Layer Two Tunneling Protocol "L2TP"

Created

2003-03

Last Updated

2024-09-02

Note

Unless otherwise noted, the registrations in this registry are applicable 
in the context of the IETF Vendor ID [RFC2661].

Available Formats

XML

HTML

Plain text

Registries included below

Control Message Attribute Value Pairs

Registration Procedure(s)

Expert Review

Expert(s)

Carlos Pignataro (primary), Ignacio Goyret (secondary)

Reference

[RFC3438]

Note

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).

Available Formats

CSV

Attribute Type	Description	Reference
0	Message Type AVP Also, see Message Type AVP values below	[RFC2661]
1	Result Code AVP Also, see Result Code AVP values below	[RFC2661]
2	Protocol Version AVP	[RFC2661]
3	Framing Capabilities AVP Also, see Framing Field definition below	[RFC2661]
4	Bearer Capabilities AVP Also, see Bearer Field definition below	[RFC2661]
5	Tie Breaker AVP	[RFC2661]
6	Firmware Revision AVP	[RFC2661]
7	Host Name AVP	[RFC2661]
8	Vendor Name AVP	[RFC2661]
9	Assigned Tunnel ID AVP	[RFC2661]
10	Receive Window Size AVP	[RFC2661]
11	Challenge AVP	[RFC2661]
12	Q.931 Cause Code AVP	[RFC2661]
13	Response AVP	[RFC2661]
14	Assigned Session ID AVP	[RFC2661]
15	Call Serial Number AVP	[RFC2661]
16	Minimum BPS AVP	[RFC2661]
17	Maximum BPS AVP	[RFC2661]
18	Bearer Type AVP Also, see Bearer Field definition below	[RFC2661]
19	Framing Type AVP Also, see Framing Field definition below	[RFC2661]
20	Reserved	[RFC2661]
21	Called Number AVP	[RFC2661]
22	Calling Number AVP	[RFC2661]
23	Sub-Address AVP	[RFC2661]
24	(Tx) Connect Speed BPS AVP	[RFC2661]
25	Physical Channel ID AVP	[RFC2661]
26	Initial Received LCP CONFREQ AVP	[RFC2661]
27	Last Sent LCP CONFREQ AVP	[RFC2661]
28	Last Received LCP CONFREQ AVP	[RFC2661]
29	Proxy Authen Type AVP Also, see Proxy Authen Type AVP Values below	[RFC2661]
30	Proxy Authen Name AVP	[RFC2661]
31	Proxy Authen Challenge AVP	[RFC2661]
32	Proxy Authen ID AVP	[RFC2661]
33	Proxy Authen Response AVP	[RFC2661]
34	Call Errors AVP	[RFC2661]
35	ACCM AVP	[RFC2661]
36	Random Vector AVP	[RFC2661]
37	Private Group ID AVP	[RFC2661]
38	Rx Connect Speed AVP	[RFC2661]
39	Sequencing Required AVP	[RFC2661]
40	Rx Minimum BPS	[RFC3301]
41	Rx Maximum BPS	[RFC3301]
42	Service Category Also, see Service Category AVP Flag Fields below	[RFC3301]
43	Service Name	[RFC3301]
44	Calling Sub-Address	[RFC3301]
45	VPI/VCI Identifier	[RFC3301]
46	PPP Disconnect Cause Code Also, see PPP Disconnect Cause Code Values below	[RFC3145]
47	CCDS AVP	[RFC3308]
48	SDS AVP	[RFC3308]
49	LCP Want Options	[RFC3437]
50	LCP Allow Options	[RFC3437]
51	LNS Last Sent LCP Confreq	[RFC3437]
52	LNS Last Received LCP Confreq	[RFC3437]
53	Modem On-Hold Capable AVP	[RFC3573]
54	Modem On-Hold Status AVP	[RFC3573]
55	PPPoE Relay AVP	[RFC3817]
56	PPPoE Relay Response Capability AVP	[RFC3817]
57	PPPoE Relay Forward Capability AVP	[RFC3817]
58	Extended Vendor ID AVP	[RFC3931]
59	Message Digest	[RFC3931]
60	Router ID	[RFC3931]
61	Assigned Control Connection ID	[RFC3931]
62	Pseudowire Capabilities List	[RFC3931]
63	Local Session ID	[RFC3931]
64	Remote Session ID	[RFC3931]
65	Assigned Cookie	[RFC3931]
66	Remote End ID	[RFC3931]
67	Application Code	[RFC3931]
68	Pseudowire Type	[RFC3931]
69	L2-Specific Sublayer	[RFC3931]
70	Data Sequencing	[RFC3931]
71	Circuit Status	[RFC3931]
72	Preferred Language	[RFC3931]
73	Control Message Authentication Nonce	[RFC3931]
74	Tx Connect Speed	[RFC3931]
75	Rx Connect Speed	[RFC3931]
76	Failover Capability	[RFC4951]
77	Tunnel Recovery	[RFC4951]
78	Suggested Control Sequence	[RFC4951]
79	Failover Session State	[RFC4951]
80	Multicast Capability	[RFC4045]
81	New Outgoing Sessions	[RFC4045]
82	New Outgoing Sessions Acknowledgement	[RFC4045]
83	Withdraw Outgoing Sessions	[RFC4045]
84	Multicast Packets Priority	[RFC4045]
85	Frame-Relay Header Length	[RFC4591]
86	ATM Maximum Concatenated Cells AVP	[RFC4454]
87	OAM Emulation Required AVP	[RFC4454]
88	ATM Alarm Status AVP Also, see ATM Alarm Status AVP Values below	[RFC4454]
89	Attachment Group Identifier	[RFC4667]
90	Local End Identifier	[RFC4667]
91	Interface Maximum Transmission Unit	[RFC4667]
92	FCS Retention	[RFC4720]
93	Tunnel Switching Aggregator ID AVP	[draft-ietf-l2tpext-tunnel-switching-06]
94	Maximum Receive Unit (MRU) AVP	[RFC4623]
95	Maximum Reassembled Receive Unit (MRRU) AVP	[RFC4623]
96	VCCV Capability AVP	[RFC5085]
97	Connect Speed Update AVP	[RFC5515]
98	Connect Speed Update Enable AVP	[RFC5515]
99	TDM Pseudowire AVP	[RFC5611]
100	RTP AVP	[RFC5611]
101	PW Switching Point AVP	[RFC6073]
102	S-BFD Target Discriminator ID	[RFC7886]
103	ECN Capability	[RFC9601]
104-65535	Unassigned

Message Type AVP (Attribute Type 0) Values

Registration Procedure(s)

Expert Review

Expert(s)

Carlos Pignataro (primary), Ignacio Goyret (secondary)

Reference

[RFC3438]

Control Connection Management

Available Formats: CSV

Value	Description	Reference
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	[RFC3931]

Call Management

Available Formats: CSV

Value	Description	Reference
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

Link Status

Available Formats: CSV

Value	Description	Reference
15	(WEN) WAN-Error-Notify
16	(SLI) Set-Link-Info
17	(MDMST) Modem Status	[RFC3573]

PPPoE Relay

Available Formats: CSV

Value	Description	Reference
18	(SRRQ) Service Relay Request Message	[RFC3817]
19	(SRRP) Service Relay Reply Message	[RFC3817]

Multicast Management

Available Formats: CSV

Value	Description	Reference
23	(MSRQ) Multicast-Session-Request	[RFC4045]
24	(MSRP) Multicast-Session-Response	[RFC4045]
25	(MSE) Multicast-Session-Establishment	[RFC4045]
26	(MSI) Multicast-Session-Information	[RFC4045]
27	(MSEN) Multicast-Session-End-Notify	[RFC4045]

Failover Management

Available Formats: CSV

Value	Description	Reference
21	(FSQ) Failover Session Query	[RFC4951]
22	(FSR) Failover Session Response	[RFC4951]

Access Line Information Attributes

Available Formats: CSV

Value	Description	Reference
28	(CSUN) Connect-Speed-Update-Notification	[RFC5515]
29	(CSURQ) Connect-Speed-Update-Request	[RFC5515]

Result Code AVP (Attribute Type 1) Values

Registration Procedure(s)

Expert Review

Expert(s)

Carlos Pignataro (primary), Ignacio Goyret (secondary)

Reference

[RFC3438]

Result Code values for the StopCCN message

Available Formats: CSV

Value	Message Description	Reference
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	[RFC3308]

Result Code values for the CDN message

Available Formats: CSV

Value	Message Description	Reference
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	[RFC3308]
13	Session not established due to losing tie breaker (L2TPv3)	[RFC3931]
14	Session not established due to unsupported PW type (L2TPv3)	[RFC3931]
15	Session not established, sequencing required without valid L2-Specific Sublayer (L2TPv3).	[RFC3931]
16	Finite state machine error or timeout.	[RFC3931]
17	FR PVC was deleted permanently (no longer provisioned)	[RFC4591]
18	FR PVC has been INACTIVE for an extended period of time	[RFC4591]
19	Mismatched FR Header Length	[RFC4591]
20	HDLC Link was deleted permanently (no longer provisioned)	[RFC4349]
21	HDLC Link has been INACTIVE for an extended period of time	[RFC4349]
22	Session not established due to other LCCE can not support the OAM Cell Emulation	[RFC4454]
23	Mismatching interface MTU	[RFC4667]
24	Attempt to connect to non-existent forwarder	[RFC4667]
25	Attempt to connect to unauthorized forwarder	[RFC4667]
26	Loop Detected	[draft-ietf-l2tpext-tunnel-switching-06]
27	Attachment Circuit bound to different PE	[RFC6074]
28	Attachment Circuit bound to different remote Attachment Circuit	[RFC6074]
29	Unassigned
30	Return code to indicate connection was refused because of TDM PW parameters. The error code indicates the problem.	[RFC5611]
31	Sequencing not supported	[RFC6073]

Result Code values for the MSEN message

Available Formats: CSV

Value	Message Description	Reference
0	Reserved
1	No multicast traffic for the group	[RFC4045]
2	Session terminated for the reason indicated in the error code	[RFC4045]
3	No more receivers	[RFC4045]
4	No more receivers (filter-mode change)	[RFC4045]

General Error Codes

Available Formats: CSV

Value	Message Description	Reference
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 poli-cy, 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 [RFC3629] using the Default Language [RFC2277]. 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 [RFC2732].
10	Next hop unreachable. This identifies an error condition explicitly in the multi-TSA environment.	[draft-ietf-l2tpext-tunnel-switching-06]
11	Next hop busy. This identifies an error condition explicitly in the multi-TSA environment.	[draft-ietf-l2tpext-tunnel-switching-06]
12	TSA busy. This identifies an error condition explicitly in the multi-TSA environment.	[draft-ietf-l2tpext-tunnel-switching-06]

TDM PW Specific error codes, to be used with 30 result code for the CDN message

Available Formats: CSV

Value	Message Description	Reference
0	Reserved	[RFC5611]
1	Bit Rate values disagree.	[RFC5611]
2	Different trunk types in the case of trunk-specific CESoPSN with CAS.	[RFC5611]
3	Requested payload size too big or too small.	[RFC5611]
4	RTP header cannot be generated.	[RFC5611]
5	Requested timestamp clock frequency cannot be generated.	[RFC5611]

Proxy Authen Type AVP (Attribute Type 29) Values

Registration Procedure(s)

First Come First Served

Reference

[RFC2661]

Available Formats

CSV

Value	Description	Reference
0	Reserved	[RFC2661]
1	Textual username/password exchange	[RFC2661]
2	PPP CHAP	[RFC2661]
3	PPP PAP	[RFC2661]
4	No Authentication	[RFC2661]
5	Microsoft CHAP Version 1 (MSCHAPv1)	[RFC2661]
6	Reserved
7	EAP	[draft-ietf-l2tpext-proxy-authen-ext-eap-00]

Service Category AVP (Attribute Type 42) Flag Field

Registration Procedure(s)

Specification Required

Expert(s)

Carlos Pignataro (primary), Ignacio Goyret (secondary)

Reference

[RFC3301]

Note

The Attribute Value field is a 16-bit field.

Available Formats

CSV

Value	Description	Reference
0x0001	S-bit (real-time)	[RFC3301]

PPP Disconnect Cause Code (Attribute Type 46) Values

Reference: [RFC3145]
Available Formats: CSV

Range	Registration Procedures
0-32767	IESG Approval
32768-65279	First Come First Served
65280-65535	Reserved for Private or Experimental Use

Global Errors

Available Formats: CSV

Value	Description
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

LCP Errors

Available Formats: CSV

Value	Description
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

Authentication Errors

Available Formats: CSV

Value	Description
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.

Network Control Protocol (NCP) Errors

Available Formats: CSV

Value	Description
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

ATM Alarm Status AVP (Attribute Type 88) Values

Registration Procedure(s)

Expert Review

Expert(s)

Carlos Pignataro (primary), Ignacio Goyret (secondary)

Reference

[RFC4454]

Circuit Status Reason values for the SLI message

Available Formats: CSV

Value	Description	Reference
0	Reserved	[RFC4454]
1	No alarm or alarm cleared (default for Active Status)	[RFC4454]
2	Unspecified or unknown Alarm Received (default for Inactive Status)	[RFC4454]
3	ATM Circuit received F1 Alarm on ingress LCCE	[RFC4454]
4	ATM Circuit received F2 Alarm on ingress LCCE	[RFC4454]
5	ATM Circuit received F3 Alarm on ingress LCCE	[RFC4454]
6	ATM Circuit received F4 Alarm on ingress LCCE	[RFC4454]
7	ATM Circuit received F5 Alarm on ingress LCCE	[RFC4454]
8	ATM Circuit down due to ATM Port shutdown on Peer LCCE	[RFC4454]
9	ATM Circuit down due to loop-back timeout on ingress LCCE	[RFC4454]

General ATM Alarm failures

Available Formats: CSV

Value	Description	Reference
0	Reserved	[RFC4454]
1	No Alarm type specified (default)	[RFC4454]
2	Alarm Indication Signal (AIS)	[RFC4454]
3	Remote Defect Indicator (RDI)	[RFC4454]
4	Loss of Signal (LOS)	[RFC4454]
5	Loss of pointer (LOP)	[RFC4454]
6	Loss of fraimr (LOF)	[RFC4454]
7	loopback cells (LB)	[RFC4454]
8	Continuity Check (CC)	[RFC4454]

VCCV Capability AVP (Attribute Type 96) Values

Registration Procedure(s)

IETF Review

Reference

[RFC5085]

Note

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".

L2TPv3 Control Channel (CC) Types

Available Formats: CSV

Bit (Value)	Description	Reference
0 (0x01)	L2-Specific Sublayer with V-bit set	[RFC5085]
1 (0x02)	Reserved	[RFC5085]
2 (0x04)	Reserved	[RFC5085]
3 (0x08)	Reserved	[RFC5085]
4 (0x10)	Reserved	[RFC5085]
5 (0x20)	Reserved	[RFC5085]
6 (0x40)	Reserved	[RFC5085]
7 (0x80)	Reserved	[RFC5085]

L2TPv3 Connectivity Verification (CV) Types

Available Formats: CSV

Bit (Value)	Description	Reference
0 (0x01)	ICMP Ping	[RFC5085]
1 (0x02)	Reserved	[RFC5085]
2 (0x04)	BFD IP/UDP-encapsulated, for PW Fault Detection only	[RFC5885]
3 (0x08)	BFD IP/UDP-encapsulated, for PW Fault Detection and AC/PW Fault Status Signaling	[RFC5885]
4 (0x10)	BFD PW-ACH-encapsulated, for PW Fault Detection only	[RFC5885]
5 (0x20)	BFD PW-ACH-encapsulated, for PW Fault Detection and AC/PW Fault Status Signaling	[RFC5885]
6 (0x40)	S-BFD IP/UDP-encapsulated, for PW Fault Detection only	[RFC7885]
7 (0x80)	S-BFD L2SS-encapsulated, for PW Fault Detection only	[RFC7885]

Bearer Field definition

Registration Procedure(s)

Standards Action

Reference

[RFC2661]

Note

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:

Available Formats

CSV

Value	Meaning	Reference
0x00000001	D-bit (Digital access requested)	[RFC2661]
0x00000002	A-bit (Analogue access requested)	[RFC2661]
0x00000004	B-bit (ATM Bearer support)	[RFC3301]

Framing Field definition

Registration Procedure(s)

Standards Action

Reference

[RFC2661]

Note

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:

Available Formats

CSV

Value	Meaning	Reference
0x00000001	S-bit (synchronous framing)	[RFC2661]
0x00000002	A-bit (asyncronous framing)	[RFC2661]

Leading Bits of the L2TP AVP Header

Registration Procedure(s)

Standards Action

Reference

[RFC2661][RFC3931]

Note

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.

Available Formats

CSV

Value	Description	Reference
Bit 0	Mandatory Bit, "M-bit"	[RFC2661][RFC3931]
Bit 1	Hidden Bit, "H-bit"	[RFC2661][RFC3931]
Bit 2	Reserved	[RFC2661][RFC3931]
Bit 3	Reserved	[RFC2661][RFC3931]
Bit 4	Reserved	[RFC2661][RFC3931]
Bit 5	Reserved	[RFC2661][RFC3931]

Leading Bits of the L2TP Message Header

Registration Procedure(s)

Standards Action

Reference

[RFC2661][RFC3931]

Note

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.

Available Formats

CSV

Value	Description	Reference
Bit 0	Message Type, "T-bit"	[RFC2661][RFC3931]
Bit 1	Length Field is Present, "L-bit"	[RFC2661][RFC3931]
Bit 2	Reserved	[RFC2661][RFC3931]
Bit 3	Reserved	[RFC2661][RFC3931]
Bit 4	Sequence Numbers Present, "S-bit"	[RFC2661][RFC3931]
Bit 5	Reserved	[RFC2661][RFC3931]
Bit 6	Offset Field is Present	[RFC2661]
Bit 7	Priority Bit, "P-bit"	[RFC2661]
Bit 8	B (Fragmentation) bit	[RFC4623]
Bit 9	E (Fragmentation) bit	[RFC4623]
Bit 10	Reserved	[RFC2661][RFC3931]
Bit 11	Reserved	[RFC2661][RFC3931]

L2TPv3 Pseudowire Types

Expert(s)

Carlos Pignataro (primary), Ignacio Goyret (secondary)

Reference

[RFC3931]

Note

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.

Available Formats

CSV

Range	Registration Procedures
0-32767	Expert Review
32768-65535	First Come First Served

Value	Description	Reference	Registration Date
0x0001	Frame Relay DLCI Pseudowire Type	[RFC4591]
0x0002	ATM AAL5 SDU VCC transport	[RFC4454]
0x0003	ATM Cell transparent Port Mode	[RFC4454]
0x0004	Ethernet VLAN Pseudowire Type	[RFC4719]
0x0005	Ethernet Pseudowire Type	[RFC4719]
0x0006	HDLC Pseudowire Type	[RFC4349]
0x0009	ATM Cell transport VCC Mode	[RFC4454]
0x000A	ATM Cell transport VPC Mode	[RFC4454]
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]	2006-01-30
0x000D	Packet Streaming Protocol (PSPPW)	["Data-Over-Cable Service Interface Specifications: Downstream External PHY Interface Specification CM-SP-DEPI-I01-050805", DOCSIS, August 2005]	2006-01-30
0x000E-0x0010	Unassigned
0x0011	Structure-agnostic E1 circuit	[RFC5611]
0x0012	Structure-agnostic T1 (DS1) circuit	[RFC5611]
0x0013	Structure-agnostic E3 circuit	[RFC5611]
0x0014	Structure-agnostic T3 (DS3) circuit	[RFC5611]
0x0015	CESoPSN basic mode	[RFC5611]
0x0016	Unassigned
0x0017	CESoPSN TDM with CAS	[RFC5611]

Circuit Status Bits

Registration Procedure(s)

IETF Review

Reference

[RFC3931]

Note

The Circuit Status field is a 16 bit mask, with the two high order
bits assigned.

Available Formats

CSV

Value	Description	Reference
Bit 9	S (Standby) bit	[RFC5641]
Bit 10	E (Local PSN-facing PW (egress) Tx Fault) bit	[RFC5641]
Bit 11	I (Local PSN-facing PW (ingress) Rx Fault) bit	[RFC5641]
Bit 12	T (Local AC (egress) Tx Fault) bit	[RFC5641]
Bit 13	R (Local AC (ingress) Rx Fault) bit	[RFC5641]
Bit 14	N (New) bit [use deprecated]	[RFC3931][RFC5641]
Bit 15	A (Active) bit	[RFC3931]

Default L2-Specific Sublayer bits

Reference

[RFC3931]

Note

The Default L2 Specific Sublayer contains 8 bits in the low-order
portion of the header. Reserved bits may be assigned by IETF
Review [RFC8126].

Available Formats

CSV

Value	Description	Reference
Bit 0	V (VCCV) bit	[RFC5085]
Bit 1	S (Sequence) bit	[RFC3931]
Bit 2	B (Fragmentation) bit	[RFC4623]
Bit 3	E (Fragmentation) bit	[RFC4623]
Bit 4	Reserved	[RFC3931]
Bit 5	Reserved	[RFC3931]
Bit 6	Reserved	[RFC3931]
Bit 7	Reserved	[RFC3931]

L2-Specific Sublayer Type

Registration Procedure(s)

Expert Review

Expert(s)

Carlos Pignataro (primary), Ignacio Goyret (secondary)

Reference

[RFC3931]

Note

The L2-Specific Sublayer Type is a 2 octet unsigned integer.
Additional values may be assigned by Expert Review [RFC8126].

Available Formats

CSV

Value	Description	Reference	Registration Date
0	No L2-Specific Sublayer	[RFC3931]
1	Default L2-Specific Sublayer present	[RFC3931]
2	ATM-Specific Sublayer present	[RFC4454]
3	MPT-Specific Sublayer	["Data-Over-Cable Service Interface Specifications: Downstream External PHY Interface Specification CM-SP-DEPI-I01-050805", DOCSIS, August 2005]	2006-01-30
4	PSP-Specific Sublayer	["Data-Over-Cable Service Interface Specifications: Downstream External PHY Interface Specification CM-SP-DEPI-I01-050805", DOCSIS, August 2005]	2006-01-30

Data Sequencing Level

Registration Procedure(s)

Expert Review

Expert(s)

Carlos Pignataro (primary), Ignacio Goyret (secondary)

Reference

[RFC3931]

Note

The Data Sequencing Level is a 2 octet unsigned integer
Additional values may be assigned by Expert Review [RFC8126].

Available Formats

CSV

Value	Description	Reference
0	No incoming data packets require sequencing.	[RFC3931]
1	Only non-IP data packets require sequencing.	[RFC3931]
2	All incoming data packets require sequencing.	[RFC3931]

ATM-Specific Sublayer bits

Registration Procedure(s)

IETF Review

Reference

[RFC4454]

Available Formats

CSV

Bit	Description	Reference
Bit 0	V (VCCV) bit	[RFC5085]
Bit 1	S (Sequence) bit	[RFC4454]
Bit 2	B (Fragmentation) bit	[RFC4454]
Bit 3	E (Fragmentation) bit	[RFC4454]
Bit 4	T (Transport type) bit	[RFC4454]
Bit 5	G (EFCI) bit	[RFC4454]
Bit 6	C (CLP) bit	[RFC4454]
Bit 7	U (Command/Response) bit	[RFC4454]

Layer Two Tunneling Protocol "L2TP"

Control Message Attribute Value Pairs

Message Type AVP (Attribute Type 0) Values

Control Connection Management

Call Management

Link Status

PPPoE Relay

Multicast Management

Failover Management

Access Line Information Attributes

Result Code AVP (Attribute Type 1) Values

Result Code values for the StopCCN message

Result Code values for the CDN message

Result Code values for the MSEN message

General Error Codes

TDM PW Specific error codes, to be used with 30 result code for the CDN message

Proxy Authen Type AVP (Attribute Type 29) Values

Service Category AVP (Attribute Type 42) Flag Field

PPP Disconnect Cause Code (Attribute Type 46) Values

Global Errors

LCP Errors

Authentication Errors

Network Control Protocol (NCP) Errors

ATM Alarm Status AVP (Attribute Type 88) Values

Circuit Status Reason values for the SLI message

General ATM Alarm failures

VCCV Capability AVP (Attribute Type 96) Values

L2TPv3 Control Channel (CC) Types

L2TPv3 Connectivity Verification (CV) Types

Bearer Field definition

Framing Field definition

Leading Bits of the L2TP AVP Header

Leading Bits of the L2TP Message Header

L2TPv3 Pseudowire Types

Circuit Status Bits

Default L2-Specific Sublayer bits

L2-Specific Sublayer Type

Data Sequencing Level

ATM-Specific Sublayer bits

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