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Versions: 00

Network Working Group                                           B. Cheng
Internet-Draft                                                D. Wiggins
Intended status: Standards Track                      Lincoln Laboratory
Expires: April 30, 2017                                        L. Berger
                                                 LabN Consulting, L.L.C.
                                                        October 27, 2016


             DLEP DiffServ Aware Credit Windowing Extension
             draft-cheng-manet-dlep-da-credit-extension-00

Abstract

   This document defines an extension to the DLEP protocol that enables
   a DiffServ aware credit-windowing scheme for destination-specific
   flow control.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
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   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on April 30, 2017.

Copyright Notice

   Copyright (c) 2016 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
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   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.



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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Key Words . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Extension Overview  . . . . . . . . . . . . . . . . . . . . .   3
   3.  Extension Usage and Identification  . . . . . . . . . . . . .   4
   4.  Extension Messages  . . . . . . . . . . . . . . . . . . . . .   4
     4.1.  Credit Control Message  . . . . . . . . . . . . . . . . .   4
     4.2.  Credit Control Response Message . . . . . . . . . . . . .   5
   5.  Extension Data Items  . . . . . . . . . . . . . . . . . . . .   5
     5.1.  Queue Parameters  . . . . . . . . . . . . . . . . . . . .   5
     5.2.  DiffServ Aware (DA) Credit Grant  . . . . . . . . . . . .   8
     5.3.  DiffServ Aware (DA) Credit Window Status  . . . . . . . .  10
     5.4.  DiffServ Aware (DA) Credit Request  . . . . . . . . . . .  11
   6.  Compatibility . . . . . . . . . . . . . . . . . . . . . . . .  12
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  13
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  13
     8.1.  Extension Type Value  . . . . . . . . . . . . . . . . . .  13
     8.2.  Message Values  . . . . . . . . . . . . . . . . . . . . .  13
     8.3.  Data Item Values  . . . . . . . . . . . . . . . . . . . .  14
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  14
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  14
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  14
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  15

1.  Introduction

   The Dynamic Link Event Protocol (DLEP) is defined in
   [I-D.ietf-manet-dlep].  It provides the exchange of link related
   control information between DLEP peers.  DLEP peers are comprised of
   a modem and a router.  DLEP defines a base set of mechanisms as well
   as support for possible extensions.  This document defines one such
   extension.

   The base DLEP specification does not include any flow control
   capability.  There are various flow control theoretically possible
   with DLEP.  For example, a credit-windowing scheme for destination-
   specific flow control which provides aggregate flow control for both
   modem and routers has been proposed in
   [I-D.ietf-manet-credit-window].

   This document defines a DLEP extension which provides flow control
   for DiffServ [RFC2475] traffic sent from a router to a modem.  Flow
   control is provided for multiple DSCPs (differentiated services
   codepoint), which are grouped into logical sets of logical queues.
   The extension defined in this document is referred to as "DiffServ
   Aware Credit Windowing" or, more simply, the "DA Credit" extension.




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   This document defines a new DLEP Extension Type Value in Section 3
   which is used to indicate the use of the extension.  Two new messages
   are defined in Section 4, and four new DLEP Data Items in Section 5.

1.1.  Key Words

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14, RFC 2119 [RFC2119].

2.  Extension Overview

   The DA Credit extension can be used to support credit based flow
   control of traffic sent from a router to a modem.  The extension can
   be used to support DiffServ and non-DiffServ based flow control.
   Both types of DLEP endpoints, i.e., a router and a modem, negotiate
   the use of extension during session initialization, see Section 5.2
   [I-D.ietf-manet-dlep].

   When the extension is to be used, a modem passes to a router its
   known DSCPs, if any.  DSCPs are grouped by logical queues, each of
   which are given a logical queue index.  The queue index zero (0) is
   special and is used for any DSCP value, including 0, which is not
   otherwise identified by the modem.  The modem also provides a size,
   in bytes, of the logical queue for informative and, potential, future
   uses.  Currently, only DSCP to logical queue index value mapping is
   used in flow control operation.

   The DA Credit extension supports credit based flow control on a per
   MAC address destination, per queue index basis.  Modems provide the
   initial size of the associated "Credit Window", i.e., the amount in
   octets (bytes) that may be sent by the router to the modem, when a
   MAC destination becomes reachable and, optionally, when its rate
   information changes.  "Credit Increments", i.e., increases in a
   Credit Window size, are provided using new "Credit Control" messages.
   A router provides its view of the Credit Window, which is known as
   "status", in Destination Up Response and the new "Credit Control
   Response" messages.  Routers can also request credits using the new
   "Credit Control" message.

   Credit information, both grants and status, is provided in new credit
   grant related data items.  Each data item contains a single credit
   value that applies to one or more queue indexes.  Different (grant
   and status) values for different queue indexes can be provided in a
   single message by including multiple grant data items.  The values
   indicate a number of octets (bytes), including MAC headers on the
   router to modem link, that may be sent.



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   Note that credit information related to different destination MAC
   addresses is always passed in different DLEP messages.

3.  Extension Usage and Identification

   The use of the extension defined in this document SHOULD be
   configurable.  To indicate that the DiffServ Aware Credit Windowing
   Extension is to be used, an implementation MUST include the DiffServ
   Aware Credit Windowing Type Value in the Extensions Supported Data
   Item.  The Extensions Supported Data Item is sent and processed
   according to [I-D.ietf-manet-dlep].

   The DiffServ Aware Credit Windowing Extension Type Value is TBA1, see
   Section 8.

4.  Extension Messages

   Two new messages are defined by this extension: the Credit Control
   and the Credit Control Response message.  Sending and receiving both
   message types MUST be supported by any implementation that advertises
   use of this extension per Section 3.

4.1.  Credit Control Message

   Credit Control Messages are sent by modems to provide Credit
   Increments.  For messages sent by modems, only one message per MAC
   address can be outstanding at one time.  That is, a modem MUST NOT
   send a second (or any subsequent) message containing the same MAC
   Address until a Credit Control Response message is received from its
   peer router with that MAC address.

   Credit Control Messages MAY be sent by routers, e.g., to request
   credits or provide window status.  No specific response message is
   required from a message transaction perspective.

   [TBD: Should anything be said about sending, or limiting, multiple
   credit requests?]

   The Message Type value in the DLEP Message Header is set to TBA2.

   The message MUST contain a DLEP MAC Address Data Item.

   A message sent by a modem, MUST contain one or more DiffServ Aware
   Credit Grant data items as defined below in Section 5.2.  A router
   receiving this message MUST respond with a Credit Control Response
   Message.





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   A message sent by a router, MUST contain the DiffServ Aware Credit
   Request data item defined below in Section 5.4.  A modem receiving
   this message MUST provide a Credit Increment for the indicated MAC
   address and queue indexes via a new Credit Control Message.

   Specific processing associated with each Credit data item is provided
   below.

4.2.  Credit Control Response Message

   Credit Control Response Messages are sent by routers to report the
   current Credit Window for a destination.

   The Message Type value in the DLEP Message Header is set to TBA3.

   The message MUST contain a DLEP MAC Address Data Item.

   A message sent by a router, MUST contain one or more DiffServ Aware
   Credit Window Status data items as defined below in Section 5.3.

   Specific processing associated with the DA Credit Window Status data
   item is provided below.

5.  Extension Data Items

   Four data items are defined by this extension.  The Queue Parameters
   Data Item is used by a modem to provide information on the DSCPs it
   uses in forwarding.  The DA Credit Grant is used by a modem to
   provide credits to a router.  The DA Credit Request is used by a
   router to request additional credits.  The DA Credit Window Status is
   used to advertise the sender's view of number of available credits
   for synchronization purposes.

   The defined data items and operations are similar to those found in
   [I-D.ietf-manet-credit-window].  One notable difference from this
   extension is that in this document credits are never provided by the
   router to the modem.

5.1.  Queue Parameters

   The Queue Parameters Data Item is used by a modem to indicate DSCP
   values that may be independently controlled.  This data item MUST be
   included in a Session Initialization Response Message that also
   contains the DiffServ Aware Credit Windowing Extension Type Value in
   the Extensions Supported Data Item.  Updates to these parameters MAY
   be sent by a modem by including the data item in Session Update
   Messages.




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   The Queue Parameters Data Item identifies DSCPs based on groups of
   logical queues.  The number of logical queues is variable as is the
   number of DSCPs associated with each queue.  A queue size (in bytes)
   is provided for informational purposes.  An implementation that does
   not support DSCPs would indicate 1 queue with 0 DSCPs, and the number
   of bytes that may be in its associated link transmit queue.

   The format of the Queue Parameters Data Item is:

        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       | Data Item Type                | Length                        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |   Num Queues  | Scale |              Reserved                 |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |Num DSCPs Q0(0)|             Queue Size Q0                     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       | Num DSCPs Q1  |             Queue Size Q1                     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       | Num DSCPs Q2  |             Queue Size Q2                     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       :                                ...                            :
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       | Num DSCPs Qn  |             Queue Size Qn                     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |  DS Field Q1  |  DS Field Q1  |  DS Field Q1  |  DS Field Q2  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       :                                ...            |  DS Field Qn  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Data Item Type:  TBA4

   Length:  Variable

      Per [I-D.ietf-manet-dlep] Length is the number of octets in the
      data item, excluding the Type and Length fields.

   Num Queues:

      An 8-bit unsigned integer indicating the number of queues
      represented in the data item.  This field MUST contain a value of
      at least one (1).  Note that this number is one larger than the
      largest queue index value included in the data item.

   Scale:





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      An 4-bit unsigned integer indicating the scale used in the Queue
      Size fields.  The valid values are:

         Value  Scale
         ------------
             0   B - Bytes     (Octets)
             1  KB - Kilobytes (B/1024)
             2  MB - Megabytes (KB/1024)
             3  GB - Gigabytes (MB/1024)

   Reserved:

      MUST be set to zero by the sender (a modem) and ignored by the
      receiver (a router).

   Num DSCPs Qn:

      An 8-bit unsigned integer indicating the number of DSCPs
      associated with the indexed queue.  Other than the special case
      covered in the next paragraph, this field MUST contain a value of
      at least one (1).  Queue indexes start at zero (0) and the maximum
      queue index "Qn" is one less than the value carried in the Num
      Queues field.  Queue indexes are implicit in the position in the
      data item.

      Queue index zero "Q0" is a special case.  It is used for any
      traffic that does not carry a DSCP value represented in the data
      item.  Therefore the value of the Queue index zero field, "Num
      DSCPs Q0", field MUST be zero (0).

   Queue Size Qn:

      A 24-bit unsigned integer representing the size, in the octet
      scale indicated by the Scale field, of the queue supporting
      traffic with the DSCPs associated with the queue index.

   DS Field Qn:

      The data item contains a sequence of 8 bit DS Fields.  The
      position in the sequence identifies the associated queue index.
      The number of DS Fields present should equal the sum of all Num
      DSCPs field values.

      The DS Field structure is the same as [RFC2474].







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           0   1   2   3   4   5   6   7
         +---+---+---+---+---+---+---+---+
         |         DSCP          |  CU   |
         +---+---+---+---+---+---+---+---+

           DSCP: differentiated services codepoint
           CU:   currently unused, MUST be zero

5.2.  DiffServ Aware (DA) Credit Grant

   The DiffServ Aware, or DA, Credit Grant data item is used by a modem
   to provide credits to a router.  One or more DA Credit Grant data
   items MAY be carried in the DLEP Destination Up, Destination Announce
   Response, Destination Update, and Credit Control messages.  Multiple
   DA Credit Grant data items in a single message are used to indicated
   different credit values for different logical queues.

   In Destination type messages, this data item provides the total
   number of octets available in the Credit Window to the destination
   indicated in the message for the specified logical queues.  In the
   Credit Control message, this data item provides an additional number
   of octets to be added to the Credit Window to the destination
   indicated in the message for the specified logical queues.

   Logical queues are identified using a Queue Index as defined above in
   Section 5.1.  Multiple Queue Indexes MAY be present to allow for the
   case where same credit information applies to multiple queues.  As
   mentioned above, multiple DA Credit Grant Data Items MAY be present
   to provide different queue-specific credit information in one
   message.  The special Queue Index value of 255 is used to indicate
   that the credit information applies to all queues.

   The format of the DA Credit Grant Data Item is:

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | Data Item Type                | Length                        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                         Credit Value                          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                         Credit value                          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  Queue Index  |               ...                             :
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      :                                ...            |  Queue Index  |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+




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   Data Item Type:  TBA5

   Length:  Variable

      Per [I-D.ietf-manet-dlep], Length is the number of octets in the
      data item, excluding the Type and Length fields.  It will equal 8
      plus the number of Queue Index fields carried in the data item and
      MUST be at least 9.

   Credit Value:

      A 64-bit unsigned integer representing the credits, in octets, to
      be applied to the Credit Window.  This value includes MAC headers
      as seen on the link between the modem and router.

   Queue Index:

      One or more 8-bit fields used to indicate a queue index defined by
      a Queue Parameters Data Item.  The special value of 255 indicates
      that the information in the data item applies to all queue
      indexes.

   Receive processing of this data item is based on the message in which
   it is carried.  When this data item is received in a Destination type
   message, the Credit Window of the indicated destination MAC address
   and indicated queue indexes MUST be set to the value contained in the
   Credit Value field.

   When this data item is received in a Credit Control message, the
   Credit Window of the indicated destination MAC address and indicated
   queue indexes MUST be increased by the value contained in the Credit
   Value field.  If the increase results in a window overflow, i.e., the
   Credit Window resulting after the increase is smaller than the
   original Credit Window, the Credit Window must be set to its maximum
   (0xFFFFFFFFFFFFFFFF).

   Independent of the received message, the receiving router MUST send a
   DA Credit Window Status data item or items reflecting the resulting
   Credit Window value of each modified queue index.  When the Credit
   Grant data item is received in a Destination Up message, the DA
   Credit Window Status data item(s) MUST be sent in the corresponding
   Destination Up Response message.  In all other cases, the a Credit
   Control message MUST be sent.








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5.3.  DiffServ Aware (DA) Credit Window Status

   The DiffServ Aware, or DA, Credit Window Status data item is used by
   a router to report the current Credit Window to its peer modem.  One
   or more DA Credit Window Status data items MAY be carried in a
   Destination Up Response message or a Credit Control Response message.
   As discussed above, the Destination Up Response message is used when
   the data item is sent in response to a Destination Up message, and
   the Credit Control Response message is sent in response to a Credit
   Control message.  Multiple DA Credit Window Status data items in a
   single message are used to indicated different credit window values
   for different logical queues.

   Similar to the DA Credit Grant, logical queues are identified using a
   Queue Index as defined above in Section 5.1.  Multiple Queue Indexes
   MAY be present to allow for the case where same credit information
   applies to multiple queues.  Multiple DA Credit Window Status Data
   Items are used to provide different queue-specific credit window
   information in one message.  The special Queue Index value of 255 is
   used to indicate that the Credit Window information applies to all
   queues.

   The format of the DA Credit Window Status Data Item is:

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | Data Item Type                | Length                        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                         Credit Window                         :
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      :                         Credit Window                         |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  Queue Index  |               ...                             :
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      :                                ...            |  Queue Index  |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Data Item Type:  TBA6

   Length:  Variable

      Per [I-D.ietf-manet-dlep] Length is the number of octets in the
      data item, excluding the Type and Length fields.  It will equal 8
      plus the number of Queue Index fields carried in the data item and
      MUST be at least 9.

   Credit Window:



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      A 64-bit unsigned integer, indicating the current number of
      credits, in octets, available for the router to send to the modem.
      This is referred to as the Modem Receive Window in
      [I-D.ietf-manet-credit-window].

   Queue Index:

      One or more 8-bit fields used to indicate a queue index defined by
      a Queue Parameters Data Item.  The special value of 255 indicates
      that the information in the data item applies to all queue
      indexes.

   The receiving modem SHOULD check the received Credit Window value
   against the outstanding credits available at the time the last Credit
   Increment associated with the indicated MAC address and Queue Indexes
   were sent.  If the values significantly differ, i.e., greater than
   can be accounted for based on observed data frames, then the modem
   SHOULD send a Destination Update message carrying a DA Credit Grant
   data item to reset the associated Credit Window(s) to the data item
   indicated value.  Multiple values and queue indexes SHOULD be
   combined into a single Destination Update Control message when
   possible.  Alternatively, and also in cases where there are small
   differences, the modem MAY adjust the values sent in DA Credit Grant
   data items to account for the reported Credit Window.

5.4.  DiffServ Aware (DA) Credit Request

   The DiffServ Aware, or DA, Credit Request Data Item data item is used
   by a router to request additional credits for a specific destination
   and Queue Index associated Credit window.  DA Credit Request data
   items are carried in Credit Control messages, and only one DA Credit
   Request data item SHOULD be present in a message.

   Logical queues are identified using a Queue Index as defined above in
   Section 5.1.  Multiple Queue Indexes MAY be present to allow for the
   case where the credit request applies to multiple queues.  The
   special Queue Index value of 255 is used to indicate that a credit
   request is being made across all queues.

   The format of the DA Credit Request Data Item is:











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       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | Data Item Type                | Length                        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  Queue Index  |               ...                             :
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      :                                ...            |  Queue Index  |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   [LB note: a list of Queue Indexes is now supported as is special
   value 255.]

   Data Item Type:  TBA7

   Length:  Variable

      Per [I-D.ietf-manet-dlep] Length is the number of octets in the
      data item, excluding the Type and Length fields.  It will equal
      the number of Queue Index fields carried in the data item and MUST
      be at least 1.

   Queue Index:

      One or more 8-bit fields used to indicate a queue index defined by
      a Queue Parameters Data Item.  The special value of 255 indicates
      that the request applies to all queue indexes.

   A modem receiving this data item MUST provide a Credit Increment for
   the indicated MAC address and queue indexes via a DA Credit Grant
   carried in a new Credit Control Message.  Multiple values and queue
   indexes SHOULD be combined into a single Credit Control message when
   possible.

6.  Compatibility

   Sessions established with both peers identified as supporting the
   DiffServ Aware Credit Windowing Extension Type, see Section 3, SHOULD
   NOT use the [I-D.ietf-manet-credit-window] defined Credit data items.
   If a node supporting the extension defined in this document, receives
   a [I-D.ietf-manet-credit-window] defined data item, the recipient
   MUST treat the received credit information as applying to Queue Index
   zero (0).








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7.  Security Considerations

   The extension introduces a DiffServ awareness to the mechanisms
   defined in [I-D.ietf-manet-credit-window].  The extension does not
   inherently introduce any additional threats above those documented in
   [I-D.ietf-manet-dlep].  The approach taken to Security in that
   document and [I-D.ietf-manet-credit-window] apply equally when
   running the extension defined in this document.

8.  IANA Considerations

   This document requests the assignment of 5 values by IANA.  All
   assignments are to registries defined by [I-D.ietf-manet-dlep].

8.1.  Extension Type Value

   This document requests 1 new assignment to the DLEP Extensions
   Registry named "Extension Tyoe Values" in the range with the
   "Specification Required" policy.  The requested value is as follows:

                +------+---------------------------------+
                | Code | Description                     |
                +------+---------------------------------+
                | TBA1 | DiffServ Aware Credit Windowing |
                +------+---------------------------------+

                  Table 1: Requested Extension Type Value

8.2.  Message Values

   This document requests 2 new assignments to the DLEP Message Registry
   named "Message Values" in the range with the "Specification Required"
   policy.  The requested values are as follows:

                  +-----------+-------------------------+
                  | Type Code | Description             |
                  +-----------+-------------------------+
                  | TBA2      | Credit Control          |
                  |           |                         |
                  | TBA3      | Credit Control Response |
                  +-----------+-------------------------+

                     Table 2: Requested Message Values








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8.3.  Data Item Values

   This document requests 4 new assignments to the DLEP Data Item
   Registry named "Data Item Values" in the range with the
   "Specification Required" policy.  The requested values are as
   follows:

                  +-----------+-------------------------+
                  | Type Code | Description             |
                  +-----------+-------------------------+
                  | TBA4      | Queue Parameters        |
                  |           |                         |
                  | TBA5      | DA Credit Grant         |
                  |           |                         |
                  | TBA6      | DA Credit Window Status |
                  |           |                         |
                  | TBA7      | DA Credit Request       |
                  +-----------+-------------------------+

                    Table 3: Requested Data Item Values

9.  References

9.1.  Normative References

   [I-D.ietf-manet-dlep]
              Ratliff, S., Jury, S., Satterwhite, D., Taylor, R., and (.
              (Unknown), "Dynamic Link Exchange Protocol (DLEP)", draft-
              ietf-manet-dlep-24 (work in progress), July 2016.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <http://www.rfc-editor.org/info/rfc2119>.

9.2.  Informative References

   [I-D.ietf-manet-credit-window]
              Ratliff, S., "Credit Windowing extension for DLEP", draft-
              ietf-manet-credit-window-04 (work in progress), April
              2016.

   [RFC2474]  Nichols, K., Blake, S., Baker, F., and D. Black,
              "Definition of the Differentiated Services Field (DS
              Field) in the IPv4 and IPv6 Headers", RFC 2474,
              DOI 10.17487/RFC2474, December 1998,
              <http://www.rfc-editor.org/info/rfc2474>.




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Internet-Draft          DLEP DA Credit Extension            October 2016


   [RFC2475]  Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z.,
              and W. Weiss, "An Architecture for Differentiated
              Services", RFC 2475, DOI 10.17487/RFC2475, December 1998,
              <http://www.rfc-editor.org/info/rfc2475>.

Authors' Addresses

   Bow-Nan Cheng
   Lincoln Laboratory
   Massachusetts Institute of Technology
   244 Wood Street
   Lexington, MA  02420-9108

   Email: bcheng@ll.mit.edu


   David Wiggins
   Lincoln Laboratory
   Massachusetts Institute of Technology
   244 Wood Street
   Lexington, MA  02420-9108

   Email: David.Wiggins@ll.mit.edu


   Lou Berger
   LabN Consulting, L.L.C.

   Email: lberger@labn.net






















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