Network Working Group                                            G. Zorn
Internet-Draft                                     Microsoft Corporation
Category: Informational                                    February 1998
<draft-ietf-radius-ms-ba-attr-01.txt>

    RADIUS Attributes for Multilink PPP Bandwidth Allocation Control


1.  Status of this Memo

This  document  is an Internet-Draft.  Internet-Drafts are working docu-
ments of the Internet Engineering Task Force (IETF), its areas, and  its
working groups.  Note that other groups may also distribute working doc-
uments as Internet-Drafts.

Internet-Drafts are draft documents valid for a maximum  of  six  months
and  may  be  updated,  replaced, or obsoleted by other documents at any
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or to cite them other than as ``work in progress''.

To  learn  the  current  status  of any Internet-Draft, please check the
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This memo provides information for the Internet  community.   This  memo
does  not specify an Internet standard of any kind.  The distribution of
this memo  is  unlimited.   It  is  filed  as  <draft-ietf-radius-ms-ba-
attr-01.txt>  and  expires August 28, 1998.  Please send comments to the
RADIUS Working Group mailing list (ietf-radius@livingston.com) or to the
author (glennz@microsoft.com).


2.  Abstract

This  document  describes  a  set  of  vendor-specific RADIUS attributes
designed to support the dynamic control of bandwidth allocation in  mul-
tilink  PPP [1].  Attributes are defined that specify whether use of the
PPP Bandwidth Allocation Protocol [2] is allowed or required on incoming
calls,  the  level  of  line  capacity (expressed as a percentage) below
which utilization must fall before a link is eligible to be dropped, and
the length of time (in seconds) that a link must be underutilized before
it is dropped.








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3.  Specification of Requirements

In this document, the key words "MAY", "MUST,  "MUST  NOT",  "optional",
"recommended",  "SHOULD",  and  "SHOULD  NOT"  are  to be interpreted as
described in [3].


4.  Attributes

The following sections describe sub-attributes which may be  transmitted
in one or more RADIUS attributes of type Vendor-Specific [4].  More than
one  sub-attribute  MAY  be  transmitted  in  a  single  Vendor-Specific
Attribute;  if  this  is  done, the sub-attributes SHOULD be packed as a
sequence of Vendor-Type/Vendor-Length/Value triples following the inital
Type,  Length and Vendor-ID fields.  The Length field of the Vendor-Spe-
cific Attribute MUST be set equal to the sum of the Vendor-Length fields
of  the  sub-attributes contained in the Vendor-Specific Attribute, plus
six.  The Vendor-ID field of the Vendor-Specific  Attribute(s)  MUST  be
set to decimal 311 (Microsoft).


4.1.  MS-BAP-Usage

   Description

      This Attribute describes whether the use of BAP is allowed, disal-
      lowed or required on new multilink  calls.   It  MAY  be  used  in
      Access-Accept packets.

   A  summary  of the MS-BAP-Usage Attribute format is shown below.  The
   fields are transmitted from left to right.

   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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Vendor-Type | Vendor-Length |            Value
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
             Value (cont)        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Vendor-Type
      13 for MS-BAP-Usage.

   Vendor-Length
      6

   Value
      The Value field is four octets.



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         0      BAP usage not allowed
         1      BAP usage allowed
         2      BAP usage required


4.2.  MS-Link-Utilization-Threshold

   Description

      This Attribute represents the percentage  of  available  bandwidth
      utilization below which the link must fall before the link is eli-
      gible for termination.  Permissible values  for  the  MS-Link-Uti-
      lization-Threshold  Attribute  are  in the range 1-100, inclusive.
      It is only used in Access-Accept packets.

   A summary of the MS-Link-Utilization-Threshold  Attribute  format  is
   shown below.  The fields are transmitted from left to right.

   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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Vendor-Type  | Vendor-Length |            Value
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
              Value (cont)         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Vendor-Type
      14 for MS-Link-Utilization-Threshold

   Vendor-Length
      6

   Value
      The  Value  field is four octets in length and represents the per-
      centage of available bandwidth utilization below  which  the  link
      must  fall before the link is eligible for termination.  Permissi-
      ble values are in the range 1-100, inclusive.


4.3.  MS-Link-Drop-Time-Limit

   Description

      The MS-Link-Drop-Time-Limit Attribute indicates the length of time
      (in  seconds)  that  a  link  must  be  underutilized before it is
      dropped.  It MAY only be included in Access-Accept packets.

   A summary of the MS-Link-Drop-Time-Limit Attribute  format  is  given



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   below.  The fields are transmitted left to right.

   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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Vendor-Type | Vendor-Length |             Value
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
            Value (cont)         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Vendor-Type
      15 for MS-Link-Drop-Time-Limit

   Vendor-Length
      6

   Value
      The  Value field represents the number of seconds that a link must
      be underutilized (i.e., display bandwidth  utilization  below  the
      threshold    specified    in   the   MS-Link-Utilization-Threshold
      Attribute) before the link is dropped.


5.  Table of Attributes

The following table provides a guide to which of  the  above  attributes
may be found in which kinds of packets, and in what quantity.

   Request Accept Reject Challenge Acct-Request #  Attribute
   0       0-1    0      0         0            13 MS-BAP-Usage
   0       0-1    0      0         0            14 MS-Link-Utilization-Threshold
   0       0-1    0      0         0            15 MS-Link-Drop-Time-Limit

The following table defines the meaning of the above table entries.

   0     This attribute MUST NOT be present in packet.
   0+    Zero or more instances of this attribute MAY be present in packet.
   0-1   Zero or one instance of this attribute MAY be present in packet.


6.  Security Considerations

None.








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7.  Acknowledgements

Thanks  to  Narendra  Gidwani  (nareng@microsoft.com)  and  Aydin Edguer
(edguer@MorningStar.com) for useful comments.


8.  Expiration Date

This document expires August 28, 1998.


9.  Chair's Address

The RADIUS Working Group can be contacted via the current chair:

   Carl Rigney
   Livingston Enterprises
   4464 Willow Road
   Pleasanton, California  94588

   Phone: +1 510 426 0770
   E-Mail: cdr@livingston.com


10.  Author's Address

Questions about this memo can also be directed to:

   Glen Zorn
   Microsoft Corporation
   One Microsoft Way
   Redmond, Washington 98052

   Phone: +1 425 703 1559
   FAX:   +1 425 936 7329
   EMail: glennz@microsoft.com


11.  References

[1]  Sklower, K., et. al., "The PPP Multilink Protocol (MP)", RFC  1990,
     August 1996

[2]  Richards,  C. and Smith, K., "The PPP Bandwidth Allocation Protocol
     (BAP) The PPP Bandwidth Allocation  Control  Protocol  (BACP)"  RFC
     2125, March 1997





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[3]  Bradner,  S.,   "Key  words for use in RFCs to Indicate Requirement
     Levels", RFC 2119, March 1997

[4]  Rigney, C., et. al., "Remote Access  Dial  In  User  Service",  RFC
     2138, April 1997














































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