FMS flag in the MPLS OAM Functions TLV MUST be set and the FMS
   sub-TLV MUST be included.  When configuring FMS, an implementation
   can enable the default configuration by setting the FMS flag in the
   OAM Function Flags sub-TLV.  If an implementation wishes  In order to modify the default
   configuration it includes a the MPLS OAM FMS sub-TLV. sub-TLV MUST be included.

   If an intermediate point is meant to originate fault management
   signal messages this means that such an intermediate point is
   associated to with a Server MEP through a co-located MPLS-TP client/server client/
   server adaptation function.  Such a function and the Fault Management subscription flag
   in the MPLS OAM FMS sub-TLV been set as indication of the request to
   create the association at each intermediate node of the client LSP.
   Corresponding Server MEP needs to be configured by its own LSP-ping
   session or, alternatively, via an NMS or RSVP-TE.
   However, by setting the S flag Section 2.2.8 in the FMS sub-TLV a
   client LSP can indicate that it would like an association to be
   created to the server MEP(s) on any intermediate nodes.

2.2.  MPLS OAM Functions TLV

   The MPLS OAM Functions TLV presented in Figure 1 is carried as a TLV
   of the LSP MPLS Echo request/response Request/Reply messages [RFC4379].

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  MPLS OAM Func. Type (TBD1) (TBA1)   |           Length              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |C|V|L|D|F|                Must be zero
   |C|V|F|L|D|T|             Reserved  (MBZ)                       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   ~                           sub-TLVs                            ~
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                  Figure 1: MPLS OAM Functions TLV format

   The MPLS OAM Functions TLV contains a number of flags indicating
   which OAM functions should be activated as well as OAM function
   specific sub-TLVs with configuration parameters for the particular
   function.

   Type: indicates the MPLS OAM Functions TLV Section 3. 4.

   Length: the length of the MPLS OAM Function Flags field including the
   total length of the sub-TLVs in octets.

   MPLS OAM Function Flags: a bitmap numbered from left to right as
   shown in the figure.

   These flags are defined in this document as presented in Table 1:

   +------------+--------------------+---------------------------------+
   |    Bit     | MPLS OAM Function  | Description                     |
   |  Position  |        Flag        |                                 |
   +------------+--------------------+---------------------------------+
   |     0      |         C          | Continuity Check (CC)           |
   |     1      |         V          | Connectivity Verification (CV)  |
   |     2      |         F          | Fault Management Signal (FMS)   |
   |     3      |         L          | Performance Measurement/Loss    |
   |            |                    | (PM/Loss)                       |
   |     4      |         D          | Performance Measurement/Delay   |
   |            |                    | (PM/Delay)                      |
   |     5      |         T          | Throughput Measurement)         |
   |    6-31    |                    | Reserved                        |
   +------------+--------------------+---------------------------------+

                        Table 1: MPLS OAM TLV Flags

   Sub-TLVs corresponding to the different flags are as follows:

      - BFD Configuration sub-TLV, which MUST be included if the CC and/
      or the CV 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.  The "Source MEP-ID
      sub-TLV" MUST also be included.  If the I flag is set, the "BFD
      Authentication sub-TLV" may MAY be included.

      - PM Loss sub-TLV within the "Performance Monitoring sub-TLV",
      which MAY be included if the PM/Loss OAM Function flag is set.  If
      the "PM Loss sub-TLV" is not included, default configuration
      values are used.  Such sub-TLV MAY also be included in case the
      Throughput function flag is set and there is the need to specify
      measurement interval different from the default ones.  In fact the
      throughput measurement make use of the same tool as the loss
      measurement, hence the same TLV is used.

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

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

2.2.1.  BFD Configuration sub-TLV

   The BFD Configuration sub-TLV, depicted Figure 2, is defined for BFD
   OAM specific configuration parameters.  The "BFD Configuration sub-
   TLV" is carried as a sub-TLV of the "OAM Functions TLV".

   This 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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | BFD Conf. sub-Type    (100)   |           Length              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Vers.| PHB |N|S|I|G|U|B|
   |Vers.|N|S|I|G|U|B|         Reserved (set to all 0s)            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   ~                           sub-TLVs                            ~
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                Figure 2: BFD Configuration sub-TLV format

   Sub-type: indicates a new sub-type, the BFD Configuration sub-TLV
   (IANA to define, suggested value
   (value 100).

   Length: indicates the length of the TLV including sub-TLVs but
   excluding the Type and Length field, Value field in octets. octets (4).

   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".

   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.

   Symmetric session (S): If set the BFD session MUST use symmetric
   timing values.

   Integrity (I): If set BFD Authentication MUST be enabled.  If the BFD
   Configuration sub-TLV does not include a BFD Authentication sub-TLV
   the authentication MUST use Keyed SHA1 with an empty pre-shared key
   (all 0s).

   Encapsulation Capability (G): if  If the egress LSR does not support BFD Authentication an
   error MUST be generated: "OAM Problem/BFD Authentication
   unsupported".

   Encapsulation Capability (G): if set, it shows the capability of
   encapsulating BFD messages into G-ACh channel.  If both the G bit and
   U bit are set, configuration gives precedence to the G bit.

   Encapsulation Capability (U): if set, it shows the capability of
   encapsulating BFD messages into IP/UDP packets.  If both the G bit
   and U bit are set, configuration gives precedence to the G bit.

   If the egress LSR does not support any of the ingress LSR
   Encapsulation Capabilities an error MUST be generated: "OAM Problem/
   Unsupported BFD Encapsulation format".

   Bidirectional (B): if set, it configures BFD in the Bidirectional
   mode.  If it is not set it configures BFD in unidirectional mode.  In
   the second case, the source node does not expect any Discriminator
   values back from the destination node.

   Reserved: Reserved for future specification and set to 0 on
   transmission and ignored when received.

   The BFD Configuration sub-TLV MUST include the following sub-TLVs in
   the LSP MPLS Echo request Request message:

      - Local Discriminator sub-TLV; sub-TLV, if B flag is set in the MPLS Echo
      Request;
      - Negotiation Timer Parameters sub-TLV if the N flag is cleared.

   The BFD Configuration sub-TLV MUST include the following sub-TLVs in
   the LSP MPLS Echo reply Reply message:

      - Local Discriminator sub-TLV;

      - Negotiation Timer Parameters sub-TLV if:

         - the N and S flags are cleared, or if:

         - the N flag is cleared and the S flag is set, and the
         Negotiation Timer Parameters sub-TLV received by the egress
         contains unsupported values.  In this case an updated
         Negotiation Timer Parameters sub-TLV, containing values
         supported by the egress node, is returned to the ingress.

2.2.2.  Local Discriminator sub-TLV

   The Local Discriminator sub-TLV is carried as a sub-TLV of the "BFD
   Configuration sub-TLV" and is depicted in Figure 3.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Lcl. Discr. sub-Type (101)   |            Length             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                       Local Discriminator                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

               Figure 3: Local Discriminator sub-TLV format

   Type: indicates a new type, the "Local Discriminator sub-TLV" (IANA
   to define, suggested value (value
   101).

   Length: indicates the sub-TLV length in octets, excluding of the sub-
   type and Length field. Value field in octets . (4)

   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.

2.2.3.  Negotiation Timer Parameters sub-TLV

   The Negotiation Timer Parameters sub-TLV is carried as a sub-TLV of
   the BFD Configuration sub-TLV and is depicted in Figure 4.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Nego. Timer sub-type (102)    |             Length            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         Acceptable Min. Asynchronous TX interval              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         Acceptable Min. Asynchronous RX interval              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |               Required Echo TX Interval                       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

           Figure 4: Negotiation Timer Parameters sub-TLV format

   Sub-type: indicates a new sub-type, the Negotiation Timer Parameters
   sub-TLV (IANA to define, suggested value (value 102).

   Length: indicates the length of the parameters Value field in octets (12).

   Acceptable Min. Asynchronous TX interval: in case of S (symmetric)
   flag set in the BFD Configuration sub-TLV, defined in Section 2.2.1,
   it expresses the desired time interval (in microseconds) at which the
   ingress LER intends to both transmit and receive BFD periodic control
   packets.  If the receiving edge LSR can not cannot support such value, it
   SHOULD reply with an interval greater than the one proposed.

   In case of S (symmetric) flag cleared in the BFD Configuration sub-
   TLV, this field expresses the desired time interval (in microseconds)
   at which a 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 sub-TLV, Figure 2, 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 sub-
   TLV, it expresses the minimum time interval (in microseconds) at
   which edge LSRs can receive BFD periodic control packets.  In case
   this value is greater than the value of Acceptable Min. Asynchronous
   TX interval received from the other edge LSR, such 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

   [RFC5880] 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
   cannot support this value the "Unsupported BFD TX Echo rate interval"
   error MUST be generated.  By default the value is set to 0.

2.2.4.  BFD Authentication sub-TLV

   The "BFD Authentication sub-TLV" is carried as a sub-TLV of the "BFD
   Configuration sub-TLV" and is depicted in Figure 5.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    BFD Auth. sub-type (103)   |             Length            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Auth Type   |  Auth Key ID  |         Reserved (0s)         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                Figure 5: BFD Authentication sub-TLV format

   Sub-type: indicates a new type, the BFD Authentication sub-TLV (IANA
   to define, suggested value (value
   103).

   Length: indicates the TLV total length in octets, exluding of the Type
   and Length fields. (4) Value field in octets (4).

   Auth Type: indicates which type of authentication to use.  The same
   values as are defined in section 4.1 of [RFC5880] are used.

   Auth Key ID: indicates which authentication key or password
   (depending on Auth Type) should be used.  How the key exchange is
   performed is out of scope of this document.  If the egress LSR does
   not support this Auth Key ID an "OAM Problem/Mismatch of BFD
   Authentication Key ID" error MUST be generated.

   Reserved: Reserved for future specification and set to 0 on
   transmission and ignored when received.

2.2.5.  Performance Measurement sub-TLV

   If the MPLS OAM Functions TLV has either the L (Loss), D (Delay) or T
   (Throughput) flag set, the Performance Measurement  Traffic Class sub-TLV MUST be
   present.

   The Performance Measurement Traffic Class sub-TLV provides the configuration
   information mentioned in Section 7 of [RFC6374].  It includes support
   for the configuration of quality thresholds and, is carried as described in
   [RFC6374], "the crossing a sub-TLV of which will trigger warnings or alarms,
   and result reporting and exception notification will be integrated
   into the system-wide network management "BFD
   Configuration sub-TLV" or "Fault Management Signal sub-TLV"
   Section 2.2.9 and reporting framework."

   In case the values need to be different than the default ones the
   Performance Measurement sub-TLV MAY include the following sub-TLVs:

      - PM Loss sub-TLV if the L flag is set in the MPLS OAM Functions
      TLV;

      - PM Delay sub-TLV if the D flag is set in the MPLS OAM Functions
      TLV.

   The Performance Measurement sub-TLV depicted depicted in Figure 6 is carried
   as a sub-TLV of the MPLS OAM Functions TLV. 6.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Perf Monitoring Type (200) Traffic Class sub-Type (104)  |            Length             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |D|L|J|Y|K|C|
   |  TC |                 Reserved (set to all 0s)                |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                  Figure 6: Performance Measurement Traffic Class sub-TLV format

   Sub-type:

   Type: indicates a new sub-type, type, the Performance Management sub-
   TLV" (IANA to define, suggested value 200). "Traffic Class sub-TLV" (value 104).

   Length: indicates the TLV length of the Value field in octets, exluding octets . (4)

   TC: Identifies the Type and
   Length fields.

   Configuration Flags, Traffic Class (TC) [RFC5462] for periodic
   continuity monitoring messages or packets with fault management
   information.

   If TC sub-TLV is present, then the specific function description please
   refer to [RFC6374]:

      - D: Delay inferred/direct (0=INFERRED, 1=DIRECT)

      - L: Loss inferred/direct (0=INFERRED, 1=DIRECT)

      - J: Delay variation/jitter (1=ACTIVE, 0=NOT ACTIVE)

      - Y: Dyadic (1=ACTIVE, 0=NOT ACTIVE)

      - K: Loopback (1=ACTIVE, 0=NOT ACTIVE)

      - C: Combined (1=ACTIVE, 0=NOT ACTIVE)

   Reserved: Reserved for future specification and set to 0 on
   transmission and ignored when received. value of the TC field MUST be used
   as the value of the TC field of an MPLS label stack entry.  If the TC
   sub-TLV is absent from "BFD Configuration sub-TLV" or "Fault
   Management Signal sub-TLV", then selection of the TC value is local
   decision.

2.2.6.  PM Loss  Performance Measurement sub-TLV

   If the MPLS OAM Functions TLV has either the L (Loss), D (Delay) or T
   (Throughput) flag set, the Performance Measurement sub-TLV MUST be
   present.  Failure to include the correct sub-TLVs MUST result in an
   "OAM Problem/ Configuration Error" error being generated.

   The PM Loss Performance Measurement sub-TLV depicted provides the configuration
   information mentioned in Figure Section 7 is carried of [RFC6374].  It includes support
   for the configuration of quality thresholds and, as a
   sub-TLV described in
   [RFC6374], "the crossing of which will trigger warnings or alarms,
   and result reporting and exception notification will be integrated
   into the Performance Measurement sub-TLV.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 system-wide network management and reporting framework."

   In case the values need to be different than the default ones the
   Performance Measurement sub-TLV MAY include the following sub-TLVs:

      - PM Loss sub-TLV if the L flag is set in the MPLS OAM Functions
      TLV;

      - PM Delay sub-TLV if the D flag is set in the MPLS OAM Functions
      TLV.

   The Performance Measurement sub-TLV depicted in Figure 7 is carried
   as a sub-TLV of the MPLS OAM Functions 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 sub-type (201) Perf Monitoring Type (200)    |          Length               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | OTF |T|B|
   |D|L|J|Y|K|C|            Reserved (set to all 0s)               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                    Measurement Interval                       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                       Test Interval                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                      Loss Threshold                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

             Figure 7: PM Loss Performance Measurement sub-TLV format

   Sub-type: indicates a new sub-type, the PM Loss Measurement sub-TLV
   (IANA to define, suggested value 201). Performance Management sub-
   TLV" (value 200).

   Length: indicates the length of the parameters in octets (16).

   OTF: Origin Timestamp Format of the Origin Timestamp Value field described in [RFC6374].  By default it is set to IEEE 1588 version 1. octets (4).

   Configuration Flags, for the specific function description please
   refer to [RFC6374] for further details: [RFC6374]:

      - T: Traffic-class-specific measurement indicator.  Set to 1 when
      the measurement operation is scoped to packets of a particular
      traffic class (DSCP value), and 0 otherwise.  When set to 1, the
      DS field of the message indicates D: Delay inferred/direct (0=INFERRED, 1=DIRECT).  If the measured traffic class.  By
      default it is set to 1. egress
      LSR does not support specified mode an "OAM Problem/Unsupported
      Delay Mode" error MUST be generated.

      - B: Octet (byte) count.  When set to 1, indicates that L: Loss inferred/direct (0=INFERRED, 1=DIRECT).  If the
      Counter 1-4 fields represent octet counts.  When set to 0,
      indicates that egress
      LSR does not support specified mode an "OAM Problem/Unsupported
      Loss Mode" error MUST be generated.

      - J: Delay variation/jitter (1=ACTIVE, 0=NOT ACTIVE).  If the Counter 1-4 fields represent packet counts.  By
      default it
      egress LSR does not support Delay variation measurements and the J
      flag is set to 0. set, an "OAM Problem/Delay variation unsupported" error
      MUST be generated.

      - Y: Dyadic (1=ACTIVE, 0=NOT ACTIVE).  If the egress LSR does not
      support Dyadic mode and the Y flag is set, an "OAM Problem/Dyadic
      mode unsupported" error MUST be generated.

      - K: Loopback (1=ACTIVE, 0=NOT ACTIVE).  If the egress LSR does
      not support Loopback mode and the K flag is set, an "OAM Problem/
      Loopback mode unsupported" error MUST be generated.

      - C: Combined (1=ACTIVE, 0=NOT ACTIVE).  If the egress LSR does
      not support Combined mode and the C flag is set, an "OAM Problem/
      Combined mode unsupported" error MUST be generated.

   Reserved: Reserved for future specification and set to 0 on
   transmission and ignored when received.

   Measurement Interval: the time interval (in milliseconds) at which
   Loss Measurement query messages MUST be sent on both directions.  If
   the edge LSR receiving the Path message can not support such value,
   it SHOULD reply with a higher interval.  By default it is set to
   (100) as per [RFC6375].

   Test Interval: test messages interval in milliseconds as described in
   [RFC6374].  By default it is set to (10) as per [RFC6375].

   Loss Threshold: the threshold value of measured lost packets per
   measurement over which action(s) SHOULD be triggered.

2.2.7.  PM Delay Loss Measurement sub-TLV

   The PM Delay Loss Measurement sub-TLV" sub-TLV depicted in Figure 8 is carried as a
   sub-TLV of the Performance Monitoring Measurement sub-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 (202) Loss sub-type (201)       |          Length               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | OTF |T|B|              Reserved (set to all 0s)               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                    Measurement Interval                       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                       Test Interval                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                      Delay                      Loss Threshold                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

               Figure 8: PM Delay Loss Measurement sub-TLV format

   Sub-type: indicates a new sub-type, the PM Delay Loss Measurement sub-TLV"
   (IANA to define, suggested value 202). sub-TLV
   (value 201).

   Length: indicates the length of the parameters Value field in octets (16).

   OTF: Origin Timestamp Format of the Origin Timestamp field described
   in [RFC6374].  By default it is set to IEEE 1588 version 1.  If the
   egress LSR cannot support this value an "OAM Problem/Unsupported
   Timestamp Format" error MUST be generated.

   Configuration Flags, please refer to [RFC6374] for further details:

      - T: Traffic-class-specific measurement indicator.  Set to 1 when
      the measurement operation is scoped to packets of a particular
      traffic class (DSCP value), and 0 otherwise.  When set to 1, the
      DS field of the message indicates the measured traffic class.  By
      default it is set to 1.

      - B: Octet (byte) count.  When set to 1, indicates that the
      Counter 1-4 fields represent octet counts.  When set to 0,
      indicates that the Counter 1-4 fields represent packet counts.  By
      default it is set to 0.

   Reserved: Reserved for future specification and set to 0 on
   transmission and ignored when received.

   Measurement Interval: the time interval (in milliseconds) at which
   Delay
   Loss Measurement query messages MUST be sent on both directions.  If
   the edge LSR receiving the Path message can not cannot support such value, it can
   SHOULD reply with a higher interval.  By default it is set to (1000) (100)
   as per [RFC6375].

   Test Interval: test messages interval (in milliseconds) in milliseconds as described in
   [RFC6374].  By default it is set to (10) as per [RFC6375].

   Delay

   Loss Threshold: the threshold value of measured two-way delay (in
   milliseconds) lost packets per
   measurement over which action(s) SHOULD be triggered.

2.2.8.  Fault Managemet Signal  PM Delay Measurement sub-TLV

   The FMS sub-TLV PM Delay Measurement sub-TLV" depicted in Figure 9 is carried as
   a sub-TLV of the
   MPLS OAM Configuration Performance Monitoring sub-TLV.  When both working and protection
   paths are configured, both LSPs SHOULD be configured with identical
   settings of the E flag, T flag, and the refresh timer.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       FMS sub-type (300)  PM Delay Type (202)          |          Length               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |E|S|T|
   | OTF |T|B|             Reserved (set to all 0s)|      Refresh Timer 0s)                |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                    Measurement Interval                       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                       Test Interval                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | PHB                      Delay Threshold                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

               Figure 9: Fault Management Signal PM Delay Measurement sub-TLV format

   Sub-type: indicates a new sub-type, the FMS sub-TLV (IANA to define,
   suggested value 300). PM Delay Measurement sub-TLV"
   (value 202).

   Length: indicates the length of the parameters Value field in octets (4).

   FMS Signal Flags are used to enable the FMS signals at end point MEPs
   and the Server MEPs (16).

   OTF: Origin Timestamp Format of the links over which the LSP is forwarded.  In
   this document only the S flag pertains to Server MEPs.

   The following flags are defined:

      - E: Enable Alarm Indication Signal (AIS) and Lock Report (LKR)
      signalling as Origin Timestamp field described
   in [RFC6427].  Default value [RFC6374].  By default it is 1
      (enabled).

      - S: Indicate set to a server MEP that its should transmit AIS and LKR
      signals on IEEE 1588 version 1.  If the client LSP.  Default
   egress LSR cannot support this value is 0 (disabled). an "OAM Problem/Unsupported
   Timestamp Format" error MUST be generated.

   Configuration Flags, please refer to [RFC6374] for further details:

      - T: Traffic-class-specific measurement indicator.  Set timer value, enabled to 1 when
      the configuration of a specific
      timer value.  Default value measurement operation is scoped to packets of a particular
      traffic class (DSCP value), and 0 (disabled). otherwise.  When set to 1, the
      DS field of the message indicates the measured traffic class.  By
      default it is set to 1.

      - Remaining bits: B: Octet (byte) count.  When set to 1, indicates that the
      Counter 1-4 fields represent octet counts.  When set to 0,
      indicates that the Counter 1-4 fields represent packet counts.  By
      default it is set to 0.

   Reserved: Reserved for future specification and set to 0.

   Refresh Timer: indicates 0 on
   transmission and ignored when received.

   Measurement Interval: the refresh timer of fault indication
   messages, in seconds.  The value time interval (in milliseconds) at which
   Delay Measurement query messages MUST be between 1 to 20 seconds as
   specified for the Refresh Timer field in [RFC6427]. sent on both directions.  If
   the edge LSR receiving the Path message can not cannot support the value such value, it SHOULD
   can reply with a higher timer value.

   PHB: identifies interval.  By default it is set to (1000) as
   per [RFC6375].

   Test Interval: test messages interval (in milliseconds) as described
   in [RFC6374].  By default it is set to (10) as per [RFC6375].

   Delay Threshold: the per-hop behavior threshold value of packets with fault management
   information. measured two-way delay (in
   milliseconds) over which action(s) SHOULD be triggered.

2.2.9.  Source MEP-ID  Fault Management Signal sub-TLV

   The Source MEP-ID FMS sub-TLV depicted in Figure 10 is carried as a sub-
   TLV sub-TLV of the
   MPLS OAM Functions TLV.

   Note that support Configuration sub-TLV.  When both working and protection
   paths are configured, both LSPs SHOULD be configured with identical
   settings of ITU IDs is out-of-scope. the E flag, T flag, and the refresh timer.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Source MEP-ID       FMS sub-type (400) (300)      |            Length             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |E|S|T|            Reserved           |                       Source Node ID      Refresh Timer      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |           Tunnel ID                                                               |           LSP ID
   ~                           sub-TLVs                            ~
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

             Figure 10: Source MEP-ID Fault Management Signal sub-TLV format

   Sub-type: indicates a new sub-type, the Source MEP-ID FMS sub-TLV (IANA
   to define, suggested value 400). (value 300).

   Length: indicates the length of the TLV Value field in octets, excluding octets (4).

   FMS Signal Flags are used to enable the Type FMS signals at end point MEPs
   and Length fields. (8)

   Source Node ID: 32-bit node identifier the Server MEPs of the links over which the LSP is forwarded.  In
   this document only the S flag pertains to Server MEPs.

   The following flags are defined:

      - E: Enable Alarm Indication Signal (AIS) and Lock Report (LKR)
      signaling as defined described in [RFC6370].

   Tunnel ID: [RFC6427].  Default value is 1
      (enabled).  If the egress MEP does not support FMS signal
      generation an "OAM Problem/Fault management signaling unsupported"
      error MUST be generated.

      - S: Indicate to a 16-bit unsigned integer unique server MEP that it should transmit AIS and LKR
      signals on the client LSP.  Default value is 0 (disabled).  If a
      Server MEP which is capable of generating FMS messages is for some
      reason unable to do so for the LSP being signaled an "OAM Problem/
      Unable to create fault management association" error MUST be
      generated.

      - T: Set timer value, enabled the configuration of a specific
      timer value.  Default value is 0 (disabled).

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

   Refresh Timer: indicates the refresh timer of fault indication
   messages, in seconds.  The value MUST be between 1 to 20 seconds as
   specified for the Refresh Timer field in [RFC6427].  If the edge LSR
   receiving the Path message cannot support the value it SHOULD reply
   with a higher timer value.

   FMS sub-TLV MAY include Traffic Class sub-TLV Section 2.2.5.  If TC
   sub-TLV is present, the value of the TC field MUST be used as the
   value of the TC field of an MPLS label stack entry for FMS messages.
   If the TC sub-TLV is absent, then selection of the TC value is local
   decision.

2.2.10.  Source MEP-ID sub-TLV

   The Source MEP-ID sub-TLV depicted in Figure 11 is carried as a sub-
   TLV of the MPLS OAM Functions TLV.

   Note that support of ITU IDs is out-of-scope.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Source MEP-ID sub-type (400)  |           Length              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                       Source Node ID                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |           Tunnel ID           |           LSP ID              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                  Figure 11: Source MEP-ID sub-TLV format

   Sub-type: indicates a new sub-type, the Source MEP-ID sub-TLV (value
   400).

   Length: indicates the length of the Value field in octets (8).

   Source Node ID: 32-bit node identifier as defined in [RFC6370].

   Tunnel ID: a 16-bit unsigned integer unique to the node as defined in
   [RFC6370].

   LSP ID: a 16-bit unsigned integer unique within the Tunnel_ID as
   defined in [RFC6370].

3.  Summary of MPLS OAM configuration errors

   This is the summary of Return Codes [RFC4379] defined in this
   document:

      - If an egress LSR does not support the specified BFD version, an
      error MUST be generated: "OAM Problem/Unsupported BFD Version".

      - If an egress LSR does not support the specified BFD
      Encapsulation format, an error MUST be generated: "OAM Problem/
      Unsupported BFD Encapsulation format".

      - If an egress LSR does not support BFD Authentication, and it is
      requested, an error MUST be generated: "OAM Problem/BFD
      Authentication unsupported".

      - If an egress LSR does not support the specified BFD
      Authentication Type, an error MUST be generated: "OAM Problem/
      Unsupported BFD Authentication Type".

      - If an egress LSR is not able to use the specified Authentication
      Key ID, an error MUST be generated: "OAM Problem/Mismatch of BFD
      Authentication Key ID".

      - If an egress LSR does not support the specified Timestamp
      Format, an error MUST be generated: "OAM Problem/Unsupported
      Timestamp Format".

      - If an egress LSR does not support specified Delay mode, an "OAM
      Problem/Unsupported Delay Mode" error MUST be generated.

      - If an egress LSR does not support specified Loss mode, an "OAM
      Problem/Unsupported Loss Mode" error MUST be generated.

      - If an egress LSR does not support Delay variation measurements,
      and it is requested, an "OAM Problem/Delay variation unsupported"
      error MUST be generated.

      - If an egress LSR does not support Dyadic mode, and it is
      requested, an "OAM Problem/Dyadic mode unsupported" error MUST be
      generated.

      - If an egress LSR does not support Loopback mode, and it is
      requested, an "OAM Problem/Loopback mode unsupported" error MUST
      be generated.

      - If an egress LSR does not support Combined mode, and it is
      requested, an "OAM Problem/Combined mode unsupported" error MUST
      be generated.

      - If an egress LSR does not support Fault Monitoring Signals, and
      it is requested, an "OAM Problem/Fault management signaling
      unsupported" error MUST be generated.

      - If an intermediate server MEP supports Fault Monitoring Signals
      but is unable to the node as defined in
   [RFC6370].

   LSP ID: a 16-bit unsigned integer unique within the Tunnel_ID as
   defined in [RFC6370].

3. create an association, when requested to do so,
      an "OAM Problem/Unable to create fault management association"
      error MUST be generated.

4.  IANA Considerations

3.1.

4.1.  TLV and sub-TLV Allocation

   Note: The

   IANA considerations in this document is written according
   to the allocation policies specified in RFC4379.  However there is a
   draft that suggest changes to these allocation policies, draft-pac-
   mpls-lsp-ping-tlvs-and-sub-tlvs-registry if the working group accept maintains the new allocation specied in that draft the allocations made this
   draft, this IANA Considerations section in this document will be re-
   written.

   IANA maintians a registry Multi-Protocol Label Switching (MPLS) Label
   Switched Paths (LSPs) Ping Parameters registry, and within that
   registry a sub-registry for TLVs and sub-TLVs.

   IANA is requested a new TLV from the standards action range (0-16383)
   and sub-TLVs as follows from this sub-registry.

   +------+----------+---------------------------------+---------------+
   | Type | Sub-type | Value Field                     | Reference     |
   +------+----------+---------------------------------+---------------+
   | TBD1 TBA1 |          | MPLS OAM Functions              | This document |
   |      | 100      | BFD Configuration               | This document |
   |      | 101      | BFD Local Discriminator         | This document |
   |      | 102      | BFD Negotiation Timer           | This document |
   |      |          | Parameters                      |               |
   |      | 103      | BFD Authentication              | This document |
   |      | 104      | Traffic Class                   | This document |
   |      | 200      | Performance Measurement         | This document |
   |      | 201      | PM Loss Measurement             | This document |
   |      | 202      | PM Delay Measurement            | This document |
   |      | 203      | Fault Management Signal         | This document |
   |      | 204      | Source MEP-ID                   | This document |
   +------+----------+---------------------------------+---------------+

                     Table 2: IANA TLV Type Allocation

3.2.

4.2.  OAM configuration errors

   IANA maintians maintains a registry "Multi-Protocol Label Switching (MPLS)
   Label Switched Paths (LSPs) Ping Parameters" registry, and within
   that registry a sub-registry "Return Codes".

   IANA is requested to assign new Return Codes from the Standards
   Action range (0-191) as follows:

   +-------+-------------------------------------------+---------------+

   +---------------+-----------------------------------+---------------+
   | Error Value   | Meaning Description                       | Reference     |
   +-------+-------------------------------------------+---------------+
   | TBD2 Sub-codes     | MPLS OAM Unsupported Functionality                                   | This document               |
   +---------------+-----------------------------------+---------------+
   | TBD3 TBA3          | OAM Problem/Unsupported TX rate interval BFD       | This document |
   | TBD4               | Version                           |               |
   | TBA4          | OAM Problem/Unsupported RX rate interval BFD       | This document |
   | TBD5               | Encapsulation format              |               |
   | TBA5          | OAM Problem/Unsupported Authentication BFD       | This document |
   |               | Authentication Type               |               |
   | TBD6 TBA6          | OAM Problem mismatch Problem/Mismatch of Authentication BFD       | This document |
   |               | Authentication Key ID             |               |
   +-------+-------------------------------------------+---------------+
   | TBA7          | OAM Problem/Unsupported Timestamp | This document |
   |               | Format                            |               |
   | TBA8          | OAM Problem/Unsupported Delay     | This document |
   |               | Mode                              |               |
   | TBA9          | OAM Problem/Unsupported Loss Mode | This document |
   | TBA10         | OAM Problem/Delay variation       | This document |
   |               | unsupported                       |               |
   | TBA11         | OAM Problem/Dyadic mode           | This document |
   |               | unsupported                       |               |
   | TBA12         | OAM Problem/Loopback mode         | This document |
   |               | unsupported                       |               |
   | TBA13         | OAM Problem/Combined mode         | This document |
   |               | unsupported                       |               |
   | TBA14         | OAM Problem/Fault management      | This document |
   |               | signaling unsupported             |               |
   | TBA15         | OAM Problem/Unable to create      | This document |
   |               | fault management association      |               |
   +---------------+-----------------------------------+---------------+

                   Table 3: IANA Return Codes Allocation

4.

5.  Acknowledgements

   The authors would like to thank Nobo Akiya for his useful comments.

6.  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 were to request
   high frequency liveliness monitoring of a large number of LSPs,
   targeting a single network element.

5.

7.  References

5.1.

7.1.  Normative References

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

   [RFC3473]  Berger, L., "Generalized Multi-Protocol Label Switching
              (GMPLS) Signaling Resource ReserVation Protocol-Traffic
              Engineering (RSVP-TE) Extensions", RFC 3473, January 2003.

   [RFC4379]  Kompella, K. and G. Swallow, "Detecting Multi-Protocol
              Label Switched (MPLS) Data Plane Failures", RFC 4379,
              February 2006.

   [RFC5654]  Niven-Jenkins, B., Brungard, D., Betts, M., Sprecher, N.,
              and S. Ueno, "Requirements of an MPLS Transport Profile",
              RFC 5654, September 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.

   [RFC6370]  Bocci, M., Swallow, G., and E. Gray, "MPLS Transport
              Profile (MPLS-TP) Identifiers", RFC 6370, September 2011.

   [RFC6374]  Frost, D. and S. Bryant, "Packet Loss and Delay
              Measurement for MPLS Networks", RFC 6374, September 2011.

   [RFC6427]  Swallow, G., Fulignoli, A., Vigoureux, M., Boutros, S.,
              and D. Ward, "MPLS Fault Management Operations,
              Administration, and Maintenance (OAM)", RFC 6427, November
              2011.

   [RFC6428]  Allan, D., Swallow Ed. , G., and J. Drake Ed. , "Proactive
              Connectivity Verification, Continuity Check, and Remote
              Defect Indication for the MPLS Transport Profile", RFC
              6428, November 2011.

5.2.

7.2.  Informative References

   [RFC3209]  Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
              and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
              Tunnels", RFC 3209, December 2001.

   [RFC5036]  Andersson, L., Minei, I., and B. Thomas, "LDP
              Specification", RFC 5036, October 2007.

   [RFC5462]  Andersson, L. and R. Asati, "Multiprotocol Label Switching
              (MPLS) Label Stack Entry: "EXP" Field Renamed to "Traffic
              Class" Field", RFC 5462, February 2009.

   [RFC6371]  Busi, I. and D. Allan, "Operations, Administration, and
              Maintenance Framework for MPLS-Based Transport Networks",
              RFC 6371, September 2011.

   [RFC6375]  Frost, D. and S. Bryant, "A Packet Loss and Delay
              Measurement Profile for MPLS-Based Transport Networks",
              RFC 6375, September 2011.

   [RFC6669]  Sprecher, N. and L. Fang, "An Overview of the Operations,
              Administration, and Maintenance (OAM) Toolset for MPLS-
              Based Transport Networks", RFC 6669, July 2012.

   [RSVP-TE-CONF]
              Bellagamba, E., Andersson, L., Ward, D., and P.
              Skoldstrom, "Configuration of pro-active MPLS-TP
              Operations, Administration, and Maintenance (OAM)
              Functions Using RSVP-TE", 2012, <draft-ietf-ccamp-rsvp-te-
              mpls-tp-oam-ext>.

Authors' Addresses

   Elisa Bellagamba (editor)
   Ericsson

   Email: elisa.bellagamba@ericsson.com

   Gregory Mirsky (editor)
   Ericsson

   Email: Gregory.Mirsky@ericsson.com
   Loa Andersson
   Huawei Technologies

   Email: loa@mail01.huawei.com

   Pontus Skoldstrom (editor)
   Acreo AB
   Electrum 236
   Kista  164 40
   Sweden

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

   Dave Ward
   Cisco

   Email: dward@cisco.com

   John Drake
   Juniper

   Email: jdrake@juniper.net