RFC 3318
Framework Policy Information Base
Pages: 70
Historic
Historic
Part 1 of 3 – Pages 1 to 21
Network Working Group R. Sahita, Ed. Request for Comments: 3318 S. Hahn Category: Informational Intel Labs K. Chan Nortel Networks K. McCloghrie Cisco Systems March 2003 Framework Policy Information Base Status of this Memo This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited. Copyright Notice Copyright (C) The Internet Society (2003). All Rights Reserved.Abstract
This document defines a set of PRovisioning Classes (PRCs) and textual conventions that are common to all clients that provision policy using Common Open Policy Service (COPS) protocol for Provisioning. Structure of Policy Provisioning Information (SPPI) describes a structure for specifying policy information that can then be transmitted to a network device for the purpose of configuring policy at that device. The model underlying this structure is one of well- defined (PRCs) and instances of these classes (PRIs) residing in a virtual information store called the Policy Information Base (PIB). One way to provision policy is by means of the (COPS) protocol with the extensions for provisioning. This protocol supports multiple clients, each of which may provision policy for a specific policy domain such as QoS, virtual private networks, or security. As described in COPS usage for Policy Provisioning (COPS-PR), each client supports a non-overlapping and independent set of PIB modules. However, some PRovisioning Classes are common to all subject- categories (client-types) and need to be present in each.
Table of Contents
Conventions used in this document.................................2 1. Glossary.......................................................2 2. General PIB Concepts...........................................3 2.1. Roles......................................................3 2.1.1. An Example.............................................5 2.2. Management of Role-Combinations from the PDP...............6 2.3. Updating a Request State...................................7 2.3.1 Full Request State......................................8 2.3.2 Installing PRIs in a Request............................8 2.3.3 Updating PRIs in a Request..............................8 2.3.4 Removing PRIs from a Request............................9 2.3.5 Removing EXTENDED, AUGMENTED PRIs.......................9 2.3.6 Error Handling in Request updates.......................9 2.4. Multiple PIB Instances....................................10 2.5. Reporting and Configuring of Device Capabilities..........11 2.6. Reporting of Device Limitations...........................12 3. The Framework TC PIB module...................................12 4. Summary of the Framework PIB..................................17 4.1. Base PIB classes Group....................................17 4.2. Device Capabilities group.................................19 4.3. Classifier group..........................................20 4.4. Marker group..............................................20 5. The Framework PIB Module......................................21 6. Security Considerations.......................................66 7. IANA Considerations...........................................67 8. References....................................................67 8.1 Normative References.......................................67 8.2 Informative References.....................................68 9. Acknowledgments...............................................68 10. Authors' Addresses...........................................69 11. Full Copyright Statement.....................................70 Conventions used in this document The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119].1. Glossary
PRC PRovisioning Class. A type of policy data. See [POLTERM]. PRI PRovisioning Instance. An instance of a PRC. See [POLTERM]. PIB Policy Information Base. The database of policy information. See [POLTERM] PDP Policy Decision Point. See [RAP-FRAMEWORK]. PEP Policy Enforcement Point. See [RAP-FRAMEWORK].
2. General PIB Concepts
2.1. Roles
The policy to apply to an interface may depend on many factors, such as immutable characteristics of the interface (e.g., Ethernet or frame relay), the status of the interface (e.g., half or full duplex), or user configuration (e.g., branch office or headquarters interface). Rather than specifying policies explicitly for each interface of all devices in the network, policies are specified in terms of interface functionality. To describe these functionalities of an interface, we use the concept of "Roles". A Role is simply a string that is associated with an interface. A given interface may have any number of roles simultaneously. Provisioning classes have an attribute called a "RoleCombination" which is a lexicographically ordered set of roles. Instances of a given PRovisioning Class are applied to an interface if and only if the set of roles in the role combination matches the set of the roles of the interface. Thus, roles provide a way to bind policy to interfaces without having to explicitly identify interfaces in a consistent manner across all network devices. That is, roles provide a level of indirection to the application of a set of policies to specific interfaces. This separates the policy definition from device implementation specific interface identification. Furthermore, if the same policy is being applied to several interfaces, that policy needs to be pushed to the device only once, rather than once per interface, as long as the interfaces are configured with the same role combination. We point out that, in the event that the administrator needs to have a unique policy for each interface, the administrator can configure each interface with a unique role. The PEP sends all its Capability Set Names, Role Combinations, Policy Controlled Interfaces, and their relationships to the PDP in the first COPS request (REQ) message for a handle, and whenever any updates or deletes occur. The PDP can install new instances or change existing instances of these PRIs. This operation can also occur in subsequent request messages generated in response to COPS state synchronization (SSQ) requests and local configuration changes. The comparing of roles (or role combinations) is case sensitive.
By convention, when formatting the role-combination for exchange
within a protocol message, within a PIB object's value, or as a
printed value, the set is formatted in lexicographical order of the
role's ASCII values; that is, the role that is first is formatted
first. For example, "a+b" and "b+a" are NOT different role-
combinations; rather, they are different formatting of the same
role-combination, and hence for this example:
- "a+b" is the valid formatting of that role-combination,
- "b+a" is an invalid formatting of that role-combination.
The role-combination of interfaces to which no roles have been
assigned is known as the "null" role-combination. (Note the
deliberate use of lower-case letters for "null" so that it avoids
confusion with the ASCII NULL character that has a value of zero but
a length of one.)
In an "install" or an "install-notify" class, the wildcard role-
combination "*" can be used. In addition to providing for
interface-specific roles, it also allows for other optimizations in
reducing the number of role-combinations for which a policy has to be
specified. For example:
Suppose we have three interfaces:
Roles A, B and R1 are assigned to interface I1
Roles A, B and R2 are assigned to interface I2
Roles A, B and R3 are assigned to interface I3
Then, a PRI of a fictional IfDscpAssignTable that has the following
values for its attributes:
ifDscpAssignPrid = 1
ifDscpAssignRoles = "*+A+B"
ifDscpAssignName = "4queues"
ifDscpAssignDscpMap = 1
will apply to all three interfaces, because "*" matches with R1, R2
and R3. The policies can be assigned to an interface due to more
than one wild-carded role combo matching a given interface's role
combo string. The PDP should attempt to resolve conflicts between
policies before sending policies to the PEP. In the situation where
the PDP sends multiple policies to a PEP and they do conflict, either
because of an error by the PDP or because of a device specific
conflict, the PEP MUST reject the installation of the conflicting
policies and return an error.
Formally,
- The wildcard Role is denoted by "*",
- The "*" Role is not allowed to be defined as part of the role-
combination of an interface as notified by the PEP to the PDP; it
is only allowed in policies installed/deleted via COPS-PR from the
PDP to the PEP.
- For a policy to apply to an interface when the policy's role-
combination is "*+a+b", the interface's role-combination:
- Must include "a" and "b", and
- Can include zero or more other roles.
- The wildcard character "*" is listed before the other roles as "*"
is lexicographically before "a"; however, the wildcard matches any
zero or more roles, irrespective of lexicographical order. For
example: "*+b+e+g" would match "a+b+c+e+f+g".
Note that the characters "+" and "*" MUST not be used in an
interface Role. The Framework Role PIB module in section 4 of this
document contains the Role and RoleCombination Textual Conventions.
2.1.1. An Example
The functioning of roles might be best understood by an example.
Suppose I have a device with three interfaces, with roles as follows:
IF1: "finance"
IF2: "finance"
IF3: "manager"
Suppose, I also have a PDP with two policies:
P1: Packets from finance department (role "finance") get DSCP 5
P2: Packets from managers (role "manager") get DSCP 6
To obtain policy, the PEP reports to the PDP that it has some
interfaces with role combination "finance" and some with role
combination "manager". In response, the PDP downloads policy P1
associated with role combination "finance" and downloads a second
policy P2 associated with role combination "manager".
Now suppose the finance person attached to IF2 is promoted to manager
and so the system administrator adds the role "manager" to IF2. The
PEP now reports to the PDP that it has three role combinations: some
interfaces with role combination "finance", some with role
combination "manager" and some with role combination
"finance+manager". In response, the PDP downloads an additional
third policy associated with the new role combination
"finance+manager".
How the PDP determines the policy for this new role combination is
entirely the responsibility of the PDP. It could do so
algorithmically or by rule. For example, there might be a rule that
specifies that manager policy takes preference over department
policy. Or there might be a third policy installed in the PDP as
follows:
P3: Packets from finance managers (role "finance" and role
"manager") get DSCP 7
The point here is that the PDP is required to determine what policy
applies to this new role combination and to download a third policy
to the PEP for the role combination "finance+manager", even if that
policy is the same as one already downloaded. The PEP is not
required (or allowed) to construct policy for new role combinations
from existing policy.
2.2. Management of Role-Combinations from the PDP
The PEP notifies the PDP of the Role-Combination assigned to each
interface and capability set name in a COPS configuration request
(instances of the frwkIfRoleComboTable). The first request sent to
the PDP must be a 'full state' request. A 'full state' request for a
PEP includes notify and install-notify table PRIs for the PEP which
must be interpreted as the complete state of the PEP and must not be
interpreted as updates to any previous set of PRIs sent in a previous
message. Any previous PRIs from the PEP should be discarded when a
'full state' request is received for the particular request handle.
A request is specified as a 'full state' request by setting the
frwkPibIncarnationFullState attribute in the frwkPibIncarnation PRI
sent in the request.
All existing frwkIfRoleCombo instances must be sent to the PDP in the
first configuration request for a request handle. If the Role-
Combinations are not assigned specific values, default ('null')
Role-Combinations must be sent to the PDP for all ifIndices active on
the PEP and updates must be sent every time the IfIndices are
updated. The PEP may notify the PDP of the Capability sets (if any)
via the frwkCapabilitySetTable. If the PEP does not need to notify
the PDP of capability sets, it must set the capability set name in
the frwkIfRoleComboTable instances to a zero length string.
In response to this configuration request, if applicable, the PDP may
send policies for the PEP in a solicited decision or must send a null
decision. The PEP must then send a solicited report message for the
decision.
At any later time, the PDP can update the Role-Combinations assigned to a specific interface, identified by IfIndex, or for an aggregate, identified by the capability set name, via an unsolicited decision to the PEP on any open request handle. The PDP does this by sending updated PRIs for the frwkIfRoleComboTable. When the Interface Role Combination associations are updated by the PDP, the PEP SHOULD send updated 'full state' requests for all open contexts. A context is an instantiation of the PIB module(s) namespace identified by a unique COPS handle for a particular COPS client type. This is true even if the PEP's request state changes due to an internal event or if the state is changed by the PDP. If the role-combination updates were sent by the PDP, the PEP SHOULD send these updated requests only if it can process the unsolicited decision containing the frwkIfRoleCombo PRIs successfully, and it MUST do so after sending the success report for the unsolicited decision. If the PEP failed to process the decision (i.e., the frwkIfRoleCombo PRIs), it MUST only send a failure report to the PDP. On the other hand, the PDP must not expect to receive the updated requests with the revised role-combination information until after it receives a success report for these updates from the PEP. If the PDP does not receive updated requests on some request handles, the PEP must not be sent decision updates for that frwkIfRoleCombo updates, i.e., the PDP must have the previous request state that it maintained for that request handle. Note that, any unsolicited decisions received by the PEP in the time period after it receives updates to its Role-Combination associations and before receiving solicited decisions for the updated requests it sent for all context handles, could possibly contain outdated policies corresponding to the old Role-Combination associations as notified by this PEP in a previous request state. The PDP must respond to the updated requests by solicited decisions, sending policies if applicable or null decisions. The PEP must respond to these solicited decisions with solicited reports to complete the transaction.2.3. Updating a Request State
This section describes the messages exchanged between the PEP and PDP when the PEP is updating a previously sent request for a particular COPS handle. Note that a PEP can incrementally update a request only if the frwkPibIncarnationFullState attribute is shown to be supported via the supported PRC table. If this attribute is not supported, the PDP must treat all PEP requests as the full request state.
2.3.1 Full Request State
When the PEP wants to send the entire request state to the PDP (for example, in response to a Synchronize State Request from the PDP), the PEP MUST send the incarnation instance with the frwkPibIncarnationFullState attribute set to 'true'. A PDP that receives an incarnation instance in the request message with this attribute set to 'true', must clear the request information it maintains for this request handle and re-install the information received. If this attribute is set to 'false' or if the incarnation instance is missing in the request message, the request must be interpreted as an incremental update to the previous request message.2.3.2 Installing PRIs in a Request
If the PEP wants to install additional PRIs for a request handle, the PEP MUST ensure that the frwkPibIncarnationFullState attribute is set to 'false', and the PEP MUST use new (unused in this context) InstanceIds [SPPI] for these PRIs. When a PDP receives instances with new InstanceIds for a request with the frwkPibIncarnationFullState in the incarnation instance set to 'false', or if the request has no incarnation information, it must interpret these PRIs as an incremental update to the request state and add them to the request state it maintains for this handle.2.3.3 Updating PRIs in a Request
If the PEP wants to update previously installed PRIs for a request handle, the PEP MUST ensure that the frwkPibIncarnationFullState attribute is set to 'false' for these PRIs. Note that the PEP must send the same InstanceIds for the PRIs being updated. If the PEP uses new InstanceIds, the PDP must interpret them as Install's for this request state. When a PDP receives a request with instances having InstanceIds that exist in its state for that handle with the frwkPibIncarnationFullState in the incarnation instance set to 'false' or if the request has no incarnation information, it must interpret these PRIs as an update to the PRIs in the request state it maintains for this handle.
2.3.4 Removing PRIs from a Request
If the PEP wants to remove previously installed PRIs for a request handle, the PEP MUST ensure that the frwkPibIncarnationFullState attribute is set to 'false', and MUST send the PRI bindings with the PRID set to the InstanceId of the PRI to be removed, and the length field in the EPD object header set to the header length only, effectively setting the data length to zero. Note that the PEP must send the same InstanceIds for the PRIs being removed. If the PEP sends new InstanceIds and the length field in the EPD object header is set to the header length only (implying the data length is zero), the PEP is attempting to remove an unknown/non-existent PRI. This SHOULD result in the PDP sending error PRIs in the solicited decision (see section 2.3.6 for a description of the frwkErrorTable). If the PEP sends new InstanceIds, and the length field in the EPD object header is greater than the header length only (implying the EPD object has some attributes encoded in it), the PDP will interpret this as an install of the PRI if it can decode the EPD successfully. When a PDP receives a request with instances having InstanceIds that exist in its state for that handle with the frwkPibIncarnationFullState in the incarnation instance set to 'false', or if the request has no incarnation information, and the length field in the EPD object header is set to the header length only (implying the data length is zero), it must remove these PRIs from the request state it maintains for this handle.2.3.5 Removing EXTENDED, AUGMENTED PRIs
The PEP should remove the extended/augmented PRIs when it removes the base PRIs in the same COPS message. See [SPPI] for a description of EXTENDED/AUGMENTED PRCs. A PDP that receives removes for a base PRI must implicitly remove the extensions.2.3.6 Error Handling in Request updates
If the PDP cannot process all the request installs/updates/removes in the COPS request message successfully, it MUST rollback to its previous request state and it MUST send a solicited decision to the PEP that contains frwkErrorTable instances. These instances contain an error code and a sub-code as defined in the [COPS-PR] CPERR object. For example, if the PEP tries to remove an instance that does not exist, the 'priInstanceInvalid' error code must be sent to the PEP in a frwkError PRI. The frwkError PRIs also contain the PRC and the InstanceId of the error-causing PRI. The PEP may then
examine these error PRIs and resend the modified request. Note that, until the PEP resends the request updates/removes, it will have configuration information for the last successful request state it sent to the PDP.2.4. Multiple PIB Instances
[COPS-PR] supports multiple, disjoint, independent instances of the PIB to represent multiple instances of configured policy. The intent is to allow for the pre-provisioning of policy that can then be made active by a single, short decision from the PDP. A COPS context can be defined as an independent COPS request state for a particular subject category (client-type). A context may be an outsourcing context or a configuration context. A configuration context is an instance of the PIB triggered and controlled by the PDP, which contains device setup information. This device configuration information dictates the device behavior as specified by the PDP. An outsourcing context on the other hand, is a PIB instance that is triggered from the PEP side and is a request to the PDP for action. The action requested will be interpreted in the domain of the client-type. Configuration contexts belong to a set of configuration contexts for a specific client type - out of which one configuration context may be active. However, multiple outsourcing contexts can be active simultaneously. With the [COPS-PR] protocol, each of these states is identified by a unique client handle. The creation and deletion of these PIB instances can be controlled by the PDP as described in [COPS-PR] or can be triggered by an event by the PEP. A PEP must open at least one "request-state" for configuration for a given subject-category (client type). Additional "request-states" at the PEP may be initiated by the PDP or asynchronously generated by the PEP for outsourcing due to local events, which will be fully specified by the PRID/EPD data carried in the request. The frwkPibIncarnationInCtxtSet flag defines a set of contexts out of which only one context can be active at any given time. This set is called the 'configuration contexts' set. At most, one context may be active from this 'configuration context' set at any given time. Contexts that have the frwkPibIncarnationInCtxtSet attribute set to 'true' belong to this set. Contexts that do not belong to this set have the frwkPibIncarnationInCtxtSet set to 'false' and belong to the set of 'outsourcing contexts'. Note that a PEP can have these two sets of contexts only if the frwkPibIncarnationInCtxtSet attribute is shown to be supported via the supported PRC table. If the
frwkPibIncarnationInCtxtSet is not supported, a PEP must treat all contexts as belonging to the set of 'configuration contexts' i.e., at the most one context can be active at any given time. Note that in the event that a PEP has a capability change such as a card hot swap or any other change in its notify information that may warrant a policy refresh, a subsequent complete or incremental request must be issued to the PDP containing the new/updated capabilities for all the configuration contexts. A request for re- configuration is issued for all request state configuration contexts, both for the active configuration context as well as any inactive configuration contexts. This is to ensure that when an inactive configuration context is activated, it has been pre-configured with policies compatible with the PEP's current capabilities. Although many PIB instances may be configured on a device (the maximum number of these instances being determined by the device itself), only one of the contexts from the 'configuration contexts' set can be active at any given time; the active one being selected by the PDP. The Framework PIB supports the attribute frwkPibIncarnationActive in the frwkPibIncarnationTable to allow the PDP to denote the PIB instance as being active in a COPS decision message, and similarly, to report the active state (active or not) of the PIB instance to the PDP in a COPS request message. When the PEP installs an attribute frwkPibIncarnationActive that is 'true' in one PIB instance which belongs to the 'configuration contexts' set, the PEP must ensure, re-setting the attribute if necessary, that the frwkPibIncarnationActive attribute is 'false' in all other installed contexts that belong to this set. To switch contexts, the PDP should set the frwkPibIncarnationActive attribute to 'true' in the context it wants to make the active context. The PDP should set this attribute in a context to 'false' only if it wants to send an inactive context to the PEP or deactivate the active context on the PEP. If an active context is made inactive without activating another context, the PEP must not have any policies enforced from any configuration contexts installed.2.5. Reporting and Configuring of Device Capabilities
Each network device providing policy-based services has its own inherent capabilities. These capabilities can be hardware specific, e.g., an Ethernet interface supporting input classification, or can be statically configured, e.g., supported queuing disciplines. These capabilities are organized into Capability Sets, with each Capability Set given a unique name (frwkCapabilitySetName) and associated with a set of Role Combinations. In that way, each Role Combination may be associated with a set of interfaces. These capabilities are
communicated to the PDP when policy is requested by the PEP. Knowing device capabilities, the PDP can send the PRIs relevant to the specific device, rather than sending the entire PIB. Specific capability PRCs may be defined in other PIBs. These capability instances are grouped via the frwkCapabilitySetTable. If the PEP wishes to send capability information to the PDP, the PIB must indicate which capabilities the PEP may send to the PDP by means of the 'notify' PIB-ACCESS clause as described in [SPPI]. If a PIB does not have any capabilities to communicate to the PDP, it must not send any instances for the frwkCapabilitySetTable. If in this case the frwkIfRoleCombo table is used to communicate role combinations assigned to interfaces (via IfIndex), the frwkRoleComboCapSetName attribute in the frwkIfRoleComboTable instances must be set to a zero length string.2.6. Reporting of Device Limitations
To facilitate efficient policy installation, it is important to understand a device's limitations in relation to the advertised device capabilities. Limitations may be class-based, e.g., an "install" class is supported as a "notify" or only a limited number of class instances may be created, or attribute-based. Attribute limitations, such as supporting a restricted set of enumerations or requiring related attributes to have certain values, detail implementation limitations at a fine level of granularity. A PDP can avoid certain installation issues in a proactive fashion by taking into account a device's limitations prior to policy installation rather than in a reactive mode during installation. As with device capabilities, device limitations are communicated to the PDP when policy is requested. Reported device limitations may be accompanied by guidance values that can be used by a PDP to determine acceptable values for the identified attributes.3. The Framework TC PIB module
FRAMEWORK-TC-PIB PIB-DEFINITIONS ::= BEGIN IMPORTS MODULE-IDENTITY, TEXTUAL-CONVENTION, Unsigned32, pib FROM COPS-PR-SPPI; frwkTcPib MODULE-IDENTITY SUBJECT-CATEGORIES { all } LAST-UPDATED "200302130000Z" -- 13 Feb 2003 ORGANIZATION "IETF RAP WG"
CONTACT-INFO "Keith McCloghrie
Cisco Systems, Inc.
170 West Tasman Drive,
San Jose, CA 95134-1706 USA
Phone: +1 408 526 5260
Email: kzm@cisco.com
John Seligson
Nortel Networks, Inc.
4401 Great America Parkway
Santa Clara, CA 95054 USA
Phone: +1 408 495 2992
Email: jseligso@nortelnetworks.com
Ravi Sahita
Intel Labs.
2111 NE 25th Ave.
Hillsboro, OR 97124 USA
Phone: +1 503 712 1554
Email: ravi.sahita@intel.com
RAP WG Mailing list: rap@ops.ietf.org "
DESCRIPTION
"The PIB module containing the Role and RoleCombination
Textual Conventions and other generic TCs.
Copyright (C) The Internet Society (2003). This version of
this PIB module is part of RFC 3318; see the RFC itself for
full legal notices."
REVISION "200302130000Z" -- 13 Feb 2003
DESCRIPTION "Initial version, published in RFC 3318."
::= { pib 3 }
Role ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"A role represents a functionality characteristic or
capability of a resource to which policies are applied.
Examples of roles include Backbone_interface,
Frame_Relay_interface, BGP-capable-router, web-server,
firewall, etc.
The only valid character set is US-ASCII. Valid characters
are a-z, A-Z, 0-9, period, hyphen and underscore. A role
must always start with a letter (a-z or A-Z). A role must
not contain the US-ASCII characters '*' or '+' since they
have special meaning associated with them, explained in the
RoleCombination TEXTUAL CONVENTION."
SYNTAX OCTET STRING (SIZE (1..31))
RoleCombination ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"An octet string containing concatenated Roles. For the
format specification of roles, refer to the 'Role' TEXTUAL-
CONVENTION. A valid Role Combination must be formed by a set
of valid Roles, concatenated by the US-ASCII character '+',
where the roles are in lexicographic order from minimum to
maximum. For example, 'a+b' and 'b+a' are NOT different
role-combinations; rather, they are different formatting of
the same (one) role-combination.
Notice the roles within a role-combination are in
Lexicographic order from minimum to maximum, hence, we
declare:
'a+b' is the valid formatting of the role-combination,
'b+a' is an invalid formatting of the role-combination.
Notice the need of zero-length role-combination as the role-
combination of interfaces to which no roles have been
assigned. This role-combination is also known as the 'null'
role-combination. (Note the deliberate use of lower case
letters to avoid confusion with the US-ASCII NULL character
which has a value of zero but length of one.)
The US-ASCII character '*' is used to specify a wild carded
Role Combination. '*' must not be used to wildcard Roles.
Hence, we declare:
'*+a+b' is a valid wild carded Role Combination.
'eth*+a+b' is not a valid wild carded Role Combination.
Note that since Roles are lexicographically listed in a Role
Combination, the following is an invalid role combination,
since '*' is lexicographically before 'a': 'a+b+*'."
SYNTAX OCTET STRING (SIZE (0..255))
PrcIdentifierOid ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"An OID that identifies a PRC. The value MUST be an OID
assigned to a PRC's entry definition. The Entry definition
of a PRC has an OID value XxxTable.1 where XxxTable is the
OID assigned to the PRC table object.
An attribute with this syntax MUST specify a PRC, which is
defined in the PIB module(s) registered in the context of
the client-type used.
An attribute with this syntax cannot have the value 0.0
(zeroDotZero). If the attribute using this syntax can be set
to 0.0 use the PrcIdentifierOidOrZero TEXTUAL-CONVENTION
which makes such use explicit."
SYNTAX OBJECT IDENTIFIER
PrcIdentifierOidOrZero ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"An OID that identifies a PRC or zeroDotZero (0.0). The
value MUST be an OID assigned to a PRC's entry definition or
0.0 (zeroDotZero). The Entry definition of a PRC has an OID
value XxxTable.1 where XxxTable is the OID assigned to the
PRC table object.
An attribute with this syntax can have the value 0.0
(zeroDotZero) to indicate that it currently does not
identify a PRC."
SYNTAX OBJECT IDENTIFIER
AttrIdentifier ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"A Unsigned32 value that identifies an attribute in a PRC by
its sub-id. The sub-id is the OID assigned to this attribute
in the PRC definition.
A AttrIdentifier value is always interpreted within the
context of an attribute of type PrcIdentifierOid or
PrcIdentifierOidOrZero. The PrcIdentifierOid (or
PrcIdentifierOidOrZero) object which defines the context
must be registered immediately before the object which uses
the AttrIdentifier textual convention. If the context
defining attribute is of type PrcIdentifierOidOrZero and has
the value 0.0, then in that case this attribute value has no
meaning.
An attribute with this syntax MUST specify a sub-id which
MUST be defined in the PRC identified (if any) in the
PrcIdentifierOid (or PrcIdentifierOidOrZero) attribute. The
PrcIdentifierOid (orZero) and the AttrIdentifier attributes
together identify a particular attribute in a particular
PRC.
An attribute with this syntax cannot have the value 0
(zero). If the attribute using this syntax can be set
to 0 use the AttrIdentifierOrZero TEXTUAL-CONVENTION which
makes that explicit."
SYNTAX Unsigned32 (1..4294967295)
AttrIdentifierOrZero ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"A Unsigned32 value that identifies an attribute in a PRC by
its sub-id or has the value 0 (zero). The sub-id if non-
zero, is the OID assigned to this attribute in the PRC
definition.
An AttrIdentifierOrZero value is always interpreted within
the context of an attribute of type PrcIdentifierOid or
PrcIdentifierOidOrZero. The PrcIdentifierOid (or
PrcIdentifierOidOrZero) object that defines the context must
be registered immediately before the object which uses the
AttrIdentifierOrZero textual convention. If the context
defining attribute is of type PrcIdentifierOidOrZero and has
the value 0.0, then in that case this attribute value has no
meaning.
An attribute with this syntax can have the value 0 (zero) to
indicate that it currently does not identify a PRC
attribute. If it has a non-zero value, the
PrcIdentifierOid (orZero) and the AttrIdentifierOrZero
attributes together identify a particular attribute in a
particular PRC."
SYNTAX Unsigned32
AttrIdentifierOid ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"An OID that identifies an attribute in a PRC. The value
MUST be an OID assigned to a PRC's attribute definition. The
last sub-id is the sub-id of the attribute as it is
defined in the PRC entry definition. The prefix OID (after
dropping the last sub-id) is the OID assigned to the Entry
object of a defined PRC. The Entry definition of a PRC has
an OID value XxxTable.1 where XxxTable is the OID assigned
to the PRC Table object.
An attribute with this syntax MUST not have the value 0.0
(zeroDotZero). If 0.0 is a valid value, the TEXTUAL
CONVENTION AttrIdentifierOidOrZero must be used which makes
such use explicit."
SYNTAX OBJECT IDENTIFIER
AttrIdentifierOidOrZero ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"An OID that identifies an attribute in a PRC or has a value
0.0 (zeroDotZero). The value MUST be an OID assigned to a
PRC's attribute definition or the value 0.0.
If not 0.0, the last sub-id MUST be the sub-id of the
attribute as it is defined in the PRC Entry object
definition. The prefix OID (after dropping the last sub-id)
is the OID assigned to the Entry object of a defined PRC.
The Entry definition of a PRC has an OID value XxxTable.1
Where, XxxTable is the OID assigned to the PRC Table
object.
An attribute with this syntax can have the value 0.0
(zeroDotZero) to indicate that it currently does not
identify a PRC's attribute."
SYNTAX OBJECT IDENTIFIER
ClientType ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"An Unsigned32 value that identifies a COPS Client-type. An
attribute with this syntax must be set to zero if it does
not specify a COPS client-type for the PRI."
REFERENCE
"The COPS (Common Open Policy Service) Protocol, RFC 2748."
SYNTAX Unsigned32 (0..65535)
ClientHandle ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"An octet string that identifies a COPS Client handle. A
zero length value implies the attribute does not specify a
valid client handle."
REFERENCE
"The COPS (Common Open Policy Service) Protocol, RFC 2748."
SYNTAX OCTET STRING (SIZE(0..65535))
END
4. Summary of the Framework PIB
The Framework PIB defines four groups of PRCs:4.1. Base PIB classes Group
This contains PRCs intended to describe the PRCs supported by the PEP, PRC and/or attribute limitations and its current configuration. PRC Support Table As the technology evolves, we expect devices to be enhanced with new PIBs, existing PIBs to add new PRCs and existing PRCs to be augmented or extended with new attributes. Also, it is likely that some existing PRCs or individual attributes of PRCs will be deprecated. The PRC Support Table describes the PRCs that the device supports as well as the individual attributes of each PRC. Using this information the PDP can potentially tailor the policy to more closely match the capabilities of the device. The PRC Support Table instances are specific to the particular Subject Category (Client-Type). That is, the PRC Support Table for Subject Category 'A' will not include instances for classes supported by the Subject Category 'B'. Note that the COPS client-type [COPS] used for Framework PIB PRIs sent/received over COPS-PR MUST be the unique SUBJECT- CATEGORY number assigned for the area of policy being managed (e.g., QoS, Security etc). The PEP MUST ignore the attributes that it reports as not Supported in the decision from the PDP. The PEP SHOULD not send duplicate PRC support instances in a COPS Request and the PDP MUST ignore duplicate instances and MUST use the first instance received for a supported PRC in a COPS Request. PIB Incarnation Table This PRC contains exactly one row (corresponding to one PRI) per context. It identifies the PDP that was the last to download policy into the device and also contains an identifier to identify the version of the policy currently downloaded. This identifier, both its syntax and value, is meaningful only to the PDPs. It is intended to be a mechanism whereby a PDP, when accepting a connection from a PEP, can easily identify a known incarnation of policy. This PRC defines a flag via which the installed contexts are divided into a set of contexts ('configuration contexts') out of which only one context is active and a the remaining contexts form a set of 'outsourcing contexts' which are all active. The incarnation PRC also defines an attribute to indicate which configuration context is
the active one at the present time in the 'configuration
contexts' set. The incarnation instance is specific to the
particular Subject Category (Client-Type).
Component Limitations Table
Some devices may not be able to implement the full range of
values for all attributes. In principle, each PRC supports a
set of errors that the PEP can report to the PDP in the event
that the specified policy is not implementable. It may be
preferable for the PDP to be informed of the device limitations
before actually attempting to install policy, and while the
error can indicate that a particular attribute value is
unacceptable to the PEP, this does not help the PDP ascertain
which values would be acceptable. To alleviate these
limitations, the PEP can report some limitations of attribute
values and/or classes and possibly guidance values for the
attribute in the Component Limitations Table
Device Identification Table
This PRC contains a single PRI that contains device-specific
information that is used to facilitate efficient policy
installation by a PDP. The instance of this PRC is reported to
the PDP in a COPS request message so that the PDP can take into
account certain device characteristics during policy
installation.
4.2. Device Capabilities group
This group contains the PRCs that describe the characteristics of
interfaces of the device and the Role Combinations assigned to them.
Capabilities Set Table
The capabilities the PEP supports are described by rows in this
PRC (frwkCapabilitySetTable). Each row, or instance of this
class, associates a unique capability name with a set of
capabilities that an entity on the PEP may support. The unique
name is used to form a set of capabilities that the name
represents. The capability references can specify instances in
relevant capability tables in any PIB. The PEP notifies the
PDP of these capability sets and then the PDP configures the
interfaces, per role combination. The unique name
(frwkCapabilitySetName) is not to be confused with the IfType
object in the Interfaces Group MIB [RFC2863].
Interface and Role Combination Table
The Capabilities Set Table (explained above) describes the
entities on the PEP (for example, interfaces) by their
capabilities, by assigning the capability sets a unique name
(frwkCapabilitySetName). It is possible to tailor the behavior
of interfaces by assigning specific role-combinations to the
capability sets. This allows interfaces with the same
capability sets to be assigned different policies, based on the
current roles assigned to them. At the PDP, configuration is
done in terms of these interface capability set names and the
role-combinations assigned to them. Thus, each row of this
class is a <Interface Index, interface capability set name,
Role Combo> tuple, that indicates the roles that have been
assigned to a particular capability set (as identified by
frwkRoleComboCapSetName) and to a particular interface. Note
that the uniqueness criteria for this PRC has all the
attributes, thus a frwkRoleComboCapSetName may have multiple
role-combinations that it is associated with. Via the IfIndex,
this PRC answers the questions of 'which interfaces have a
specific role combination?' and 'what role combination a
specific interface is a part of?'.
4.3. Classifier group
This group contains the IP, IEEE 802 and Internal Label Classifier
elements. The set of tables consist of a Base Filter table that
contains the Index InstanceId and the Negation flag for the filter.
This frwkBaseFilterTable is extended to form the IP Filter table, the
802 Filter table [802] and the Internal Label table. Filters may
also be defined outside this document and used to extend the Base
Filter table.
The Extended classes do not have a separate Index value. Instances of
the extended classes have the same indices as their base class
instance. Inheritance is achieved using the EXTENDS keyword as
defined in [SPPI].
4.4. Marker group
This group contains the 802 marker and internal label marker PRCs.
The 802 marker may be applied to mark 802 packets with the required
VLAN Id and/or priority value. The Internal Label marker is applied
to traffic in order to label it with a network device specific label.
Such a label is used to assist the differentiation of an input flow
after it has been aggregated with other flows. The label is
implementation specific and may be used for other policy related functions like flow accounting purposes and/or other data path treatments.
(page 21 continued on part 2)