Layer Two Tunneling Protocol "L2TP" - RFC 2661 Control Message Attribute Value Pairs 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). The following sections contain a list of all L2TP AVPs defined in RFC 2661. Attribute Type Description Reference --------- ------------------ --------- 0 Message Type AVP [RFC2661] 1 Result Code AVP [RFC2661] 2 Protocol Version AVP [RFC2661] 3 Framing Capabilities AVP [RFC2661] 4 Bearer Capabilities AVP [RFC2661] 5 Tie Breaker AVP [RFC2661] 6 Firmward 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 [RFC2661] 19 Framing Type AVP [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 [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] -Message Type AVP (Attribute Type 0) Values Control Connection Management 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 Call Management 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 Error Reporting 15 (WEN) WAN-Error-Notify PPP Session Control 16 (SLI) Set-Link-Info -Result Code AVP (Attribute Type 1) Values Defined Result Code values for the StopCCN message are: 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 Defined Result Code values for the CDN message are: 0 - Reserved 1 - Call disconnected due to loss of carrier 2 - Call disconnected for the reason indicated in error code 3 - Call disconnected for administrative reasons 4 - Call failed due to lack of appropriate facilities being available (temporary condition) 5 - Call 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 General Error Codes 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. -Proxy Authen Type AVP (Attribute Type 29) Values 0 - Reserved 1 - Textual username/password exchange 2 - PPP CHAP 3 - PPP PAP 4 - No Authentication 5 - Microsoft CHAP Version 1 (MSCHAPv1) References ---------- [RFC2661] Townsley, W., et al., "Layer Two Tunneling Protocol "L2TP"", RFC 2661, August 1999. People ------ (created 03/00) []