2003-03 2024-09-02 Unless otherwise noted, the registrations in this registry are applicable in the context of the IETF Vendor ID . Expert Review Carlos Pignataro (primary), Ignacio Goyret (secondary) To maximize extensibility while still permitting interoperability, a uniform method for encoding message types and bodies is used throughout L2TP. This encoding will be termed AVP (Attribute-Value Pair). 0 Message Type AVP Also, see Message Type AVP values below 1 Result Code AVP Also, see Result Code AVP values below 2 Protocol Version AVP 3 Framing Capabilities AVP Also, see Framing Field definition below 4 Bearer Capabilities AVP Also, see Bearer Field definition below 5 Tie Breaker AVP 6 Firmware Revision AVP 7 Host Name AVP 8 Vendor Name AVP 9 Assigned Tunnel ID AVP 10 Receive Window Size AVP 11 Challenge AVP 12 Q.931 Cause Code AVP 13 Response AVP 14 Assigned Session ID AVP 15 Call Serial Number AVP 16 Minimum BPS AVP 17 Maximum BPS AVP 18 Bearer Type AVP Also, see Bearer Field definition below 19 Framing Type AVP Also, see Framing Field definition below 20 Reserved 21 Called Number AVP 22 Calling Number AVP 23 Sub-Address AVP 24 (Tx) Connect Speed BPS AVP 25 Physical Channel ID AVP 26 Initial Received LCP CONFREQ AVP 27 Last Sent LCP CONFREQ AVP 28 Last Received LCP CONFREQ AVP 29 Proxy Authen Type AVP Also, see Proxy Authen Type AVP Values below 30 Proxy Authen Name AVP 31 Proxy Authen Challenge AVP 32 Proxy Authen ID AVP 33 Proxy Authen Response AVP 34 Call Errors AVP 35 ACCM AVP 36 Random Vector AVP 37 Private Group ID AVP 38 Rx Connect Speed AVP 39 Sequencing Required AVP 40 Rx Minimum BPS 41 Rx Maximum BPS 42 Service Category Also, see Service Category AVP Flag Fields below 43 Service Name 44 Calling Sub-Address 45 VPI/VCI Identifier 46 PPP Disconnect Cause Code Also, see PPP Disconnect Cause Code Values below 47 CCDS AVP 48 SDS AVP 49 LCP Want Options 50 LCP Allow Options 51 LNS Last Sent LCP Confreq 52 LNS Last Received LCP Confreq 53 Modem On-Hold Capable AVP 54 Modem On-Hold Status AVP 55 PPPoE Relay AVP 56 PPPoE Relay Response Capability AVP 57 PPPoE Relay Forward Capability AVP 58 Extended Vendor ID AVP 59 Message Digest 60 Router ID 61 Assigned Control Connection ID 62 Pseudowire Capabilities List 63 Local Session ID 64 Remote Session ID 65 Assigned Cookie 66 Remote End ID 67 Application Code 68 Pseudowire Type 69 L2-Specific Sublayer 70 Data Sequencing 71 Circuit Status 72 Preferred Language 73 Control Message Authentication Nonce 74 Tx Connect Speed 75 Rx Connect Speed 76 Failover Capability 77 Tunnel Recovery 78 Suggested Control Sequence 79 Failover Session State 80 Multicast Capability 81 New Outgoing Sessions 82 New Outgoing Sessions Acknowledgement 83 Withdraw Outgoing Sessions 84 Multicast Packets Priority 85 Frame-Relay Header Length 86 ATM Maximum Concatenated Cells AVP 87 OAM Emulation Required AVP 88 ATM Alarm Status AVP Also, see ATM Alarm Status AVP Values below 89 Attachment Group Identifier 90 Local End Identifier 91 Interface Maximum Transmission Unit 92 FCS Retention 93 Tunnel Switching Aggregator ID AVP 94 Maximum Receive Unit (MRU) AVP 95 Maximum Reassembled Receive Unit (MRRU) AVP 96 VCCV Capability AVP 97 Connect Speed Update AVP 98 Connect Speed Update Enable AVP 99 TDM Pseudowire AVP 100 RTP AVP 101 PW Switching Point AVP 102 S-BFD Target Discriminator ID 103 ECN Capability 104-65535 Unassigned Expert Review Carlos Pignataro (primary), Ignacio Goyret (secondary) 0 (reserved) 1 (SCCRQ) Start-Control-Connection-Request 2 (SCCRP) Start-Control-Connection-Reply 3 (SCCCN) Start-Control-Connection-Connected 4 (StopCCN) Stop-Control-Connection-Notification 5 (reserved) 6 (HELLO) Hello 20 (ACK) Explicit Acknowledgement 7 (OCRQ) Outgoing-Call-Request 8 (OCRP) Outgoing-Call-Reply 9 (OCCN) Outgoing-Call-Connected 10 (ICRQ) Incoming-Call-Request 11 (ICRP) Incoming-Call-Reply 12 (ICCN) Incoming-Call-Connected 13 (reserved) 14 (CDN) Call-Disconnect-Notify 15 (WEN) WAN-Error-Notify 16 (SLI) Set-Link-Info 17 (MDMST) Modem Status 18 (SRRQ) Service Relay Request Message 19 (SRRP) Service Relay Reply Message 23 (MSRQ) Multicast-Session-Request 24 (MSRP) Multicast-Session-Response 25 (MSE) Multicast-Session-Establishment 26 (MSI) Multicast-Session-Information 27 (MSEN) Multicast-Session-End-Notify 21 (FSQ) Failover Session Query 22 (FSR) Failover Session Response 28 (CSUN) Connect-Speed-Update-Notification 29 (CSURQ) Connect-Speed-Update-Request Expert Review Carlos Pignataro (primary), Ignacio Goyret (secondary) 0 Reserved 1 General request to clear control connection 2 General error--Error Code indicates the problem 3 Control channel already exists 4 Requester is not authorized to establish a control channel 5 The protocol version of the requester is not supported Error Code indicates highest version supported 6 Requester is being shut down 7 Finite State Machine error 8 Control connection due to mismatching CCDS value 0 Reserved 1 Call/Session disconnected due to loss of carrier 2 Call/Session disconnected for the reason indicated in error code 3 Call/Session disconnected for administrative reasons 4 Call/Session failed due to lack of appropriate facilities being available (temporary condition) 5 Call/Session failed due to lack of appropriate facilities being available (permanent condition) 6 Invalid destination 7 Call failed due to no carrier detected 8 Call failed due to detection of a busy signal 9 Call failed due to lack of a dial tone 10 Call was not established within time allotted by LAC 11 Call was connected but no appropriate framing was detected 12 Disconnecting call due to mismatching SDS value 13 Session not established due to losing tie breaker (L2TPv3) 14 Session not established due to unsupported PW type (L2TPv3) 15 Session not established, sequencing required without valid L2-Specific Sublayer (L2TPv3). 16 Finite state machine error or timeout. 17 FR PVC was deleted permanently (no longer provisioned) 18 FR PVC has been INACTIVE for an extended period of time 19 Mismatched FR Header Length 20 HDLC Link was deleted permanently (no longer provisioned) 21 HDLC Link has been INACTIVE for an extended period of time 22 Session not established due to other LCCE can not support the OAM Cell Emulation 23 Mismatching interface MTU 24 Attempt to connect to non-existent forwarder 25 Attempt to connect to unauthorized forwarder 26 Loop Detected 27 Attachment Circuit bound to different PE 28 Attachment Circuit bound to different remote Attachment Circuit 29 Unassigned 30 Return code to indicate connection was refused because of TDM PW parameters. The error code indicates the problem. 31 Sequencing not supported 0 Reserved 1 No multicast traffic for the group 2 Session terminated for the reason indicated in the error code 3 No more receivers 4 No more receivers (filter-mode change) 0 No general error 1 No control connection exists yet for this LAC-LNS pair 2 Length is wrong 3 One of the field values was out of range or reserved field was non-zero 4 Insufficient resources to handle this operation now 5 The Session ID is invalid in this context 6 A generic vendor-specific error occurred in the LAC 7 Try another. If LAC is aware of other possible LNS destinations, it should try one of them. This can be used to guide an LAC based on LNS policy, for instance, the existence of multilink PPP bundles. 8 Session or tunnel was shutdown due to receipt of an unknown AVP with the M-bit set (see section 4.2). The Error Message SHOULD contain the attribute of the offending AVP in (human readable) text form. 9 Try another directed. If an LAC or LNS is aware of other possible destinations, it should inform the initiator of the control connection or session. The Error Message MUST contain a comma-separated list of addresses from which the initiator may choose. If the L2TP data channel runs over IPv4, then this would be a comma-separated list of IP addresses in the canonical dotted-decimal format (e.g., "192.0.2.1, 192.0.2.2, 192.0.2.3") in the UTF-8 charset using the Default Language . If there are no servers for the LAC or LNS to suggest, then Error Code 7 should be used. For IPv4, the delimiter between addresses MUST be precisely a single comma and a single space. For IPv6, each literal address MUST be enclosed in "[" and "]" characters, following the encoding described in . 10 Next hop unreachable. This identifies an error condition explicitly in the multi-TSA environment. 11 Next hop busy. This identifies an error condition explicitly in the multi-TSA environment. 12 TSA busy. This identifies an error condition explicitly in the multi-TSA environment. 0 Reserved 1 Bit Rate values disagree. 2 Different trunk types in the case of trunk-specific CESoPSN with CAS. 3 Requested payload size too big or too small. 4 RTP header cannot be generated. 5 Requested timestamp clock frequency cannot be generated. First Come First Served 0 Reserved 1 Textual username/password exchange 2 PPP CHAP 3 PPP PAP 4 No Authentication 5 Microsoft CHAP Version 1 (MSCHAPv1) 6 Reserved 7 EAP Specification Required Carlos Pignataro (primary), Ignacio Goyret (secondary) The Attribute Value field is a 16-bit field. 0x0001 S-bit (real-time) 0-32767 IESG Approval 32768-65279 First Come First Served 65280-65535 Reserved for Private or Experimental Use 0 No information available 1 Administrative disconnect. 2 Link Control Protocol (LCP) renegotiation at LNS disabled; LNS expects proxy LCP information, LAC did not send it. 3 Normal Disconnection, LCP Terminate-Request sent. Valid Direction values are: 1: LCP Terminate-Request sent by peer 2: LCP Terminate-Request sent by local 4 Compulsory encryption required by a PPP peer was refused by the other. Valid Direction values are: 1: Required by local; refused by peer 2: Required by peer; refused by local 5 FSM (Finite State Machine) Timeout error. (PPP event "TO-".) 6 No recognizable LCP packets were received. 7 LCP failure: Magic Number error; link possibly looped back. 8 LCP link failure: Echo Request timeout. 9 Peer has unexpected Endpoint-Discriminator for existing Multilink PPP (MP) bundle. 10 Peer has unexpected MRRU for existing MP bundle. 11 Peer has unexpected Short-Sequence-Number option for existing MP bundle. 12 Compulsory call-back required by a PPP peer was refused by the other. Valid Direction values are: 1: Required by local; refused by peer 2: Required by peer; refused by local 13 FSM Timeout error. 14 Peer has unexpected authenticated name for existing MP bundle. 15 PPP authentication failure: Authentication protocol unacceptable. Valid Direction values are: 1: All local authentication protocols were rejected by the peer. 2: All authentication protocols requested by peer were unacceptable or unimplemented locally. 16 PPP authentication failure: Authentication failed (bad name, password, or secret). Valid Direction values are: 1: Authentication of peer identity by local system. 2: Authentication of local identity by peer system. 17 FSM Timeout error. 18 No NCPs available (all disabled or rejected); no NCPs went to Opened state. (Control Protocol Number may be zero only if neither peer has enabled NCPs.) 19 NCP failure: failed to converge on acceptable addresses. Valid Direction values are: 1: Too many Configure-Naks received from peer. 2: Too many Configure-Naks sent to peer. 20 NCP failure: user not permitted to use any addresses. Valid Direction values are: 1: Local link address not acceptable to peer. 2: Remote link address not acceptable to local system. 21-32767 Unassigned (by IESG Approval) 32768-65279 Unassigned (First Come First Served) 65280-65535 Private or Experimental Use Expert Review Carlos Pignataro (primary), Ignacio Goyret (secondary) 0 Reserved 1 No alarm or alarm cleared (default for Active Status) 2 Unspecified or unknown Alarm Received (default for Inactive Status) 3 ATM Circuit received F1 Alarm on ingress LCCE 4 ATM Circuit received F2 Alarm on ingress LCCE 5 ATM Circuit received F3 Alarm on ingress LCCE 6 ATM Circuit received F4 Alarm on ingress LCCE 7 ATM Circuit received F5 Alarm on ingress LCCE 8 ATM Circuit down due to ATM Port shutdown on Peer LCCE 9 ATM Circuit down due to loop-back timeout on ingress LCCE 0 Reserved 1 No Alarm type specified (default) 2 Alarm Indication Signal (AIS) 3 Remote Defect Indicator (RDI) 4 Loss of Signal (LOS) 5 Loss of pointer (LOP) 6 Loss of framer (LOF) 7 loopback cells (LB) 8 Continuity Check (CC) IETF Review Bit numbering: In this sub-registry, the most significant (high order) bit is labeled Bit 7, and the least significant (low order) bit is labeled Bit 0, see parenthetical "Value". 0 L2-Specific Sublayer with V-bit set 1 Reserved 2 Reserved 3 Reserved 4 Reserved 5 Reserved 6 Reserved 7 Reserved 0 ICMP Ping 1 Reserved 2 BFD IP/UDP-encapsulated, for PW Fault Detection only 3 BFD IP/UDP-encapsulated, for PW Fault Detection and AC/PW Fault Status Signaling 4 BFD PW-ACH-encapsulated, for PW Fault Detection only 5 BFD PW-ACH-encapsulated, for PW Fault Detection and AC/PW Fault Status Signaling 6 S-BFD IP/UDP-encapsulated, for PW Fault Detection only 7 S-BFD L2SS-encapsulated, for PW Fault Detection only Standards Action The Bearer field is used by the Bearer Capabilities and Bearer Type AVPs. It is a 32-bit bit field, with current defined bit values of: 0x00000001 D-bit (Digital access requested) 0x00000002 A-bit (Analogue access requested) 0x00000004 B-bit (ATM Bearer support) Standards Action The Framing field is used by the Framing Capabilities and Framing Type AVPs. It is a 32-bit bit field, with current defined bit values of: 0x00000001 S-bit (synchronous framing) 0x00000002 A-bit (asyncronous framing) Standards Action There are six bits at the beginning of the L2TP AVP header. L2TPv2 and L2TPv3 share a common registry for the definitions of the six leading bits. 0 Mandatory Bit, "M-bit" 1 Hidden Bit, "H-bit" 2 Reserved 3 Reserved 4 Reserved 5 Reserved Standards Action There are 12 bits at the beginning of the L2TP Message Header. L2TPv2 and L2TPv3 share a common registry for the definitions of the 12 leading bits. 0 Message Type, "T-bit" 1 Length Field is Present, "L-bit" 2 Reserved 3 Reserved 4 Sequence Numbers Present, "S-bit" 5 Reserved 6 Offset Field is Present 7 Priority Bit, "P-bit" 8 B (Fragmentation) bit 9 E (Fragmentation) bit 10 Reserved 11 Reserved Carlos Pignataro (primary), Ignacio Goyret (secondary) The Pseudowire Type (PW Type, Section 5.4) is a two-octet value used in the Pseudowire Type AVP and Pseudowire Capabilities List AVP defined in Section 5.4.3. There are no specific pseudowire types assigned within this document. Each pseudowire-specific document must allocate its own PW types from IANA as necessary. 0-32767 Expert Review 32768-65535 First Come First Served 0x0001 Frame Relay DLCI Pseudowire Type 0x0002 ATM AAL5 SDU VCC transport 0x0003 ATM Cell transparent Port Mode 0x0004 Ethernet VLAN Pseudowire Type 0x0005 Ethernet Pseudowire Type 0x0006 HDLC Pseudowire Type 0x0009 ATM Cell transport VCC Mode 0x000A ATM Cell transport VPC Mode 0x000B Unassigned 0x000C MPEG-TS Payload Type (MPTPW) "Data-Over-Cable Service Interface Specifications: Downstream External PHY Interface Specification CM-SP-DEPI-I01-050805", DOCSIS, August 2005 0x000D Packet Streaming Protocol (PSPPW) "Data-Over-Cable Service Interface Specifications: Downstream External PHY Interface Specification CM-SP-DEPI-I01-050805", DOCSIS, August 2005 0x000E-0x0010 Unassigned 0x0011 Structure-agnostic E1 circuit 0x0012 Structure-agnostic T1 (DS1) circuit 0x0013 Structure-agnostic E3 circuit 0x0014 Structure-agnostic T3 (DS3) circuit 0x0015 CESoPSN basic mode 0x0016 Unassigned 0x0017 CESoPSN TDM with CAS IETF Review The Circuit Status field is a 16 bit mask, with the two high order bits assigned. 9 S (Standby) bit 10 E (Local PSN-facing PW (egress) Tx Fault) bit 11 I (Local PSN-facing PW (ingress) Rx Fault) bit 12 T (Local AC (egress) Tx Fault) bit 13 R (Local AC (ingress) Rx Fault) bit 14 N (New) bit [use deprecated] 15 A (Active) bit The Default L2 Specific Sublayer contains 8 bits in the low-order portion of the header. Reserved bits may be assigned by IETF Review . 0 V (VCCV) bit 1 S (Sequence) bit 2 B (Fragmentation) bit 3 E (Fragmentation) bit 4 Reserved 5 Reserved 6 Reserved 7 Reserved Expert Review Carlos Pignataro (primary), Ignacio Goyret (secondary) The L2-Specific Sublayer Type is a 2 octet unsigned integer. Additional values may be assigned by Expert Review . 0 No L2-Specific Sublayer 1 Default L2-Specific Sublayer present 2 ATM-Specific Sublayer present 3 MPT-Specific Sublayer "Data-Over-Cable Service Interface Specifications: Downstream External PHY Interface Specification CM-SP-DEPI-I01-050805", DOCSIS, August 2005 4 PSP-Specific Sublayer "Data-Over-Cable Service Interface Specifications: Downstream External PHY Interface Specification CM-SP-DEPI-I01-050805", DOCSIS, August 2005 Expert Review Carlos Pignataro (primary), Ignacio Goyret (secondary) The Data Sequencing Level is a 2 octet unsigned integer Additional values may be assigned by Expert Review . 0 No incoming data packets require sequencing. 1 Only non-IP data packets require sequencing. 2 All incoming data packets require sequencing. IETF Review 0 V (VCCV) bit 1 S (Sequence) bit 2 B (Fragmentation) bit 3 E (Fragmentation) bit 4 T (Transport type) bit 5 G (EFCI) bit 6 C (CLP) bit 7 U (Command/Response) bit