# MPLS-TP

In telecommunications, Multiprotocol Label Switching - Transport Profile (MPLS-TP) is a variant of the MPLS protocol that is used in packet switched data networks. MPLS-TP is the 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.

## Description

MPLS-TP is designed for use as a network layer technology in transport networks. It will be a continuation of the work started by the transport network experts of the ITU-T, specifically SG15, as T-MPLS. Since 2008 the work is progressed in a cooperation between ITU-T and IETF. The required protocol extensions to MPLS being designed by the IETF based on requirements provided by service providers. It will be a connection-oriented packet-switched (CO-PS) application. It will offer a dedicated MPLS implementation by removing features that are not relevant to CO-PS applications and adding mechanisms that provide support of critical transport functionality.
MPLS-TP is to be based on the same architectural principles of layered networking that are used in longstanding transport network technologies like SDH, SONET and OTN. Service providers have already developed management processes and work procedures based on these principles.
MPLS-TP gives service providers a reliable packet-based technology that is based upon circuit-based transport networking, and thus is expected to align with current organizational processes and large-scale work procedures similar to other packet transport technologies.
MPLS-TP is a low cost L2.5 technology (if the limited profile to be specified is implemented in isolation) that provides QoS, end-to-end OA&M and protection switching.
In February 2008 the ITU-T and IETF agreed to work jointly on the design of MPLS-TP. Based on this agreement IETF and ITU-T experts will jointly work out the requirements and solutions. ITU-T in turn will update the existing T-MPLS standards based on the MPLS-TP related RFCs listed below.

## ITU-T

The following ITU-T Recommendations exist for MPLS-TP. Some of those Recommendations are superseding the ones that applied to T-MPLS before this work was ceased.
| Recommendation | Title |
| G.8110.1 | Architecture of the Multi-Protocol Label Switching transport profile layer network |
| G.8112 | Interfaces for the MPLS transport profile layer network |
| G.8113.1 | Operations, administration and maintenance mechanisms for MPLS-TP in packet transport networks |
| G.8113.2 | Operations, administration and maintenance mechanisms for MPLS-TP networks using the tools defined for MPLS |
| G.8121 | Characteristics of MPLS-TP equipment functional blocks |
| G.8121.1 | Characteristics of MPLS-TP equipment functional blocks supporting ITU-T G.8113.1/Y.1372.1 OAM mechanisms |
| G.8121.2 | Characteristics of MPLS-TP equipment functional blocks supporting ITU-T G.8113.2/Y.1372.2 OAM mechanisms |
| G.8131 | Linear protection switching for MPLS transport profile |
| G.8151 | Management aspects of the MPLS-TP network element |
| G.8152 | Protocol-neutral management information model for the MPLS-TP network element |

## RFC or drafts

The following IETF RFCs or drafts exist for MPLS-TP:
| RFC | Title | Draft |
| RFC 5317 | Joint Working Team (JWT) Report on MPLS Architectural Considerations for a Transport Profile | draft-bryant-mpls-tp-jwt-report |
| RFC 5586 | MPLS Generic Associated Channel | draft-ietf-mpls-tp-gach-gal |
| RFC 5654 | MPLS-TP Requirements | draft-ietf-mpls-tp-requirements |
| RFC 5718 | An In-Band Data Communication Network For the MPLS Transport Profile | draft-ietf-mpls-tp-gach-dcn |
| RFC 5860 | Requirements for Operations, Administration, and Maintenance (OAM) in MPLS Transport Networks | draft-ietf-mpls-tp-oam-requirements |
| RFC 5921 | A Framework for MPLS in Transport Networks | draft-ietf-mpls-tp-framework |
| RFC 5950 | Network Management Framework for MPLS-based Transport Networks | draft-ietf-mpls-tp-nm-framework |
| RFC 5951 | Network Management Requirements for MPLS-based Transport Networks | draft-ietf-mpls-tp-nm-req |
| RFC 5960 | MPLS Transport Profile Data Plane Architecture | draft-ietf-mpls-tp-data-plane |
| RFC 6215 | MPLS Transport Profile User-to-Network and Network-to-Network Interfaces | draft-ietf-mpls-tp-uni-nni |
| RFC 6291 | Guidelines for the Use of the "OAM" Acronym in the IETF | draft-ietf-opsawg-mpls-tp-oam-def |
| RFC 6370 | MPLS-TP Identifiers | draft-ietf-mpls-tp-identifiers |
| RFC 6371 | Operations, Administration, and Maintenance Framework for MPLS-Based Transport Networks | draft-ietf-mpls-tp-oam-framework |
| RFC 6372 | MPLS Transport Profile (MPLS-TP) Survivability Framework | draft-ietf-mpls-tp-survive-fwk |
| RFC 6373 | MPLS-TP Control Plane Framework | draft-ietf-ccamp-mpls-tp-cp-framework |
| RFC 6375 | A Packet Loss and Delay Measurement Profile for MPLS-based Transport Networks | draft-ietf-mpls-tp-loss-delay-profile |
| RFC 6669 | MPLS-TP OAM Analysis | draft-ietf-mpls-tp-oam-analysis |
| RFC 6426 | MPLS On-demand Connectivity Verification and Route Tracing | draft-ietf-mpls-tp-on-demand-cv |
| RFC 6378 | MPLS-TP Linear Protection | draft-ietf-mpls-tp-linear-protection |
| RFC 6427 | MPLS Fault Management OAM | draft-ietf-mpls-tp-fault |
| RFC 6428 | Proactive Connectivity Verification, Continuity Check and Remote Defect indication for MPLS Transport Profile | draft-ietf-mpls-tp-cc-cv-rdi |
| RFC 6478 | Pseudowire Status for Static Pseudowires | draft-ietf-pwe3-static-pw-status |
| RFC 6435 | MPLS Transport Profile lock Instruct and Loopback Functions | draft-ietf-mpls-tp-li-lb |

## Solutions

The solutions for the above requirements and framework are as mentioned below and is under development:
* RFC 5718 An In-Band Data Communication Network For the MPLS Transport Profile
* RFC 5586 MPLS Generic Associated Channel- Defines GAL/G-ACH
* RFC 5462 "EXP field" renamed to "Traffic Class field"
* RFC 6435 MPLS Transport Profile Lock Instruct and Loopback Functions
* RFC 7087 A Thesaurus for the Interpretation of Terminology Used in MPLS Transport Profile (MPLS-TP) Internet-Drafts and RFCs in the Context of the ITU-T's Transport Network Recommendation
* MPLS-TP ACH TLV (IETF Draft)
* Proactive continuity and connectivity verification (Individual Draft)
* RFC 6291 Guidelines for the Use of the "OAM" Acronym in the IETF
* MPLS-TP OAM based on Y.1731 (Individual Draft)
* MPLS-TP Performance monitoring (Individual Draft)
* RFC 6427 MPLS Fault Management Operations, Administration, and Maintenance (OAM)
* RFC 6378 MPLS Transport Profile (MPLS-TP) Linear Protection
* RFC 7347 Pre-standard Linear Protection Switching in MPLS Transport Profile (MPLS-TP)
* MPLS-TP P2MP traffic protection (Individual Draft)
* MPLS-TP OAM Alarm suppression (Individual Draft)
* MPLS-TP & IP/MPLS Interworking (Individual Draft)
* MPLS-TP Ring Protection (Individual Draft)
* MPLS-TP LDP extension: No work
* MPLS-TP RSVP-TE extensions: No work