rfc3301.txt

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   in the latter case.

4.2 Authorization

   Because of the flexibility of establishing ATM connections with
   varying parameters, some authorization may be required prior to
   accepting the establishment of a switched ATM connection from the
   user with certain ATM traffic parameters.  This authorization may be
   performed against the ATM specific authentication information (e.g.
   calling line id), or may be performed after partial authentication of
   the user at the PPP level.  Non authorized access requests result in
   connection release.

5. New and extended AVPs

5.1 New AVP Summary

   The following table lists the extra AVPs that are defined within this
   document.  The "attr" column indicates the integer value assigned to
   this attribute.  Note that the attribute value is relative compared
   to the vendor ID.  The "M" column indicates the setting of the
   "Mandatory" bit of the AVP header for each attribute.  The "LEN"
   column indicates the size of the AVP including the AVP header.  A "+"
   in this column indicates that the length varies depending upon the
   length of the actual contents of the value field.

   The usage list for each entry indicates the message types that
   utilize each AVP.  An abbreviation shown in mixed or upper case
   letters indicates that the corresponding AVP MUST be present in this
   message type.  All lower case indicates that the AVP MAY optionally
   appear in this message type.  Some AVPs MAY be present only when a
   corresponding optional AVP or specific setting within the AVP is
   present, these AVPs are shown in lower case as well.




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RFC 3301          L2TP: ATM access network extensions          June 2002


   Attr    M       Len     Attribute Name (usage)

   40      0       10      Rx Minimum BPS (ocrq)
      32-bit integer indicating the lowest acceptable line speed for the
      call in the receive direction.  Rx indicates the user to LAC
      direction.
   41      0       10      Rx Maximum BPS (ocrq)
      32-bit integer indicating the highest acceptable line speed for
      call in the receive direction.  Rx indicates the user to LAC
      direction.
   42      0       8       Service Category (ocrq, icrq)
      The Service Category indicates the service expected for the call,
      e.g., real time or non-real time.
   43      0       6+      Service Name (ocrq, icrq)
      The Service Name indicates the service name linked to a
      preestablished PVC.
   44      0       26      Calling Sub-Address(icrq)
      20 octet binary encoded NSAP subaddress indicating the Calling
      Party Sub-Address.
   45      0       10      VPI/VCI identifier (icrq, ocrp)
      10 octet binary encoded identification of VPI/VCI values used for
      incoming calls.

5.2 New AVP definition

   The following lists the new AVPs defined within this document, and
   describes the expected behaviour when this AVP would be present
   within a message.

   Rx Minimum BPS (OCRQ)

         The Rx Minimum BPS, Attribute Type 40, encodes the lowest
         acceptable line speed for this call in the receive direction,
         for these cases where asymmetric transmission is required.

         The Attribute Value field for this AVP has the following
         format:

   0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                       Rx Minimum BPS                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

         The Rx Minimum BPS is a 32 bit value indicating the speed in
         bits per second.





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         This AVP MAY be included within the OCRQ, and SHOULD only be
         included when the LAC indicated broadband bearer support in the
         bearer capabilities AVP during tunnel establishment.

         This AVP may be hidden (the H-bit may be set to 0 or 1).  The
         M- bit for this AVP must be set to 0.  The Length (before
         hiding) of this AVP is 10.

   Rx Maximum BPS

         The Rx Maximum BPS, Attribute Type 41, encodes the highest
         acceptable line speed for this call in the receive direction,
         for these cases where asymmetric transmission is required.

         The Attribute Value field for this AVP has the following
         format:

   0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        Rx Maximum BPS                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

         The Rx Maximum BPS is a 32 bit value indicating the speed in
         bits per second.

         This AVP MAY be included within the OCRQ, and SHOULD only be
         included when the LAC indicated broadband bearer support in the
         bearer capabilities AVP during tunnel establishment.

         This AVP may be hidden (the H-bit may be set to 0 or 1).  The
         M- bit for this AVP must be set to 0.  The Length (before
         hiding) of this AVP is 10.

   Service Category

         The Service Category AVP, Attribute type 42, indicates optional
         extra information on the Quality of Service expected for the
         call establishment on the broadband bearer medium.

         The Attribute Value field for this AVP has the following
         format:

   0                   1
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Resvd for future QoS ind.   |S|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



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         The Attribute Value field is a 16-bit mask, with one bit
         defined.  The S bit indicates either non real time (S bit set
         to 0) or real time (S bit set to 1) service requirement.  The
         other bit fields are reserved for future use.

         The Service Category AVP MAY be present in OCRQ and ICRQ
         messages, and SHOULD only be included when the LAC indicated
         broadband bearer support in the bearer capabilities AVP during
         tunnel establishment.

         This AVP may be hidden (the H-bit may be set to 0 or 1).  The
         M- bit for this AVP must be set to 0.  The Length (before
         hiding) of this AVP is 8.

   Service Name

         The Service Name AVP, Attribute Type 43, provides the peer with
         an textual name for referring to an ATM VC connection.

         The Attribute Value field for this AVP has the following
         format:

   0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Service Name (arbitrary number of octets) ....
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

         The Service Name is of arbitrary length, but must be at least 1
         octet.  The Service Name is UTF-8 encoded. [10646]

         The Service Name should be unique at least to the LNS/LAC
         combination.

         The Service Name AVP MAY only be provided when the Called
         Number field is encoded as all zeros in OCRQ.  The Service Name
         AVP MAY be present in OCRQ and ICRQ messages, and SHOULD only
         be included when the LAC indicated broadband bearer support in
         the bearer capabilities AVP during tunnel establishment.

         This AVP may be hidden (the H-bit may be set to 0 or 1).  The
         M- bit for this AVP must be set to 0.  The length of this
         attribute is arbitrary, however at least 7.

   Calling Sub-Address (ICRQ)

         The Calling Sub-Address AVP, Attribute Type 44, encodes
         additional Calling Party subaddress information.



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         The Attribute Value field for this AVP has the following
         format:

   0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                              NSAP                             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                         NSAP (cont'd)                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                         NSAP (cont'd)                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                         NSAP (cont'd)                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                         NSAP (cont'd)                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

         The Calling Sub-Address AVP MUST be encoded as a 20 octet
         binary encoded NSAP address when the B bit is set in the Bearer
         Type AVP.  The NSAP binary encoded address provides a broader
         range of address encapsulation methods than an ASCII field.
         The structure of the NSAP address (e.g., E.164, ICD, DCC) is
         defined in [AESA].

         The Calling Sub-Address number AVP MAY be present in ICRQ, and
         SHOULD only be available if the Calling Party number is also
         within the message.

         This AVP may be hidden (the H-bit may be 0 or 1).  The M-bit
         for this AVP MUST be set to 0.  The Length (before hiding) of
         this AVP is 26.

   VPI/VCI identifier(icrq, ocrp)

         The VPI/VCI identifier, Attribute Type 45, encodes the VPI/VCI
         value used at the ATM interface at the LAC.

         The Attribute Value field for this AVP has the following
         format:

   0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |resvd  |           VPI         |              VCI              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

         The VPI/VCI identifier is a 32 bit value encoding the VPI(12
         bits) and VCI (16 bits) value.



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         This AVP MAY be included within the ICRQ and OCRP, and SHOULD
         only be included when the LAC indicated broadband bearer
         support in the bearer capabilities AVP during tunnel
         establishment.

         This AVP may be hidden (the H-bit may be set to 0 or 1).  The
         M- bit for this AVP must be set to 0.  The Length (before
         hiding) of this AVP is 10.

5.3 Changed AVP Definition

   The following AVPs see their contents changed relative to [RFC2661]
   in order to support the procedures described in this document.

   Bearer Capabilities

   0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Resvd for future bearer capability definitions         |B|A|D|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

         The bearer Capabilities AVP within a SCCRQ or SCCRP indicates
         the bearer capabilities that the sender of this message can
         provide for outgoing calls.  This document extends the existing
         AVP with the B bit.  If bit B is set, broadband access is
         supported (ATM).

         Attempts to establish an outgoing call with the bearer type set
         to B, while the bearer capability did not indicate this
         capability will result in the call being rejected with Result
         Code 5 'Call failed due to lack of appropriate facilities being
         available (permanent condition)'.

         In these cases where the LAC only supports the B bit, and the
         LNS would not recognize the B bit, no outgoing calls are
         possible.  Note that when the LAC only has ATM based devices,
         it may still opt for seamless fall back to digital bearer
         types.

         This specification assumes a non-compliant LNS to categorize a
         Bearer Capabilities AVP where the B bit is set as unrecognized
         AVP, upon which the tunnel establishment will fail.  This is to
         be indicated by a Result Code '2-General error - Error Code
         indicates the problem', Error Code '3- Reserved field was non-
         zero'.





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   (Tx) Minimum BPS

         The (Tx) Minimum BPS AVP encodes the lowest acceptable line
         speed for this call in the transmit direction.  The (Tx)
         Minimum BPS AVP MAY be used in OCRQ.  If the Rx Minimum BPS
         AVP, as defined within this document, is not available in the
         message, then symmetric transmission is implied, with both
         minimum receive and transmit bit-rates equal to Minimum BPS.

   (Tx) Maximum BPS

         (Tx) Maximum BPS AVP encodes the highest acceptable line speed
         for this call in the transmit direction.  The (Tx) Maximum BPS
         AVP MAY be used in OCRQ.  If the Rx Maximum BPS AVP, as defined
         within this document, is not available in the message, then
         symmetric transmission is implied, with both maximum receive
         and transmit bitrates equal to Maximum BPS.

   Bearer Type

   0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       Resvd for future bearer types definitions         |B|A|D|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

         The bearer type AVP encodes the bearer type for the requested
         call.  This document extends the bearer types with an
         indication of ATM bearer support (B-bit).  If bit B is set,
         broadband access is requested (ATM).  If bit A is set, analogue
         access is requested.  If bit D is set, Digital access is
         requested.

         Note that in the OCRQ all 3 bits (B,A,D) may be set indicating