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 | 
Layer Two Tunneling Protocol "L2TP" -  [RFC2661]
(last updated 2003-07-09)
For registration procedures, please see [RFC3438].
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]
            Also, see Message Type AVP values below
        1   Result Code AVP                                 [RFC2661]
            Also, see Result Code AVP values below
        2   Protocol Version AVP                            [RFC2661]
        3   Framing Capabilities AVP                        [RFC2661]
            Also, see Framing Field definition below
        4   Bearer Capabilities AVP                         [RFC2661] 
            Also, see Bearer Field definition below
        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]
            Also, see Bearer Field definition below
       19   Framing Type AVP                                [RFC2661]
            Also, see Framing Field definition below
       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]
            Also, see Proxy Authen Type AVP Values below
       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                                [RFC3301]
            Also, see Service Category AVP Flag Fields
            below
       43   Service Name                                    [RFC3301]
       44   Calling Sub-Address                             [RFC3301]
       45   VPI/VCI Identifier                              [RFC3301]
       46   PPP Disconnect Cause Code                       [RFC3145]
            Also, see PPP Disconnect Cause Code Values 
            below
       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                       [RFC-ietf-l2tpext-v92-moh-05.txt]
       54   Modem On-Hold Status AVP                        [RFC-ietf-l2tpext-v92-moh-05.txt]
        
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
   Link Status
      15 (WEN)      WAN-Error-Notify             
      16 (SLI)      Set-Link-Info
      17 (MDMST)    Modem Status                 [RFC-ietf-l2tpext-v92-moh-05.txt]
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
         8 - Control connection due to mismatching CCDS value     [RFC3308] 
  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
         12 - Disconnecting call due to mismatching SDS value     [RFC3308] 
  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)
Service Category AVP (Attribute Type 42) Flag Field
----------------------------------------------------
The Attribute Value field is a 16-bit field, with current
defined bits:
Value	 Description                            Reference
------   ------------------------------------	---------
0x0001	 S-bit (real-time)                      [RFC3301]
PPP Disconnect Cause Code (Attribute Type 46) Values
----------------------------------------------------
  Global Errors  
  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
  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
  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
  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 (by the IANA)
  65280-65535 Private or Experimental Use
Bearer Field definition:
-----------------------
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:
Value       Meaning                             Reference
0x00000001	D-bit (Digital access requested)    [RFC2661]
0x00000002	A-bit (Analogue access requested)   [RFC2661]
0x00000004	B-bit (ATM Bearer support)          [RFCXXXX]
Framing Field definition:
------------------------
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:
Value       Meaning                         Reference
0x00000001	S-bit (synchronous framing)     [RFC2661]
0x00000002	A-bit (asyncronous framing)     [RFC2661]
References
----------
[RFC2661] Townsley, W., et al., "Layer Two Tunneling Protocol "L2TP"",
          RFC 2661, August 1999.
	
[RFC3145] R. Verma, M. Verma, and J. Carlson, "L2TP Disconnect 
          Cause Information", RFC 3145, July 2001. 
[RFC3301] Y. T'Joens, P. Crivellari, and B. Sales, "Layer Two 
          Tunnelling Protocol : ATM access network extensions", 
          RFC 3301, June 2002.
[RFC3308] P. Calhoun, W. Luo, D. McPherson, and K. Peirce, "L2TP 
          Differentiated Services Extension", RFC 3308, November 2002.
[RFC3437] W. Palter and W. M. Townsley, "Layer-Two Tunneling Protocol 
          (L2TP) Extensions for PPP Link Control Protocol (LCP) 
          Negotiation, RFC 3437, November 2002.
[RFC3438] W. M. Townsley, "Layer Two Tunneling Protocol (L2TP) Internet
[BCP68]   Assigned Numbers Authority (IANA) Considerations Update",
          RFC 3438, BCP 68, November 2002.
[RFC-ietf-l2tpext-v92-moh-05.txt]
          I. Goyret, "Signalling of Modem-On-Hold status in Layer 2 
          Tunneling Protocol (L2TP)", RFC XXXX, Month Year.
 
(created 2000-03) 
[]	
 |