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
Copyright (C) The Internet Society (2004). All Rights Reserved.
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.
Hazewinkel & Partain Standards Track [Page 1]RFC 3747 Differentiated Services Configuration MIB April 2004
Table of Contents
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
Hazewinkel & Partain Standards Track [Page 2]RFC 3747 Differentiated Services Configuration MIB April 2004
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
Hazewinkel & Partain Standards Track [Page 3]
RFC 3747 Differentiated Services Configuration MIB April 2004
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
Hazewinkel & Partain Standards Track [Page 4]RFC 3747 Differentiated Services Configuration MIB April 2004
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.
Hazewinkel & Partain Standards Track [Page 5]
RFC 3747 Differentiated Services Configuration MIB April 2004
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.
Hazewinkel & Partain Standards Track [Page 6]
RFC 3747 Differentiated Services Configuration MIB April 2004
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.
Hazewinkel & Partain Standards Track [Page 7]RFC 3747 Differentiated Services Configuration MIB April 2004
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 |
+-----------------+-----------------------------+--
Hazewinkel & Partain Standards Track [Page 8]RFC 3747 Differentiated Services Configuration MIB April 2004
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
Hazewinkel & Partain Standards Track [Page 9]
RFC 3747 Differentiated Services Configuration MIB April 2004
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 |
+-------+--------------------------+-----------------------+--
Hazewinkel & Partain Standards Track [Page 10]
RFC 3747 Differentiated Services Configuration MIB April 2004
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") )
Hazewinkel & Partain Standards Track [Page 11]RFC 3747 Differentiated Services Configuration MIB April 2004
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 |
+-----------------+-----------------------------+--
Hazewinkel & Partain Standards Track [Page 12]RFC 3747 Differentiated Services Configuration MIB April 2004
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 |
+-------+----------------------+----------------------------+--
Hazewinkel & Partain Standards Track [Page 13]
RFC 3747 Differentiated Services Configuration MIB April 2004
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".
Hazewinkel & Partain Standards Track [Page 14]
RFC 3747 Differentiated Services Configuration MIB April 2004
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]
Hazewinkel & Partain Standards Track [Page 15]RFC 3747 Differentiated Services Configuration MIB April 2004
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
--
Hazewinkel & Partain Standards Track [Page 16]RFC 3747 Differentiated Services Configuration MIB April 2004
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
Hazewinkel & Partain Standards Track [Page 17]RFC 3747 Differentiated Services Configuration MIB April 2004
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
Hazewinkel & Partain Standards Track [Page 18]RFC 3747 Differentiated Services Configuration MIB April 2004
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.
--
Hazewinkel & Partain Standards Track [Page 19]RFC 3747 Differentiated Services Configuration MIB April 2004
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:
Hazewinkel & Partain Standards Track [Page 20]RFC 3747 Differentiated Services Configuration MIB April 2004
- 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.
Hazewinkel & Partain Standards Track [Page 21]RFC 3747 Differentiated Services Configuration MIB April 2004
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.
Hazewinkel & Partain Standards Track [Page 22]RFC 3747 Differentiated Services Configuration MIB April 2004
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
Hazewinkel & Partain Standards Track [Page 23]RFC 3747 Differentiated Services Configuration MIB April 2004
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.
Intellectual Property
The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at ietf-
ipr@ietf.org.
Acknowledgement
Funding for the RFC Editor function is currently provided by the
Internet Society.
Hazewinkel & Partain Standards Track [Page 24]
