Generic Associated Channel (G-ACh) Parameters

Created

  • 2014-02-07

Last Updated

  • 2026-09-28

Available Formats

MPLS Generalized Associated Channel (G-ACh) Types (including Pseudowire Associated Channel Types)

Registration Procedure(s)

  • IETF Review

Reference

  • RFC 4385: Pseudowire Emulation Edge-to-Edge (PWE3) Control Word for Use over an MPLS PSN
  • RFC 5586: MPLS Generic Associated Channel
  • RFC Errata 1940
  • RFC 7026: Retiring TLVs from the Associated Channel Header of the MPLS Generic Associated Channel
  • RFC 7214: Moving Generic Associated Channel (G-ACh) IANA Registries to a New Registry

Available Formats

Value Description Reference
0x0000 Reserved
0x0001 Management Communication Channel (MCC) RFC 5718
0x0002 Signaling Communication Channel (SCC) RFC 5718
0x0003-0x0006 Unassigned
0x0007 BFD Control, PW-ACH encapsulation (without IP/UDP Headers) RFC 5885
0x0008 S-BFD Control, PW-ACH/L2SS encapsulation (without IP/UDP Headers) RFC 7885
0x0009 MPLS-TP Dual-Homing Coordination message RFC 8185
0x000A MPLS Direct Loss Measurement (DLM) RFC 6374
0x000B MPLS Inferred Loss Measurement (ILM) RFC 6374
0x000C MPLS Delay Measurement (DM) RFC 6374
0x000D MPLS Direct Loss and Delay Measurement (DLM+DM) RFC 6374
0x000E MPLS Inferred Loss and Delay Measurement (ILM+DM) RFC 6374
0x000F Residence Time Measurement RFC 8169
0x0010 Time Bucket Jitter Measurement RFC 9571
0x0011 Multi-packet Delay Measurement RFC 9571
0x0012 Average Delay Measurement RFC 9571
0x0013 Multipoint BFD Session RFC 9780
0x0014 STAMP Session-Sender RFC-ietf-mpls-stamp-pw-21
0x0015 STAMP Session-Reflector RFC-ietf-mpls-stamp-pw-21
0x0016-0x0020 Unassigned
0x0021 Associated Channel carries an IPv4 packet RFC 4385
0x0022 MPLS-TP CC message RFC 6428
0x0023 MPLS-TP CV message RFC 6428
0x0024 Protection State Coordination Protocol - Channel Type (PSC-CT) RFC 6378
0x0025 On-Demand CV RFC 6426
0x0026 LI RFC 6435
0x0027 PW OAM Message RFC 6478
0x0028 MAC Withdraw OAM Message RFC 7769
0x0029 PW Status Refresh Reduction RFC 8237
0x002A Ring Protection Switching (RPS) Protocol RFC 8227
0x002B-0x0056 Unassigned
0x0057 Associated Channel carries an IPv6 packet RFC 4385
0x0058 Fault OAM RFC 6427
0x0059 G-ACh Advertisement Protocol RFC 7212
0x005A-0x7FF7 Unassigned
0x7FF8-0x7FFF Reserved for Experimental Use RFC 5586
0x8000-0x8901 Unassigned
0x8902 G.8113.1 OAM RFC 6671
0x8903-0xFFFF Unassigned

G-ACh Advertisement Protocol Application Registry

Registration Procedure(s)

  • IETF Review

Reference

  • RFC 7212: MPLS Generic Associated Channel (G-ACh) Advertisement Protocol
  • RFC 7214: Moving Generic Associated Channel (G-ACh) IANA Registries to a New Registry

Available Formats

Application ID Description Reference
0x0000 G-ACh Advertisement Protocol RFC 7212
0x0001 Ethernet Interface Parameters RFC 7213
0x0002-0xFFFF Unassigned

G-ACh Advertisement Protocol: GAP TLV Objects (Application ID 0)

Registration Procedure(s)

  • IETF Review

Reference

  • RFC 7212: MPLS Generic Associated Channel (G-ACh) Advertisement Protocol
  • RFC 7214: Moving Generic Associated Channel (G-ACh) IANA Registries to a New Registry

Available Formats

Type ID Type Name Reference
0 Source Address RFC 7212
1 GAP Request RFC 7212
2 GAP Flush RFC 7212
3 GAP Suppress RFC 7212
4 GAP Authentication RFC 7212
5-255 Unassigned

G-ACh Advertisement Protocol: Ethernet Interface Parameters

Registration Procedure(s)

  • IETF Review or IESG Approval

Reference

  • RFC 7213: MPLS Transport Profile (MPLS-TP) Next-Hop Ethernet Addressing
  • RFC 7214: Moving Generic Associated Channel (G-ACh) IANA Registries to a New Registry

Available Formats

Type ID Type Name Reference
0 Source MAC Address RFC 7213
1 Maximum Frame Size RFC 7213
2-255 Unassigned

CC/CV MEP-ID TLV Registry

Registration Procedure(s)

  • Standards Action

Reference

  • RFC 6428: Proactive Connectivity Verification, Continuity Check, and Remote Defect Indication for the MPLS Transport Profile
  • RFC 7214: Moving Generic Associated Channel (G-ACh) IANA Registries to a New Registry

Available Formats

Value Name Reference
0 Section MEP-ID RFC 6428
1 LSP MEP-ID RFC 6428
2 PW MEP-ID RFC 6428
3-255 Unassigned

Measurement Timestamp Type

Registration Procedure(s)

  • IETF Review

Reference

  • RFC 6374: Packet Loss and Delay Measurement for MPLS Networks
  • RFC 7214: Moving Generic Associated Channel (G-ACh) IANA Registries to a New Registry

Available Formats

Type Description Size in Bits Reference
0 Null Timestamp 64 RFC 6374
1 Sequence Number 64 RFC 6374
2 Network Time Protocol version 4 64-bit Timestamp 64 RFC 6374
3 Truncated IEEE 1588v2 PTP Timestamp 64 RFC 6374
4-15 Unassigned

Loss/Delay Measurement Control Code: Query Codes

Registration Procedure(s)

  • IETF Review

Reference

  • RFC 6374: Packet Loss and Delay Measurement for MPLS Networks
  • RFC 7214: Moving Generic Associated Channel (G-ACh) IANA Registries to a New Registry

Available Formats

Code Description Reference
0x0 In-band Response Requested RFC 6374
0x1 Out-of-band Response Requested RFC 6374
0x2 No Response Requested RFC 6374
0x3-0xFF Unassigned

Loss/Delay Measurement Control Code: Response Codes

Registration Procedure(s)

  • IETF Review

Reference

  • RFC 6374: Packet Loss and Delay Measurement for MPLS Networks
  • RFC 7214: Moving Generic Associated Channel (G-ACh) IANA Registries to a New Registry

Note

Values 0x0-0xF are reserved for non-error response codes; please refer to Section 4.1 of RFC 6374 for guidelines.

Available Formats

Code Description Reference
0x0 Reserved RFC 6374
0x1 Success RFC 6374
0x2 Data Format Invalid RFC 6374
0x3 Initialization in Progress RFC 6374
0x4 Data Reset Occurred RFC 6374
0x5 Resource Temporarily Unavailable RFC 6374
0x6-0xF Unassigned
0x10 Unspecified Error RFC 6374
0x11 Unsupported Version RFC 6374
0x12 Unsupported Control Code RFC 6374
0x13 Unsupported Data Format RFC 6374
0x14 Authentication Failure RFC 6374
0x15 Invalid Destination Node Identifier RFC 6374
0x16 Connection Mismatch RFC 6374
0x17 Unsupported Mandatory TLV Object RFC 6374
0x18 Unsupported Query Interval RFC 6374
0x19 Administrative Block RFC 6374
0x1A Resource Unavailable RFC 6374
0x1B Resource Released RFC 6374
0x1C Invalid Message RFC 6374
0x1D Protocol Error RFC 6374
0x1E-0xFF Unassigned

MPLS Loss/Delay Measurement TLV Object

Registration Procedure(s)

  • IETF Review

Reference

  • RFC 6374: Packet Loss and Delay Measurement for MPLS Networks
  • RFC 7214: Moving Generic Associated Channel (G-ACh) IANA Registries to a New Registry

Note

Types 0-127 are classified as Mandatory, and Types 128-255 are classified as Optional.

Available Formats

Code Description Reference
0 Padding - copy in response RFC 6374
1 Return Address RFC 6374
2 Session Query Interval RFC 6374
3 Loopback Request RFC 6374
4 Synonymous Flow Label RFC 9571
5 Return Path RFC 9779
6 Block Number RFC 9779
7-126 Unassigned
127 Experimental use RFC 6374
128 Padding - do not copy in response RFC 6374
129 Destination Address RFC 6374
130 Source Address RFC 6374
131 UDP Return RFC 7876
132-254 Unassigned
255 Experimental use RFC 6374

Return Path Sub-TLV Types

Reference

  • RFC 9779: Performance Measurement for Segment Routing Networks with the MPLS Data Plane

Available Formats

Range Registration Procedures
1-175 IETF Review
176-239 First Come First Served
240-251 Experimental Use
252-254 Private Use
Value Description Reference
0 Reserved RFC 9779
1 MPLS Label Stack of the Return Path RFC 9779
2-239 Unassigned
240-251 Reserved for Experimental Use RFC 9779
252-254 Reserved for Private Use RFC 9779
255 Reserved RFC 9779

MPLS Fault OAM Message Type Registry

Registration Procedure(s)

  • Standards Action

Reference

  • RFC 6427: MPLS Fault Management Operations, Administration, and Maintenance (OAM)
  • RFC 7214: Moving Generic Associated Channel (G-ACh) IANA Registries to a New Registry

Available Formats

Msg Type Description Reference
0 Reserved RFC 6427
1 Alarm Indication Signal (AIS) RFC 6427
2 Lock Report (LKR) RFC 6427
3-251 Unassigned
252-255 Reserved for Experimental Use RFC 6427

MPLS Fault OAM Flag Registry

Registration Procedure(s)

  • Standards Action

Reference

  • RFC 6427: MPLS Fault Management Operations, Administration, and Maintenance (OAM)
  • RFC 7214: Moving Generic Associated Channel (G-ACh) IANA Registries to a New Registry

Available Formats

Bit Hex Description Reference
0-5 Unassigned
6 0x2 L-Flag RFC 6427
7 0x1 R-Flag RFC 6427

MPLS Fault OAM TLV Registry

Expert(s)

  • Unassigned

Reference

  • RFC 6427: MPLS Fault Management Operations, Administration, and Maintenance (OAM)
  • RFC 7214: Moving Generic Associated Channel (G-ACh) IANA Registries to a New Registry

Available Formats

Range Registration Procedures
0-191 Standards Action
192-247 Specification Required
Value TLV Name Reference
0 Reserved RFC 6427
1 Interface Identifier TLV RFC 6427
2 Global Identifier RFC 6427
3-247 Unassigned
248-255 Reserved for Experimental Use RFC 6427

MPLS PSC Request Registry

Registration Procedure(s)

  • Standards Action

Reference

  • RFC 6378: MPLS Transport Profile (MPLS-TP) Linear Protection
  • RFC 7214: Moving Generic Associated Channel (G-ACh) IANA Registries to a New Registry

Available Formats

Value Description Reference
0 No Request RFC 6378
1 Do-not-Revert RFC 6378
2 Reverse Request RFC 7271
3 Exercise RFC 7271
4 Wait-to-Restore RFC 6378
5 Manual Switch RFC 6378
6 Unassigned
7 Signal Degrade RFC 6378
8-9 Unassigned
10 Signal Fail RFC 6378
11 Unassigned
12 Forced Switch RFC 6378
13 Unassigned
14 Lockout of protection RFC 6378
15 Unassigned

MPLS PSC TLV Registry

Registration Procedure(s)

  • IETF Review

Reference

  • RFC 6378: MPLS Transport Profile (MPLS-TP) Linear Protection
  • RFC 7214: Moving Generic Associated Channel (G-ACh) IANA Registries to a New Registry

Available Formats

Value Description Reference
0 Reserved, not to be allocated RFC 6378; RFC 7324
1 Capabilities RFC 7271
2-65535 Unassigned

MPLS PSC Capability Flag Registry

Registration Procedure(s)

  • Standards Action

Reference

  • RFC 7271: MPLS Transport Profile (MPLS-TP) Linear Protection to Match the Operational Expectations of Synchronous Digital Hierarchy, Optical Transport Network, and Ethernet Transport Network Operators

Available Formats

Bit Hex Value Capability Reference
0 0x80000000 priority modification RFC 7271
1 0x40000000 non-revertive behavior modification RFC 7271
2 0x20000000 support of MS-W command RFC 7271
3 0x10000000 support of protection against SD RFC 7271
4 0x08000000 support of EXER command RFC 7271
5-31 Unassigned

MPLS RTM TLV Registry

Reference

  • RFC 8169: Residence Time Measurement in MPLS Networks

Available Formats

Range Registration Procedures
0-127 IETF Review
128-191 First Come First Served
Value Description Reference
0 Reserved RFC 8169
1 No payload RFC 8169
2 PTPv2, Ethernet encapsulation RFC 8169
3 PTPv2, IPv4 encapsulation RFC 8169
4 PTPv2, IPv6 encapsulation RFC 8169
5 NTP RFC 8169
6-191 Unassigned
192-254 Reserved for Private Use RFC 8169
255 Reserved RFC 8169

MPLS RTM Sub-TLV Registry

Reference

  • RFC 8169: Residence Time Measurement in MPLS Networks

Available Formats

Range Registration Procedures
0-127 IETF Review
128-191 First Come First Served
Value Description Reference
0 Reserved RFC 8169
1 PTP RFC 8169
2-191 Unassigned
192-254 Reserved for Private Use RFC 8169
255 Reserved RFC 8169

MPLS-TP DHC TLVs

Registration Procedure(s)

  • IETF Review

Reference

  • RFC 8185: Dual-Homing Coordination for MPLS Transport Profile (MPLS-TP) Pseudowires Protection

Available Formats

Type Description Length Reference
0x0000 Reserved RFC 8185
0x0001 PW Status 20 bytes RFC 8185
0x0002 Dual-Node Switching 16 bytes RFC 8185
0x0003-0xFFFF Unassigned

MPLS RPS Request Code Registry

Registration Procedure(s)

  • Specification Required

Expert(s)

  • Weiqiang Cheng, Jie Dong

Reference

  • RFC 8227: MPLS-TP Shared-Ring Protection (MSRP) Mechanism for Ring Topology

Available Formats

Value Description Reference
0 No Request (NR) RFC 8227
1 Reverse Request (RR) RFC 8227
2 Unassigned
3 Exercise (EXER) RFC 8227
4 Unassigned
5 Wait-to-Restore (WTR) RFC 8227
6 Manual Switch (MS) RFC 8227
7-10 Unassigned
11 Signal Fail (SF) RFC 8227
12 Unassigned
13 Forced Switch (FS) RFC 8227
14 Unassigned
15 Lockout of Protection (LP) RFC 8227
16-254 Unassigned
255 Reserved RFC 8227