| CCAMP Working Group | E.B. Bellagamba, Ed. |
| Internet-Draft | L.A. Andersson, Ed. |
| Intended status: Standards Track | Ericsson |
| Expires: June 15, 2013 | P.S. Skoldstrom, Ed. |
| Acreo AB | |
| D.W. Ward | |
| Cisco | |
| A.T. Takacs | |
| Ericsson | |
| December 12, 2012 |
Configuration of Pro-Active Operations, Administration, and Maintenance (OAM) Functions for MPLS-based Transport Networks using RSVP-TE
draft-ietf-ccamp-rsvp-te-mpls-tp-oam-ext-11
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 RSVP-TE protocol.
This document is a product of a joint Internet Engineering Task Force (IETF) / International Telecommunication Union Telecommunication Standardization Sector (ITU-T) effort to include an MPLS Transport Profile within the IETF MPLS and PWE3 architectures to support the capabilities and functionalities of a packet transport network.
This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http:/⁠/⁠datatracker.ietf.org/⁠drafts/⁠current/⁠.
Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."
This Internet-Draft will expire on June 15, 2013.
Copyright (c) 2012 IETF Trust and the persons identified as the document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http:/⁠/⁠trustee.ietf.org/⁠license-⁠info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.
This document describes the configuration of pro-active MPLS-TP Operations, Administration, and Maintenance (OAM) Functions for a given LSP using TLVs carried by RSVP-TE [RFC3473]. 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 such as RSVP-TE.
Pro-active MPLS-TP OAM is performed by four different protocols, Bi-directional Forwarding Detection (BFD) [RFC6428] for Continuity Check/Connectivity Verification, the delay measurement protocol (DM) [RFC6374] for delay and delay variation (jitter) measurements, and the loss measurement protocol (LM) [RFC6374] 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 track the liveliness and detect data plane failures of MPLS-TP point-to-point and might also be extended to support point-to-multipoint connections.
The delay and loss measurements protocols [RFC6374] use a simple query/response model for performing bidirectional measurements that allows the originating node to measure packet loss and delay in both 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 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.
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.
This document is a product of a joint Internet Engineering Task Force (IETF) / International Telecommunication Union Telecommunication Standardization Sector (ITU-T) effort to include an MPLS Transport Profile within the IETF MPLS and PWE3 architectures to support the capabilities and functionalities of a packet transport network.
This document is the result of a large team of authors and contributors. The following is a list of the co-authors:
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].
[RFC6371] describes how MPLS-TP OAM mechanisms are operated to meet transport requirements outlined in [RFC5860].
[RFC6428] 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.
[RFC6374] specifies mechanisms for performance monitoring of LSPs, in particular it specifies loss and delay measurement OAM functions.
[RFC6427] 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 Lock Report (LKR).
[RFC6371] 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 in a signal fail condition.
RSVP-TE, or alternatively LSP Ping [LSP-PING-CONF], can be used to simply enable the different OAM functions, by setting the corresponding flags in the "OAM Functions TLV". 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 OAM configuration TLVs but simply forward them to the end-node. There is one exception to this and that is if the "MPLS OAM FMS sub-TLV" is present. This sub-TLV has to be examined even by intermediate nodes. The sub-TLV MAY be present if a flag is set in the "Function Flags sub-TLV", see section [3.2. OAM Configuration TLV].
For this specification, BFD MUST be run in either one of the two modes:
In the simplest scenario RSVP-TE, or alternatively LSP Ping [LSP-PING-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 RSVP-TE signaling messages.
When BFD Control packets are transported in the G-ACh 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" 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" 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.
It is possible to configure Performance Monitoring functionalities such as Loss, Delay, 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 "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 "OAM Functions TLV" and including the "MPLS OAM PM Loss sub-TLV" one can configure the measurement interval and loss threshold values for triggering protection.
Delay measurements are configured by setting PM Delay flag in the "OAM Functions TLV" and including the "MPLS OAM PM Loss sub-TLV" one can configure the measurement interval and the delay threshold values for triggering protection.
To configure Fault Monitoring Signals and their refresh time the FMS flag in the "OAM Functions TLV" MUST be set and the "MPLS OAM FMS sub-TLV" included. When configuring Fault Monitoring Signals it can be chosen either the default configuration (by only setting the respective flags in the "OAM functions TLV") or a customized configuration (by including the "MPLS OAM FMS sub-TLV").
If an intermediate point is meant to originate fault management signal messages this means that such an intermediate point is associated to a server MEP through a co-located MPLS-TP client/server adaptation function. Such a server MEP needs to be configured by its own RSVP-TE session (or, alternatively, via an NMS or LSP-ping). However, by setting the "Fault Management subscription" flag in the "MPLS OAM 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.
The "OAM Configuration TLV", defined in [OAM-CONF-FWK], specifies the OAM functions that are used for the LSP. This TLV is carried in the LSP_ATTRIBUTES object in Path and Resv messages.
This document extends the "OAM Configuration TLV" by defining a new OAM Type: "MPLS OAM" (suggested value 2, IANA to assign) from the "RSVP-TE OAM Configuration Registry". The "MPLS OAM" type is set to request the establishment of OAM functions for MPLS-TP LSPs. The specific OAM functions are specified in the "Function Flags" sub-TLV as depicted in [OAM-CONF-FWK].
The receiving edge LSR when the MPLS-TP OAM Type is requested should check which OAM Function Flags are set in the "Function Flags TLV" (also defined in [OAM-CONF-FWK]) and look for the corresponding technology specific configuration TLVs.
Additional corresponding sub-TLVs are as follows:
Moreover, if the CV Flag is set, the CC flag MUST be set as well. The format of an MPLS-TP CV/CC message is shown in [RFC6428] and it requires, together with the BFD Control packet information, the "LSP MEP-ID". The "LSP MEP-ID" contain four identifiers:
These values need to be correctly set by both ingress and egress when transmitting a CV packet and both ingress and egress needs to know what to expect when receving a CV packet. Most of these values can be derived from the Path and Resv messages [RFC3473], which uses a 5-tuple to uniquely identify an LSP within an operator's network. This tuple is composed of a Tunnel Sender Address, Tunnel Endpoint Address, Tunnel_ID, Extended Tunnel ID, and and (GMPLS) LSP_ID.
However, not all the values can be derived from the standard RSVP-TE objects, in particular the locally assigned Tunnel ID at the egress cannot be derived by the ingress node. Therefor the full LSP MEP-ID used by the ingress has to be carried in the "BFD Identifiers sub-TLV" in the Path message and the egress LSP MEP-ID in the same way in the Resv message.
The "BFD Configuration sub-TLV" (depicted below) is defined for BFD OAM specific configuration parameters. The "BFD Configuration sub-TLV" is carried as a sub-TLV of the "OAM Configuration 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. Type (3) (IANA) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Vers.| PHB |N|S|I|G|U|B| Reserved (set to all 0s) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | ~ sub-TLVs ~ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: indicates a new type, the "BFD Configuration sub-TLV" (IANA to define, suggested value 3).
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".
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 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 UDP packets. If both the G bit and U bit are set, configuration gives precedence to the G bit.
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 Path message:
The "BFD Configuration sub-TLV" MUST include the following sub-TLVs in the Resv message:
The "BFD Identifiers sub-TLV" is carried as a sub-TLV of the "BFD Configuration sub-TLV" and 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | BFD ident. Type (1) (IANA) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Local Discriminator | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MPLS-TP Global_ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MPLS-TP Node Identifier | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tunnel_Num | LSP_Num | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: indicates a new type, the "BFD Identifiers sub-TLV" (1) (IANA to define).
Length: indicates the TLV total length in octets. (8)
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.
MPLS-TP Global_ID, Node Identifier, Tunnel_Num, and LSP_Num: all set as defined in [RFC6370].
The "Negotiation Timer Parameters sub-TLV" is carried as a sub-TLV of the "BFD Configuration sub-TLV" and 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Nego. Timer Type (2) (IANA) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Acceptable Min. Asynchronous TX interval | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Acceptable Min. Asynchronous RX interval | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Required Echo TX Interval | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: indicates a new type, the "Negotiation Timer Parameters sub-TLV" (IANA to define, suggested value 2).
Length: indicates the TLV total length in octets. (16)
Acceptable Min. Asynchronous TX interval: in case of S (symmetric) flag set in the "BFD Configuration sub-TLV", 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 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", 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 "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 support this value an error MUST be generated "Unsupported BFD TX rate interval".
The "BFD Authentication sub-TLV" is carried as a sub-TLV of the "BFD Configuration sub-TLV" and 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | BFD Auth. Type (3) (IANA) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Auth Type | Auth Key ID | Reserved (0s) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: indicates a new type, the "BFD Authentication sub-TLV" (IANA to define).
Length: indicates the TLV total length in octets. (8)
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.
Reserved: Reserved for future specification and set to 0 on transmission and ignored when received.
If the "OAM functions TLV" has either the L (Loss), D (Delay) or T (Throughput) flag set, the "Performance Monitoring sub-TLV" MUST be present.
The "Performance Monitoring sub-TLV" provides the configuration information mentioned in Section 7 of [RFC6374]. It includes support for the configuration of quality thresholds and, as described in [RFC6374], "the crossing of which will trigger warnings or alarms, and result reporting and exception notification will be integrated into the system-wide network management and reporting framework."
In case the values need to be different than the default ones the "Performance Monitoring sub-TLV", "MPLS OAM PM Loss sub-TLV" MAY include the following sub-TLVs:
The "Performance Monitoring sub-TLV" depicted below is carried as a sub-TLV of the "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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Perf Monitoring Type(4) (IANA)| Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |D|L|J|Y|K|C| Reserved (set to all 0s) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | ~ sub-TLVs ~ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: indicates a new type, the "Performance Monitoring sub-TLV" (IANA to define, suggested value 4).
Length: indicates the TLV total length in octets.
Configuration Flags, for the specific function description please refer to [RFC6374]:
Reserved: Reserved for future specification and set to 0 on transmission and ignored when received.
The "MPLS OAM PM Loss sub-TLV" depicted below is carried as a sub-TLV of the "Performance Monitoring 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 Loss Type (1) (IANA) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | OTF |T|B| Reserved (set to all 0s) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Measurement Interval | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Test Interval | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Loss Threshold | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: indicates a new type, the "MPLS OAM PM Loss sub-TLV" (IANA to define, suggested value 1).
Length: indicates the length of the parameters in octets (20).
OTF: Origin Timestamp Format of the Origin Timestamp field described in [RFC6374]. By default it is set to IEEE 1588 version 1.
Configuration Flags, please refer to [RFC6374] for further details:
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.
The "MPLS OAM PM Delay sub-TLV" depicted below is carried as a sub-TLV of the "Performance Monitoring 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 (2) (IANA) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | OTF |T|B| Reserved (set to all 0s) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Measurement Interval | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Test Interval | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Delay Threshold | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: indicates a new type, the "MPLS OAM PM Loss sub-TLV" (IANA to define, suggested value 2).
Length: indicates the length of the parameters in octets (20).
OTF: Origin Timestamp Format of the Origin Timestamp field described in [RFC6374]. By default it is set to IEEE 1588 version 1.
Configuration Flags, please refer to [RFC6374] for further details:
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 Measurement query messages MUST be sent on both directions. If the edge LSR receiving the Path message can not support such value, it can reply with a higher 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 threshold value of measured two-way delay (in milliseconds) over which action(s) SHOULD be triggered.
The "MPLS OAM FMS sub-TLV" depicted below is carried as a sub-TLV of the "OAM Configuration sub-TLV". When both working and protection paths are signaled, both LSPs SHOULD be signaled 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MPLS OAM FMS Type (5) (IANA) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |E|S|T| Reserved (set to all 0s)| Refresh Timer | PHB | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: indicates a new type, the "MPLS OAM FMS sub-TLV" (IANA to define).
Length: indicates the TLV total length in octets. (8)
FMS Signal Flags are used to enable the FMS signals at end point MEPs and 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:
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 can not support the value it SHOULD reply with a higher timer value.
PHB: identifies the per-hop behavior of packets with fault management information.
This document specifies the following new TLV types:
sub-TLV types to be carried in the "BFD Configuration sub-TLV":
sub-TLV types to be carried in the "Performance monitoring sub-TLV":
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:
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.
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.