Network Working Group                                 H. Hazewinkel, Ed.
Request for Comments: 3747                                         I.Net
Category: Standards Track                                D. Partain, Ed.
                                                                Ericsson
                                                              April 2004

The Differentiated Services Configuration MIB

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

Abstract

   This memo describes a MIB module that provides a conceptual layer
   between high-level "network-wide" policy definitions that effect
   configuration of the Differentiated Services (diffserv) subsystem and
   the instance-specific information that would include such details as
   the parameters for all the queues associated with each interface in a
   system.  This essentially provides an interface for configuring
   differentiated services at a conceptually higher layer than that of
   the Differentiated Services MIB.

   1.  The Internet-Standard Management Framework . . . . . . . . . .  2
   2.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  2
   3.  Other Documents. . . . . . . . . . . . . . . . . . . . . . . .  3
   4.  Relationship to other MIBs . . . . . . . . . . . . . . . . . .  3
       4.1.  The Policy-based Management MIB Module . . . . . . . . .  3
       4.2.  The Differentiated Services MIB Module . . . . . . . . .  4
   5.  The Differentiated Services Configuration MIB Module Design. .  5
   6.  Template Cloning . . . . . . . . . . . . . . . . . . . . . . .  6
       6.1.  An Approach to Template Cloning. . . . . . . . . . . . .  6
       6.2.  Example. . . . . . . . . . . . . . . . . . . . . . . . .  7
             6.2.1.  The Initial Situation. . . . . . . . . . . . . .  8
             6.2.2.  The Configuration Template . . . . . . . . . . .  9
             6.2.3.  Applying the Template. . . . . . . . . . . . . . 11
             6.2.4.  Applying the Template Using SNMP Messages. . . . 14
   7.  Managed Objects Definitions (MIB Module) . . . . . . . . . . . 15
   8.  Security Considerations. . . . . . . . . . . . . . . . . . . . 20
   9.  Acknowledgments. . . . . . . . . . . . . . . . . . . . . . . . 22
   10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 22
       10.1. Normative References . . . . . . . . . . . . . . . . . . 22
       10.2. Informative References . . . . . . . . . . . . . . . . . 23
   11. Editors' Addresses . . . . . . . . . . . . . . . . . . . . . . 23
   12. Full Copyright Statement . . . . . . . . . . . . . . . . . . . 24

1. The Internet-Standard Management Framework

   For a detailed overview of the documents that describe the current
   Internet-Standard Management Framework, please refer to section 7 of
   RFC 3410 [RFC3410].

   Managed objects are accessed via a virtual information store, termed
   the Management Information Base or MIB.  MIB objects are generally
   accessed through the Simple Network Management Protocol (SNMP).
   Objects in the MIB are defined using the mechanisms defined in the
   Structure of Management Information (SMI).  This memo specifies a MIB
   module that is compliant to the SMIv2, which is described in STD 58,
   RFC 2578 [RFC2578], STD 58, RFC 2579 [RFC2579] and STD 58, RFC 2580
   [RFC2580].

2. Introduction

   This memo defines a MIB module that can be used to convey management
   information about desired network-wide Differentiated Services based
   policy behavior.  This module is designed to integrate with the
   Differentiated Services MIB module [RFC3289] in order to provide
   template configurations for the Differentiated Services MIB module.
   The MIB module defined in this memo (the DIFFSERV-CONFIG-MIB) may be

   used in combination with the Policy-based Management MIB module
   [PMMIBDR], but that is not a requirement.  Without the Policy-based
   Management MIB module, a management application must emulate behavior
   provided by the Policy-based Management MIB using equivalent "low-
   level" SNMP operations in normal manager/agent communication.

   Together, this memo, [RFC3289], and [PMMIBDR] represent an instance
   of an integrated architecture for both device-specific and network-
   wide policy (configuration) management, which is fully integrated
   with the Internet Standard Management Framework.

   The Differentiated Services MIB module [RFC3289] operates on a device
   level.  The MIB module in this memo, the DIFFSERV-CONFIG-MIB, creates
   a coherent configuration management view as an umbrella over
   [RFC3289].  That is, the DIFFSERV-CONFIG-MIB provides a conceptual
   Application Program Interface (API) for configuration of the
   Differentiated Services parameters.  Since the Differentiated
   Services MIB module is able to maintain configuration information,
   the DIFFSERV-CONFIG-MIB configuration API consists only of
   configuration template information and the start of the so-called
   functional datapath.

3. Other Documents

   It is assumed that the reader is familiar with Differentiated
   Services ([RFC2474] and [RFC2475]), the Policy-based Management MIB
   ([PMMIBDR]), and "Configuring Networks and Devices With SNMP"
   ([RFC3512]).  These documents include all of the necessary
   terminology for understanding this memo.  However, note that use of
   the MIB module in this memo does not require the use of [PMMIBDR].
   [RFC3512] also provides an example MIB module which may help in
   understanding the relationship between DIFFSERV-CONFIG-MIB and the
   Differentiated Services MIB in [RFC3289].

4. Relationship to other MIBs

   In this section, we describe the relationship of this MIB module to
   other MIB modules.  The overall architecture used for policy
   configuration management is described in [PMMIBDR].

4.1. The Policy-based Management MIB Module

   [PMMIBDR] defines a MIB module that enables policy-based
   configuration management of infrastructure using the Internet
   Standard Management Framework.  The document includes a table for
   configuring policies to be implemented, tables for storing the roles
   of elements on a particular device, a table for representing the
   capabilities of a device with respect to policy management, a table

   for referencing elements affected by a policy, as well as other
   infrastructure.  There is no requirement that [PMMIBDR] be used in
   conjunction with the MIB module defined in this memo.

   See [PMMIBDR] for a full description of the policy-based
   configuration framework it provides.

4.2. The Differentiated Services MIB Module

   The Differentiated Services MIB module [RFC3289] provides a common
   set of managed objects useful for configuring Differentiated Services
   parameters on a Differentiated Services capable device.  This is what
   is referred to as instance-level configuration.  It is the alteration
   of the instance-level information in that MIB module which may be
   done using the objects in the MIB module defined in this memo.

   It is recognized that vendors may include additional managed objects
   in their devices (via vendor-specific MIB modules) for configuring
   Differentiated Services parameters.  If a vendor chooses to use the
   objects defined in this memo for configuration, the vendor should
   provide additional managed objects in a similar approach as defined
   for the Differentiated Services MIB module.

   Since the managed objects of the Differentiated Services MIB
   [RFC3289] are not directly associated with an instance (interface and
   interface direction), the same managed objects can be used for
   traffic treatment configuration templates in a Differentiated
   Services capable device and can then be applied on multiple
   instances.  Therefore, the tables as defined in the Differentiated
   Services MIB can be used directly for template configuration
   purposes.  Those tables are:

      - diffServClfrTable
      - diffServClfrElementTable
      - diffServMultiFieldClfrTable
      - diffServMeterTable
      - diffServTBParamTable
      - diffServActionTable
      - diffServDscpMarkActTable
      - diffServCountActTable
      - diffServAlgDropTable
      - diffServRandomDropTable
      - diffServQTable
      - diffServSchedulerTable
      - diffServMinRateTable
      - diffServMaxRateTable

   Readers familiar with the Differentiated Services MIB will notice
   that these are all templates.  Only the diffServDataPathTable defines
   a managed instance for Differentiated Services traffic treatment by
   its indexes of the interface and its direction.  This also allows the
   tables mentioned above to be used as a configuration template without
   defining anything directly related to a managed instance.

5. The Differentiated Services Configuration MIB Module Design

   The Differentiated Services Configuration MIB module (in this memo)
   of the SNMP-based configuration management framework is positioned
   between the Policy-based Management MIB module and the instance-
   specific Differentiated Services MIB module as described above.

   The MIB module found in this memo is designed to maintain
   configuration templates for the Differentiated Services MIB [RFC3289]
   module.  The module only has a template table that describes a
   Differentiated Services traffic treatment by providing the starting
   pointer of the functional datapath.  The templates represent a
   specific configuration of traffic treatment in a functional datapath
   of a Differentiated Services capable device.  To avoid duplication of
   managed objects, the actual templates defining the functional
   datapath are defined in the Differentiated Services MIB module.
   These are also used for the management of the instances.  Therefore,
   the implementation of the DIFFSERV-CONFIG-MIB module uses the tables
   defined in the Differentiated Services MIB.  As soon as a
   configuration is made active via the POLICY-MANAGEMENT-MIB or using
   normal SNMP operations, the configuration defined within this MIB
   module will be instantiated in the DIFFSERV-MIB.

   Note that this is a conceptual process.  That is, the configuration
   may not actually go through an API available in the subsystem which
   implements the DIFFSERV-MIB module.  However, configuration via the
   DIFFSERV-CONFIG-MIB module will alter the same instrumentation as the
   DIFFSERV-MIB module whether it does it via the DIFFSERV-MIB module or
   not.

   The Differentiated Services Configuration MIB module only needs to
   define a starting point of a traffic treatment configuration
   template.  This table is similar to the diffServDataPathTable
   [RFC3289].  However, it has a semantic difference in that the
   diffServDataPathTable is associated with an instance (interface and
   interface direction), whereas the diffServConfigTable in this memo is
   not.

   Unlike most MIB modules, changes to the managed objects in this MIB
   module do not cause a change in the external/traffic behavior of the
   device.  This MIB module is used to set up per-hop-behavior
   configurations.  As soon as configurations are made active via the
   POLICY-MANAGEMENT-MIB or SNMP operations, the configurations defined
   within this MIB module will be instantiated in the DIFFSERV-MIB.

   The only table in this MIB module is the diffServConfigTable, which
   provides managed objects for registering traffic treatment
   configurations used in differentiated services.  The sole purpose of
   this table is to provide the starting point for a traffic treatment
   configuration template.  The traffic treatment itself is performed by
   functional datapath elements [RFC3289].

6. Template Cloning

   The concept of the DIFFSERV-CONFIG-MIB is based on having traffic
   treatment configuration templates.  The templates provide a set of
   configuration values that provide a particular behavior, such as
   Expedited Forwarding traffic treatment, in the functional datapath.
   The template (or functional datapath) is similar to a linked list
   from a starting point and each (functional datapath) element is
   connected to the next element via the so-called next RowPointer.

   The moment a template is activated (instantiated) on an interface and
   its interface direction, the template needs to be copied/cloned, so
   that the template remains as a template.  Note that the template is
   logically "locked" through the cloning process.  That is, the
   template cannot be changed part way through the cloning process.
   With the exception of the indices, the cloned template will be
   identical to the source template.

   A literal copy/clone of the template is not possible, since the same
   indices inside the element tables cannot be re-used.  The
   instantiation process must therefore generate a new index for each
   element.  As a result of this, the 'NEXT' pointers also need to be
   updated.  Otherwise, those will point to the template.

6.1. An Approach to Template Cloning

   What should a system containing Differentiated Services capabilities
   and Differentiated Services configuration capabilities do
   conceptually at the moment a template is activated on an interface?
   The following approach should not be considered implementation
   guidelines, but rather a conceptual explanation of what should be
   done.

      1) Get the index of the template to be activated
      2) Get RowPointer (current) from
            diffServConfigStart.index
            of the diffServConfigTable
      3) Check if RowPointer (current) exists
      4) Logically "lock" the entry (current) pointed to by
         RowPointer so that its values are not changed part way
         through the cloning process.
      5) Copy/Clone the entry (current) pointed to by RowPointer
            a) Get a new index for the entry
            b) Configure the new entry with the values
               of the entry to be cloned
            c) Update the NEXT pointer with a new RowPointer
               that pointed to the previous entry that was copied
               part of this template
      6) Store RowPointer of cloned entry as (previous) in order to
         update the NEXT pointer with the next cloned entry.
      7) Get the RowPointer of the next element in the template
         as (current)
      8) If (current) RowPointer does not equal zeroDotZero go to 4
      9) Logically "unlock" all the locked entries done by step 4).

   If a configuration/template is activated via a means other than a
   direct SNMP SET request, such as via the Policy-based Management MIB,
   the handling of the activation and potential error response code must
   be provided via that mechanism.  If a configuration/template is
   activated using SNMP SET requests, an accurate error response value
   must be returned.  For example, if a configuration/template has
   inconsistent values, the SNMP SET should return an error.  Whether
   the configuration is already finished is not of direct importance,
   since the SNMP SET response must be accurate.  On systems where the
   activation may take a long time, a response may be given prior to
   completion, but extra mechanisms must be provided to detect any
   errors.

6.2. Example

   This section provides an example of the process described in the
   previous section.  This example will show a Differentiated Services
   capable incoming (ingress) interface that only counts the traffic
   stream.  Then, with the policy-based configuration concept as defined
   in this document and in [PMMIBDR], a traffic marking configuration
   will be applied.  The example will walk the reader through all of the
   steps involved in this process.  Again, the use of [PMMIBDR] is
   simply an example and is not required.

      NOTE WELL:  For brevity and clarity, the example does not always
      show the complete entry (row) of a table.  The only objects shown
      are those needed for creating the row pointers to the next
      functional datapath element or needed to provide information about
      the specific parameters of the functional datapath elements.  The
      column named 'INDEX' always defines the complete index as defined
      for the associated entry.  In some cases, this is a combined index
      of multiple components.  Therefore, the names of the columns are
      omitted.

      Also note that the values Assured Forwarding and Expedited
      Forwarding are abstracted as DSCP(AF) and DSCP(EF) (respectively)
      or simply as AF and EF.  For the actual values refer to [RFC3289].

6.2.1. The Initial Situation

   The initial configuration is the existing configuration of an ingress
   interface.

      +------------------------------------------------------------+
      |   ingress functional datapath                              |
      |                        +----------+                        |
   -->|----------->----------->| count    |----------->----------->|-->
      |                        +----------+                        |
      +------------------------------------------------------------+

   This figure depicts a simple traffic treatment functional datapath
   for an ingress interface.  The functional datapath only consists of a
   count action.

   Within the DIFFSERV-MIB, this would be instantiated as follows.  Note
   that RowPointer objects must point to the first accessible columnar
   object in the conceptual row.  Thus, while perhaps more instructive
   to use the index value for the RowPointer object's value (e.g.,
   diffServCountActId.1) in the example, it would nonetheless be
   incorrect, and the first accessible columnar object has been used as
   should be done (e.g., diffServCountActOctets.1).

   diffServDataPathTable
   +-----------------+-----------------------------+--
   | INDEX           | diffServDataPathStart       |
   +-----------------+-----------------------------+--
   | ifIndex.ingress | diffServActionNext.1        |
   +-----------------+-----------------------------+--

   diffServActionTable
   +-------+--------------------+-------------------------+--
   | INDEX | diffServActionNext |diffServActionSpecific   |
   +-------+--------------------+-------------------------+--
   | 1     | 0.0                |diffServCountActOctets.1 |
   +-------+--------------------+-------------------------+--

   diffServCountActTable
   +-------+------------------------+--
   | INDEX | diffServCountActOctets |
   +-------+------------------------+--
   | 1     |                        |
   +-------+------------------------+--

6.2.2. The Configuration Template

   The following provides an example of a policy configuration in which
   traffic is classified by a specific IP filter, that results in two
   classifiers (one for the IP filter and one for match all).  Both
   streams are then metered, marked, and counted.  This is an example of
   usage on the edge (an ingress interface) of a Differentiated Services
   domain that wants to have Expedited Forwarding and Assured Forwarding
   marked traffic within the Differentiated Services domain.

   +------------------------------------------------------------+
   |   ingress functional datapath                              |
   |   +------------+   +-------+   +---------+   +---------+   |
   |   |            |   |       |   | action: |   | action: |   |
-->|-->| classifier |-->| meter |-->| mark EF |-->| count   |-->|----->
   |   | match <IP> |   |       |   |         |   |         |   |
   |   +------------+   +-------+   +---------+   +---------+   |
   |         |                 \                                |
   |         |                  \      +---------+              |
   |         |                   \     | action: |              |routing
   |         |                    * -->| dropper |              |core
   |         |                   /     |         |              |
   |         |                  /      +---------+              |
   |         V                 /                                |
   |   +------------+   +-------+   +---------+   +---------+   |
   |   |            |   |       |   | action: |   | action: |   |
   |   | classifier |-->| meter |-->| mark AF |-->| count   |-->|----->
   |   | match all  |   |       |   |         |   |         |   |
   |   +------------+   +-------+   +---------+   +---------+   |
   +------------------------------------------------------------+

   This figure depicts a policy configuration for ingress traffic
   treatment in a Differentiated Services capable device.  The

   configuration is represented as follows in the DIFFSERV-CONFIG-MIB
   module and the DIFFSERV-MIB module.

   Note that the original (existing) traffic treatment described in
   6.2.1 is also in the tables.

   Note also that in the diffServDscpMarkActTable, DSCP(EF) represents
   the DSCP value for Expedited Forwarding and DSCP(AF) represents the
   DSCP value for Assured Forwarding.

diffServConfigTable (in the MIB module in this memo)
+-------+-------------------------+---------------------------+--
| INDEX | diffServConfigStart     | diffServConfigDescr       |
+-------+-------------------------+---------------------------+--
| "foo" | diffServClfrStorage.1   | Example traffic treatment |
+-------+-------------------------+---------------------------+--

diffServClfrTable
+-------+---------------------+--------------------+
| INDEX | diffServClfrStorage | diffServClfrStatus |
+-------+---------------------+--------------------+
| 1     |                     |                    |
+-------+---------------------+--------------------+

diffServClfrElementTable (shares index with diffServClfrTable)
+-------+---------------------------+-------------------------------+--
| INDEX | diffServClfrElementNext   | diffServClfrElementPrecedence |
+-------+---------------------------+-------------------------------+--
| 1.1   |diffServMeterSucceedNext.1 | 1                             |
| 1.2   |diffServMeterSucceedNext.2 | 2                             |
+-------+---------------------------+-------------------------------+--

diffServMeterTable
+-------+--------------------------+-----------------------+--
| INDEX | diffServMeterSucceedNext |diffServMeterFailNext  |
+-------+--------------------------+-----------------------+--
| 1     | diffServActionNext.2     | diffServAlgDropType.1 |
| 2     | diffServActionNext.3     | diffServAlgDropType.1 |
+-------+--------------------------+-----------------------+--

diffServActionTable
+-------+----------------------+----------------------------+--
| INDEX | diffServActionNext   | diffServActionSpecific     |
+-------+----------------------+----------------------------+--
| 1     | 0.0                  | diffServCountActOctets.1   |
| 2     | diffServActionNext.4 | diffServDscpMarkActDscp.EF |
| 3     | diffServActionNext.5 | diffServDscpMarkActDscp.AF |
| 4     | 0.0                  | diffServCountActOctets.2   |
| 5     | 0.0                  | diffServCountActOctets.3   |
+-------+----------------------+----------------------------+--

diffServCountActTable
+-------+------------------------+--
| INDEX | diffServCountActOctets |
+-------+------------------------+--
| 1     |                        |
| 2     |                        |
| 3     |                        |
+-------+------------------------+--

diffServAlgDropTable
+-------+---------------------+-------------------------+--
| INDEX | diffServAlgDropType | diffServAlgDropSpecific |
+-------+---------------------+-------------------------+--
| 1     | alwaysDrop(5)       | 0.0                     |
+-------+---------------------+-------------------------+--

diffServDscpMarkActTable
+-------------------------+
| diffServDscpMarkActDscp |
+-------------------------+
| DSCP(EF)                |
| DSCP(AF)                |
+-------------------------+

6.2.3. Applying the Template

   Now we have the original ingress interface configuration and the
   policy configuration we want to apply to the actual interface.

   The example policy must provide the required Differentiated Services
   traffic treatment to all interfaces used by system administrators.
   The traffic treatment required is described in 6.2.2 above.

   Therefore, we have the following example policy which is configured
   via the POLICY-BASED-MANAGEMENT-MIB module (see [PMMIBDR]):

   if ( roleMatch("Administrator") )

   then
      /*
       * The $0 gets the "element" returned from the previous
       * statement.  the .1 at the end is the ingress interface
       * This sets, for example, diffServDataPathStart.3.1 to be
       * "diffServConfigStart.3.f.o.o" if interface 3 has the role
       * "Administrator".
       */
      setVar("diffServDataPathStart.$0.1",
              "diffServConfigStart.3.f.o.o", Oid)

   For our purposes, we only apply this on the inbound (ingress)
   direction of the interface.

   Note that although object descriptors are used in this PolicyScript
   example, the object identifiers must be used in the running script.
   For more information on policies and their syntax refer to [PMMIBDR].

   The following tables in this section provide the cloned entries in
   the tables of the DIFFSERV-MIB module.  All tables may have columns
   that contain contents or administrative objects that are not shown.
   These columns do not determine a function in the datapath and they
   are not shown for clarity of the cloning mechanism.

   Note that the original (existing) traffic treatment of 6.2.1 and
   6.2.2 are also in the tables.

diffServConfigTable
+-------+-------------------------+---------------------------+--
| INDEX | diffServConfigStart     | diffServConfigDescr       |
+-------+-------------------------+---------------------------+--
| "foo" | diffServClfrStorage.1   | Example traffic treatment |
+-------+-------------------------+---------------------------+--

diffServDataPathTable
+-----------------+-----------------------------+--
| INDEX           | diffServDataPathStart       |
+-----------------+-----------------------------+--
| ifIndex.ingress | diffServActionNext.2        |
+-----------------+-----------------------------+--

diffServClfrTable
+-------+---------------------+--------------------+
| INDEX | diffServClfrStorage | diffServClfrStatus |
+-------+---------------------+--------------------+
| 1     |                     |                    |
| 2     |                     |                    |
+-------+---------------------+--------------------+

diffServClfrElementTable
+-------+----------------------------+-------------------------------+--
| INDEX | diffServClfrElementNext    | diffServClfrElementPrecedence |
+-------+----------------------------+-------------------------------+--
| 1.1   | diffServMeterSucceedNext.1 | 1                             |
| 1.2   | diffServMeterSucceedNext.2 | 2                             |
| 2.3   | diffServMeterSucceedNext.3 | 1                             |
| 2.4   | diffServMeterSucceedNext.4 | 2                             |
+-------+----------------------------+-------------------------------+--

diffServMeterTable
+-------+--------------------------+-----------------------+--
| INDEX | diffServMeterSucceedNext | diffServMeterFailNext |
+-------+--------------------------+-----------------------+--
| 1     | diffServActionNext.2     | diffServAlgDropType.1 |
| 2     | diffServActionNext.3     | diffServAlgDropType.1 |
| 3     | diffServActionNext.6     | diffServAlgDropType.2 |
| 4     | diffServActionNext.7     | diffServAlgDropType.2 |
+-------+--------------------------+-----------------------+--

diffServActionTable
+-------+----------------------+----------------------------+--
| INDEX | diffServActionNext   | diffServActionSpecific     |
+-------+----------------------+----------------------------+--
| 1     | 0.0                  | diffServCountActOctets.1   |
| 2     | diffServActionNext.4 | diffServDscpMarkActDscp.EF |
| 3     | diffServActionNext.5 | diffServDscpMarkActDscp.AF |
| 4     | 0.0                  | diffServCountActOctets.2   |
| 5     | 0.0                  | diffServCountActOctets.3   |
| 6     | diffServActionNext.8 | diffServDscpMarkActDscp.EF |
| 7     | diffServActionNext.9 | diffServDscpMarkActDscp.AF |
| 8     | 0.0                  | diffServCountActOctets.4   |
| 9     | 0.0                  | diffServCountActOctets.5   |
+-------+----------------------+----------------------------+--

diffServCountActTable
+-------+------------------------+--
| INDEX | diffServActCountOctets |
+-------+------------------------+--
| 1     |                        |
| 2     |                        |
| 3     |                        |
| 4     |                        |
| 5     |                        |
+-------+------------------------+--

diffServAlgDropTable
+-------+---------------------+-------------------------+--
| INDEX | diffServAlgDropType | diffServAlgDropSpecific |
+-------+---------------------+-------------------------+--
| 1     | alwaysDrop(5)       | 0.0                     |
+-------+---------------------+-------------------------+--

diffServDscpMarkActTable
+-------------------------+
| diffServDscpMarkActDscp |
+-------------------------+
| DSCP(EF)                |
| DSCP(AF)                |
+-------------------------+

   As one can see in the example, the main elements from which a
   functional datapath is constructed are duplicated/copied/cloned.
   That process is needed in order to preserve the policy configuration
   for reuse at a later time.

   It is up to the SNMP agent to keep track of which network interfaces
   are under policy control and which policy rules are being used.  This
   avoids duplication of policy enforcement.  How the agent does this is
   an implementation issue.

   One can see that the old functional datapath configurations stay in
   the MIB module tables.  It is up to the SNMP agent implementation to
   decide whether to delete stale entries or keep them.  Garbage
   collection of stale entries is an implementation issue.

6.2.4. Applying the Template Using SNMP Messages

In this section, the above example is explained by using SNMP
communication between the SNMP "manager" and the SNMP "agent".

   In order to apply the template to all interfaces that have a role
   match of "Administrator," the SNMP manager must have a list of the
   roles of the interface.  This means the SNMP manager must do an
   SNMP-SET for all those interfaces.  This is expressed in the
   following pseudo code function.

   set_template_if_administrator_interface(
            <interface_list>, <template_name>
   ) {
      template_oid = SNMP-GET("diffServConfigStart.<template_name>");
      foreach interface (<ifRole_list>) {
         if (interface.role == "Administrator") {
            SNMP-SET("diffServDataPathStart.$interface.1",
                  Oid, template_oid);
         }
      }
   }

   For example, on a system with 3 interfaces, the following list would
   be known to the manager.  The first value indicates the interface
   number (ifIndex) and the second value is its role.

   interface_list IF_LIST = {
       { 1, ... , "Administrator", ... },
       { 2, ... , "User", ... },
       { 3, ... , "Administrator", ... } }

   This will result in the communication between a manager and agent of
   1 SNMP-GET and 2 SNMP-SETs:

   -  SNMP-GET("diffServConfigStart.3.f.o.o")
   -  SNMP-SET("diffServDataPathStart.1.1", Oid, "diffServActionNext.1")
   -  SNMP-SET("diffServDataPathStart.3.1", Oid, "diffServActionNext.1")

7. Managed Objects Definitions (MIB Module)

DIFFSERV-CONFIG-MIB DEFINITIONS ::= BEGIN
    IMPORTS

    OBJECT-TYPE, MODULE-IDENTITY,
    zeroDotZero, mib-2            FROM SNMPv2-SMI          -- [RFC2578]

    RowStatus, StorageType,
    RowPointer, DateAndTime       FROM SNMPv2-TC           -- [RFC2579]

    MODULE-COMPLIANCE,
    OBJECT-GROUP                  FROM SNMPv2-CONF         -- [RFC2580]

    SnmpAdminString               FROM SNMP-FRAMEWORK-MIB; -- [RFC3411]

diffServConfigMib MODULE-IDENTITY
    LAST-UPDATED "200401220000Z" -- 22 January 2004
    ORGANIZATION "SNMPCONF WG"
    CONTACT-INFO
       "SNMPCONF Working Group
        http://www.ietf.org/html.charters/snmpconf-charter.html
        WG mailing list: snmpconf@snmp.com

        Editors:
        Harrie Hazewinkel
        I.Net
        via Darwin 85
        20019 - Settimo Milanese (MI)
        Italy
        EMail: harrie@inet.it

        David Partain
        Ericsson AB
        P.O. Box 1248
        SE-581 12 Linkoping
        Sweden
        E-mail: David.Partain@ericsson.com"
    DESCRIPTION
        "This MIB module contains differentiated services
        specific managed objects to perform higher-level
        configuration management.  This MIB allows policies
        to use 'templates' to instantiate Differentiated
        Services functional datapath configurations to
        be assigned (associated with an interface and
        direction) when a policy is activated.

        Copyright (C) The Internet Society (2004).  This version
        of this MIB module is part of RFC 3747;  see the RFC
        itself for full legal notices."
    REVISION "200401220000Z" -- 22 January 2004
    DESCRIPTION
        "Initial version published as RFC 3747"
    ::= { mib-2 108 }

diffServConfigMIBObjects OBJECT IDENTIFIER ::= { diffServConfigMib 1 }
diffServConfigMIBConformance OBJECT IDENTIFIER ::=
                                               { diffServConfigMib 2 }

--
-- The Differentiated Services configuration objects
--

diffServConfigTable OBJECT-TYPE
    SYNTAX       SEQUENCE OF DiffServConfigEntry
    MAX-ACCESS   not-accessible
    STATUS       current
    DESCRIPTION
       "A table which defines the various per-hop-behaviors
       for which the system has default 'templates'."
    ::= { diffServConfigMIBObjects 2 }

diffServConfigEntry OBJECT-TYPE
    SYNTAX       DiffServConfigEntry
    MAX-ACCESS   not-accessible
    STATUS       current
    DESCRIPTION
       "An entry defining a per-hop-behavior.  Each entry in
       this table combines the various parameters (entries)
       into a specific per-hop-behavior.  Entries in this
       table might be defined by a vendor (pre-configured)
       or defined by a management application."
    INDEX { diffServConfigId }
    ::= { diffServConfigTable 1 }

DiffServConfigEntry ::= SEQUENCE {
    diffServConfigId           SnmpAdminString,
    diffServConfigDescr        SnmpAdminString,
    diffServConfigOwner        SnmpAdminString,
    diffServConfigLastChange   DateAndTime,
    diffServConfigStart        RowPointer,
    diffServConfigStorage      StorageType,
    diffServConfigStatus       RowStatus
}

diffServConfigId OBJECT-TYPE
    SYNTAX         SnmpAdminString (SIZE(1..116))
    MAX-ACCESS     not-accessible
    STATUS         current
    DESCRIPTION
      "A unique id for the per-hop-behavior policy for at
       least the SNMP agent.  For ease of administration the
       value may be unique within an administrative domain,
       but this is not required.

       The range of up to 116 octets is chosen to stay within
       the SMI limit of 128 sub-identifiers in an object
       identifier."
    ::= { diffServConfigEntry 1 }

diffServConfigDescr OBJECT-TYPE

    SYNTAX         SnmpAdminString
    MAX-ACCESS     read-create
    STATUS         current
    DESCRIPTION
       "A human-readable description to identify this defined
       per-hop-behavior.  Note that this is an SnmpAdminString,
       which permits UTF-8 strings.  An administratively assigned
       identifier for a template that would be unique within
       an administrative domain.  It is up to the management
       applications to agree how these are assigned within the
       administrative domain.  Once a description, such as
       'EF' is assigned, that has a certain set of parameters
       that achieve 'EF' from box to box. Management
       application code or script code can then scan
       the table to find the proper template and then
       assign it."
    ::= { diffServConfigEntry 2 }

diffServConfigOwner OBJECT-TYPE
    SYNTAX         SnmpAdminString
    MAX-ACCESS     read-create
    STATUS         current
    DESCRIPTION
       "The owner who created this entry."
    ::= { diffServConfigEntry 3 }

diffServConfigLastChange OBJECT-TYPE
    SYNTAX         DateAndTime
    MAX-ACCESS     read-only
    STATUS         current
    DESCRIPTION
       "The date and time when this entry was last changed."
    ::= { diffServConfigEntry 4 }

diffServConfigStart OBJECT-TYPE
    SYNTAX         RowPointer
    MAX-ACCESS     read-create
    STATUS         current
    DESCRIPTION
       "The pointer to a functional datapath configuration template as
       set up in the DIFFSERV-MIB.  This RowPointer should
       point to an instance of one of:
         diffServClfrEntry
         diffServMeterEntry
         diffServActionEntry
         diffServAlgDropEntry
         diffServQEntry

       A value of zeroDotZero in this attribute indicates no
       further Diffserv treatment is performed on traffic of
       this functional datapath.  This also means that the
       template described by this row is not defined.

       If the row pointed to does not exist, the treatment
       is as if this attribute contains a value of zeroDotZero."
    REFERENCE
       "Differentiated Services MIB module"
    DEFVAL { zeroDotZero }
    ::= { diffServConfigEntry 5 }

diffServConfigStorage OBJECT-TYPE
    SYNTAX         StorageType
    MAX-ACCESS     read-create
    STATUS         current
    DESCRIPTION
       "The type of storage used for this row.

       Since an entry in this table serves as a starting
       point for a configuration, it is recommended that
       all entries comprising the configuration started by
       diffServConfigStart follow the storage type of this
       entry.  Otherwise, after agent reboots a configuration
       may differ.  It may very well be that the agent is
       not capable of detecting such changes and therefore,
       the management application should verify the correct
       configuration after a reboot.  Rows with a StorageType
       of 'permanent' do not need to allow write access to
       any of the columnar objects in that row."
    DEFVAL { nonVolatile }
    ::= { diffServConfigEntry 6 }

diffServConfigStatus OBJECT-TYPE
    SYNTAX         RowStatus
    MAX-ACCESS     read-create
    STATUS         current
    DESCRIPTION
       "RowStatus object used for creation and deletion of
       rows in this table.  All writable objects in this row
       may be modified at any time."
    DEFVAL { notInService }
    ::= { diffServConfigEntry 7 }

--
-- MIB Compliance statements.
--

diffServConfigMIBCompliances
   OBJECT IDENTIFIER ::= { diffServConfigMIBConformance 1 }
diffServConfigMIBGroups
   OBJECT IDENTIFIER ::= { diffServConfigMIBConformance 2 }

diffServConfigMIBFullCompliance MODULE-COMPLIANCE
    STATUS       current
    DESCRIPTION
       "The full compliance for this MIB module.

       For this compliance level the 'diffServMIBFullCompliance'
       must be met, since this MIB module depends on it in order
       to provide the configuration entries.
       "
    MODULE  -- This module
    MANDATORY-GROUPS {  diffServConfigMIBConfigGroup }

    OBJECT diffServConfigStatus
    SYNTAX RowStatus { active(1) }
    WRITE-SYNTAX RowStatus { createAndGo(4), destroy(6) }
    DESCRIPTION
       "Support for createAndWait and notInService is not required."

    ::= { diffServConfigMIBCompliances 1 }

diffServConfigMIBConfigGroup OBJECT-GROUP
    OBJECTS {  diffServConfigDescr,
               diffServConfigOwner,
               diffServConfigLastChange,
               diffServConfigStart,
               diffServConfigStorage,
               diffServConfigStatus
    }
    STATUS current
    DESCRIPTION
       "The per-hop-behavior Group defines the MIB objects that
       describe the configuration template for the per-hop-behavior."
    ::= { diffServConfigMIBGroups 1 }
END

8. Security Considerations

   There are a number of management objects defined in this MIB module
   with a MAX-ACCESS clause of read-write and/or read-create.  Such
   objects may be considered sensitive or vulnerable in some network
   environments.  The support for SET operations in a non-secure
   environment without proper protection can have a negative effect on
   network operations.  These managed objects are:

   -  The diffServConfigDescr, diffServConfigOwner, and
      diffServConfigStatus are not security sensitive since these three
      objects do not affect any direct operational behavior of a
      diffserv capable device.

   -  Unauthorized change of the diffServConfigStart could lead to a
      different configuration, and the 'changed' configuration could
      lead to different traffic treatment for the diffserv capable
      device than desired.

   -  Unauthorized change of the diffServConfigStorage could lead to
      unknown behavior of the diffserv capable device after a reboot of
      the SNMP agent.  This may be caused by 'not having saved changes
      of the configuration' or unavailable configurations.

   In addition, the managed objects of the DIFFSERV-MIB are also
   security sensitive, since unauthorized changes may cause
   configuration changes.  For more detail, refer to [RFC3289].

   Allowing read access to objects in this MIB module is generally not
   considered sensitive, as read access only provides information that a
   template exists.  This is due to the fact that the managed objects
   that actually instantiate the template are in the DIFFSERV-MIB
   [RFC3289].  However, in environments where the template description
   (diffServConfigDescr) or owner (diffServConfigOwner) is considered
   sensitive information, appropriate access control should be exercised
   for these objects.

   SNMP versions prior to SNMPv3 did not include adequate security.
   Even if the network itself is secure (for example by using IPSec),
   there is no control as to who on the secure network is allowed to
   access and GET/SET (read/change/create/delete) the objects in this
   MIB module.

   It is RECOMMENDED that implementers consider the security features as
   provided by the SNMPv3 framework (see [RFC3410], section 8),
   including full support for the SNMPv3 cryptographic mechanisms (for
   authentication and privacy).

   Further, deployment of SNMP versions prior to SNMPv3 is NOT
   RECOMMENDED.  Instead, deployment of SNMPv3 with cryptographic
   security enabled is RECOMMENDED.  It is then a customer/operator
   responsibility to ensure that the SNMP entity giving access to an
   instance of this MIB module is properly configured to give access to
   the objects only to those principals (users) that have legitimate
   rights to GET or SET (change/create/delete) them.

9. Acknowledgments

   The editors gratefully acknowledge the significant contributions to
   this work made by several members of both the SNMPCONF and DiffServ
   working groups.

10. References

10.1. Normative References

   [RFC2578] McCloghrie, K., Perkins, D. and J. Schoenwaelder,
             "Structure of Management Information Version 2 (SMIv2)",
             STD 58, RFC 2578, April 1999.

   [RFC2579] McCloghrie, K., Perkins, D. and J. Schoenwaelder, "Textual
             Conventions for SMIv2", STD 58, RFC 2579, April 1999.

   [RFC2580] McCloghrie, K., Perkins, D. and J. Schoenwaelder,
             "Conformance Statements for SMIv2", STD 58, RFC 2580, April
             1999.

   [RFC3289] Baker, F., Chan, K. and A. Smith, "Management Information
             Base for the Differentiated Services Architecture", RFC
             3289, May 2002.

   [RFC3411] Harrington, D., Presuhn, R. and B. Wijnen, "An Architecture
             for Describing Simple Network Management Protocol (SNMP)
             Management Frameworks", STD 62, RFC 3411, December 2002.

10.2. Informative References

   [RFC3410] Case, J., Mundy, R., Partain, D. and B. Stewart,
             "Introduction and Applicability Statements for Internet-
             Standard Management Framework", RFC 3410, December 2002.

   [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, December 1998.

   [RFC2475] Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z. and
             W. Weiss, "An Architecture for Differentiated Services",
             RFC 2475, December 1998.

   [RFC3512] MacFaden, M., Partain, D., Saperia, J. and W. Tackabury,
             "Configuring Networks and Devices with Simple Network
             Management Protocol (SNMP)", RFC 3512, April 2003.

   [PMMIBDR] Waldbusser, S., Saperia, J. and T. Hongal, "Policy-based
             Management MIB", Work in Progress.

11. Editors' Addresses

   Harrie Hazewinkel
   I.Net
   via Darwin 85
   20019 - Settimo Milanese (MI)
   Italy

   EMail: harrie@inet.it

   David Partain
   Ericsson AB
   P.O. Box 1248
   SE-581 12 Linkoping
   Sweden

   EMail: David.Partain@ericsson.com

12. Full Copyright Statement

   Copyright (C) The Internet Society (2004).  This document is subject
   to the rights, licenses and restrictions contained in BCP 78 and
   except as set forth therein, the authors retain all their rights.

   This document and the information contained herein are provided on an
   "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
   OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
   ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
   INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
   INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
   WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

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Acknowledgement

Funding for the RFC Editor function is currently provided by the
Internet Society.