draft-ietf-rap-cops-ds-00.txt   draft-ietf-rap-cops-ds-01.txt 
COPS Usage for Differentiated Services August 1998 COPS Usage for Differentiated Services December 1998
Network Working Group Francis Reichmeyer Network Working Group Francis Reichmeyer
Internet Draft Kwok Chan Internet Draft Kwok Chan
Draft-ietf-RAP-COPS-DS-00.txt Bay Networks, Inc. draft-ietf-rap-cops-ds-01.txt Bay Networks, Inc.
Expiration Date: January 1999 David Durham Expiration Date: May 1999 David Durham
Raj Yavatkar Raj Yavatkar
Intel Intel
Silvano Gai Silvano Gai
Keith McCloghrie Keith McCloghrie
Cisco Systems, Inc. Cisco Systems, Inc.
Shai Herzog Shai Herzog
IPHighway IPHighway
August 1998 December 1998
COPS Usage for Differentiated Services COPS Usage for Differentiated Services
Status of this Memo Status of this Memo
This document is an Internet-Draft. Internet-Drafts are working This document is an Internet-Draft. Internet-Drafts are working
documents of the Internet Engineering Task Force (IETF), its areas, documents of the Internet Engineering Task Force (IETF), its areas,
and its working groups. Note that other groups may also distribute and its working groups. Note that other groups may also distribute
working documents as Internet-Drafts. working documents as Internet-Drafts.
skipping to change at line 46 skipping to change at page 2, line 5
Abstract Abstract
There is a clear need for relatively simple and coarse methods of There is a clear need for relatively simple and coarse methods of
providing differentiated classes of service for Internet traffic, to providing differentiated classes of service for Internet traffic, to
support various types of services, and specific business support various types of services, and specific business
requirements. The IETF has chartered the Differentiated Service WG to requirements. The IETF has chartered the Differentiated Service WG to
define the differentiated services architecture and a common language define the differentiated services architecture and a common language
for differentiated services. for differentiated services.
Reichmeyer, Ho Chan, Durham, Gai, McCloghrie [Page COPS Usage for Differentiated Services December 1998
1]
COPS Usage for Differentiated Services August 1998
In parallel, the IETF RSVP Admission Policy (RAP) WG has defined the In parallel, the IETF RSVP Admission Policy (RAP) WG has defined the
COPS (Common Open Policy Service) protocol [COPS]. COPS (Common Open Policy Service) protocol [COPS].
This document describes enhancements to the Common Open Policy This document describes enhancements to the Common Open Policy
Service (COPS) protocol to support policy services in a Service (COPS) protocol to support policy services in a
Differentiated Services (diff serv) environment. Further Differentiated Services (DiffServ) environment. Further modifications
modifications to COPS for diff serv may be proposed in the future, to COPS for DiffServ may be proposed in the future, but what is
but what is presented here is thought to be the minimum necessary presented here is thought to be the minimum necessary additions.
additions.
Table of contents Table of contents
1. Terminology ......................................................3 1. Terminology ......................................................3
2. Introduction ..........................Error! Bookmark not defined. 2. Introduction .....................................................4
2.1 Basic Model...................................................6 2.1 Basic Model...................................................6
3. The definition of the Policy Tree ................................7 2.2 Interaction between the PDP and the PEP.......................8
3.1 Description of the Policy Tree................................8 3. The definition of the Policy Tree ................................8
3.2 Operations Supported On a PI..................................8 3.1 Description of the Policy Tree................................9
3.3 An example of a PIB...........................................8 3.2 Operations Supported On a PRI................................10
4. COPS Diff Serv Client Data ......................................10 3.3 PIB general information......................................10
4.1 Policy Identifier (PID)......................................11 3.4 An example of a PIB..........................................10
4.2 XDR Encoded Policy Instance Data (XPD).......................11 4. COPS DiffServ Client Data .......................................13
4.3 Diff Serv Decision Data......................................12 4.1 Policy Identifier (PRID).....................................13
4.4 Diff Serv Request Data.......................................12 4.2 BER encoded Policy instance Data (BPD).......................14
4.5 Diff Serv Report Data........................................12 4.3 DiffServ Decision Data.......................................14
4.5.1 Commit Data .............................................13 4.4 DiffServ Request Data........................................15
4.5.2 No Commit Data ..........................................13 4.5 DiffServ Report Data.........................................15
4.5.3 Accounting Data .........................................13 4.5.1 Successfully Installed/Removed Data .....................15
5. Message Content .................................................13 4.5.2 Unsuccessfully Installed/Removed Data ...................15
5.1 Request (REQ) PEP -> PDP...................................13 4.5.3 Accounting Data .........................................16
5.2 Decision (DEC) PDP -> PEP..................................14 5. Message Content .................................................16
5.3 Report State (RPT) PEP -> PDP..............................15 5.1 Request (REQ) PEP -> PDP...................................16
6. Common Operation ................................................15 5.2 Decision (DEC) PDP -> PEP..................................17
7. Fault Tolerance .................................................17 5.3 Report State (RPT) PEP -> PDP..............................18
8. Security ........................................................17 6. Common Operation ................................................18
9. References ......................................................17 7. Fault Tolerance .................................................20
10. Author Information .............................................18 8. Security ........................................................21
9. References ......................................................21
10. Author Information .............................................22
Reichmeyer, Ho Chan, Durham, Gai, McCloghrie [Page COPS Usage for Differentiated Services December 1998
2]
COPS Usage for Differentiated Services August 1998
1. Terminology 1. Terminology
o ACL: Access Control List. o ACL: Access Control List.
o ClientSI: Client Specific Information Object.
o COPS (Common Open Policy Service): client/server model for o COPS (Common Open Policy Service): client/server model for
supporting policy control [COPS]; supporting policy control [COPS];
o Instance Identifier: one or more of the PC attributes the values of
which are used as part of the identification of a PI.
o Object: this term is used in the same sense as in COPS o Object: this term is used in the same sense as in COPS
specification. An object is identified by its C-num and C-type. specification. An object is identified by its C-num and C-type.
o PC (Policy Class): a type of policy data item. In object oriented
terminology this is equivalent to a class. It inherits from PC. A
PC defines a vector of attributes. Each attribute has a syntax type
that is either primitive or refined. It also overrides the READ and
WRITE methods and defines new error sub-codes.
o PI (Policy Instance): an instance of a PC. Potentially there are
multiple instances of the same PC. The value of a PI consist of a
vector of values, one value for each attribute in the PC's vector
of attributes.
o PDP (Policy Decision Point): a network entity where policy o PDP (Policy Decision Point): a network entity where policy
decisions are made decisions are made.
o PEP (Policy Enforcement Point): network device where policy o PEP (Policy Enforcement Point): network device where policy
decisions are enforced. decisions are enforced.
o Policy Rule: policy information specified by the PDP to be enforced
at the PEP.
o PRC (Policy Rule Class): a type of policy rule data item. In object
oriented terminology this is equivalent to a class. It inherits
from PRC. A PRC defines a vector of attributes. Each attribute has
a syntax type that is either primitive or refined. It also
overrides the READ and WRITE methods and defines new error sub-
codes.
o PRI (Policy Rule Instance): an instance of a PRC. Potentially there
are multiple instances of the same PRC. The value of a PRI consist
of a vector of values, one value for each attribute in the PRC's
vector of attributes.
o PII (Policy Instance Identifier): one or more of the PRC attributes
the values of which are used as part of the identification of a
PRI.
o PIB (Policy Information Base): policy objects are accessed via a o PIB (Policy Information Base): policy objects are accessed via a
virtual information store, termed the Policy Information Base or virtual information store, termed the Policy Information Base or
PIB. Objects in the PIB are defined using Abstract Syntax Notation PIB. Objects in the PIB are defined using a subset of Abstract
One (ASN.1) [ASN1]. Syntax Notation One (ASN.1) [ASN1].
o PID (Policy IDentifier): the name which identifies a particular PI o PRID (Policy Rule IDentifier): the name which identifies a
or PC. It has a hierarchical structure of the form 1.3.4.2.7, where particular PRI or PRC. It has a hierarchical structure of the form
the first part identifies the PC (i.e., 1.3.4) and the last part is 1.3.4.2.7, where the first part identifies the PRC (i.e., 1.3.4)
the value of the PII (Policy Instance Identifier), which identifies and the last part is the value of the PII (Policy Instance
the instance (i.e. 2.7). The PII is null in the case of a PC. Identifier), which identifies the instance (i.e. 2.7). The PII is
o XPD: XDR Encoded Policy Instance Data. COPS Usage for Differentiated Services December 1998
null in the case of a PRC. PRIDs are represented as a BER encoded
oids (Object Identifiers).
o BPD: BER (ASN.1 [ASN1] Basic Encoding Rule [BER]) encoded Policy
Instance Data.
2. Introduction 2. Introduction
The Common Open Policy Service (COPS) protocol is a query response The Common Open Policy Service (COPS) protocol is a query response
protocol used to exchange policy information between a network policy protocol used to exchange policy information between a network policy
Reichmeyer, Ho Chan, Durham, Gai, McCloghrie [Page
3]
COPS Usage for Differentiated Services August 1998
server and a set of clients [COPS]. COPS is being developed within server and a set of clients [COPS]. COPS is being developed within
the RSVP Admission Policy Working Group (RAP WG) of the IETF, the RSVP Admission Policy Working Group (RAP WG) of the IETF,
primarily for use as a mechanism for providing policy-based admission primarily for use as a mechanism for providing policy-based admission
control over requests for network resources [RAP]. control over requests for network resources [RAP].
The underlying assumption in the RAP framework is that applications The underlying assumption in the RAP framework is that applications
or endsystems use the RSVP [RSVP] signaling protocol to communicate or endsystems use the RSVP [RSVP] signaling protocol to communicate
Integrated Services (int serv) reservation requests to the network Integrated Services (IntServ) reservation requests to the network
nodes along the path of a flow. These reservation requests carry nodes along the path of a flow. These reservation requests carry
necessary flow specifications and requests for a flow to receive one necessary flow specifications and requests for a flow to receive one
of the defined Integrated Services, Controlled Load or Guaranteed. In of the defined Integrated Services, Controlled Load or Guaranteed. In
the int serv model, the RSVP messages themselves contain all the the IntServ model, the RSVP messages themselves contain all the
necessary information needed at the networking device to classify and necessary information needed at the networking device to classify and
service the flow [RSVP]. This information includes the session service the flow [RSVP]. This information includes the session
identifier (source and destination addresses, port numbers, and identifier (source and destination addresses, port numbers, and
transmission protocol), flowspec token bucket parameters, and transmission protocol), flowspec token bucket parameters, and
requested service. requested service.
As shown I Figure 1, the network device contacts a policy decision
point (PDP) to make the policy-based admission control decision.
Then, the policy server (PDP) is simply required to return a
Decision, such as "accept" and the network device acts as a policy
enforcement point (PEP) and uses the session information and intserv
srvice parameters to classify and service the packets belonging to
the flow.
(router, switch) policy server Edge Device Policy Server
+--------------+ +-----------+
| | | |
| | COPS | |
| +-----+ | REQ() | +-----+ |
RSVP | | |----|----------|->| | |
--------|-->| PEP | | | | PDP | |
| | |<---|----------|--| | |
| +-----+ | COPS | +-----+ |
| | DEC() | |
+--------------+ +-----------+
. Figure 1: COPS with RSVP/IntServ
_ ---------------- ________ --------______
| | | | ______
.
| Network Node | | |
.
| ----- ___ | | |
| | | | | |
.
| | PEP |<-----|------->| PDP |
.
| |_____| | |_____ |
.
| ----- | | |
.
|________________| | |
---------------- --------
Figure 1: Under the RAP framework, network elements such as a As shown in Figure 1, the network device contacts a Policy Decision
router or a switch contact the PDP for policy-based admission control Point (PDP) to make the policy-based admission control decision. The
Reichmeyer, Ho Chan, Durham, Gai, McCloghrie [Page COPS Usage for Differentiated Services December 1998
4]
COPS Usage for Differentiated Services August 1998
when a resource reservation request is received. PDP is simply required to return a Decision, such as "accept" and the
network device acts as a Policy Enforcement Point (PEP) and uses the
session information and IntServ service parameters to classify and
service the packets belonging to the flow.
Providing policy services in a diff serv environment requires some Providing policy services in a DiffServ environment requires some
different assumptions about the admission control mechanisms used in different assumptions about the admission control mechanisms used in
the network. First, there may be no explicit signaling from sources the network. First, there might be no explicit dynamic signaling from
of traffic requesting a particular service as in the case of an sources of traffic requesting a particular service, as in the case of
intserv network. Second, requests for allocation of resources to an IntServ network. Network resources are provisioned based on static
differentiated services may arrive at the policy server from entities SLAs (Service Level Agreements) at network boundaries. Second, where
other than a PEP. Examples of such sources include attached users requests for allocation of resources to differentiated services are
requesting network services via a web interface into a central used, they may arrive at the PDP from network entities other than the
management application, or H.323 servers requesting resources on PEP. Examples of such sources include attached users requesting
behalf of a user for a video conferencing application. Requests of network services via a web interface into a central management
this sort require some policy decision to be made to ensure the application, or H.323 gatekeeper requesting resources on behalf of a
requesting user/application has permission to use the requested user for a video conferencing application, as shown in Figure 2.
services and that the resources are available. Once the decision is
made, the PDP must configure one or more PEPs to provision necessary +----------+
resources for services requested. In addition, the PDP may also pass Edge Device Policy Server | H.323 |
to the PEP provisioning decisions about resources related to flows of +--------------+ +-----------+ |Gatekeeper|
a more static nature, such as long-term SLAs established across | | | | | |
boundaries of adjacent ISP networks. | | | | +----------+
| ----- | COPS | ----- | |
| | | | DECs() | | | | |
| | PEP |<---|----------|--| PDP |<----------+
| | | | | | | | Service
| ----- | | ----- | Request
| | | |
+--------------+ +-----------+
Figure 2: COPS Example with DiffServ
Requests of this sort still require some policy decision to be made
to ensure the requesting user/application has permission to use the
requested services and that the resources are available. Once the
decision is made, the PDP must configure one or more PEPs to allocate
necessary resources for services requested. In addition, the PDP may
also pass to the PEP provisioning decisions about resources related
to flows of a more static nature, such as long-term SLAs established
across boundaries of adjacent ISP networks.
In summary, the interaction between the PDP and PEP is different in In summary, the interaction between the PDP and PEP is different in
at least two respects from that in the case of the intserv at least two respects from that in the case of the IntServ
environment. First, the resource provisioning requests may originate environment. First, the resource provisioning requests may originate
COPS Usage for Differentiated Services December 1998
at places other than a PEP. Second, once the PDP makes a policy at places other than a PEP. Second, once the PDP makes a policy
decision to allocate resources for a service class or a flow decision to allocate resources for a service class or a flow
aggregate, it must pass on the sufficient information (such as packet aggregate, it must pass sufficient information (such as packet
classification filters, traffic shaper parameters) to the PEPs so classification filters, traffic shaper parameters) in the decision
that PEPs can implement policy decisions. This draft describes the message to the PEPs so that PEPs can enforce policy decisions. This
usage of the COPS protocol for communicating this information between draft describes the usage of the COPS protocol for communicating this
diff serv clients (PEPs) and the policy servers. information between DiffServ clients (PEPs) and the policy servers
(PDPs).
Reichmeyer, Ho Chan, Durham, Gai, McCloghrie [Page
5]
COPS Usage for Differentiated Services August 1998
2.1 Basic Model 2.1 Basic Model
Figure 2 shows a sample network configuration for a diffserv Figure 2 shows a sample network configuration for a DiffServ
environment. Edge routers and boundary routers are located at the environment. Edge routers and boundary routers are located at the
boundary of diffserv domains as described in [draft-nichols-diff- boundary of DiffServ domains as described in [Nichols]. The BB/PS is
serv-arch-00.txt]. The BB is responsible for admission control responsible for admission control functions and resource
functions and resource provisioning. In the COPS model, the PDP is provisioning.
part of the bandwidth broker that manages resources within a diffserv
domain. Both edge routers and boundary routers act as PEPs and
communicate with BBs using COPS for exchange of policy information.
The internal organization of the BB and policy functionality may
vary: the policy server and BB may be separate entities in which case
the BB, upon receiving COPS messages from the PEP, consults the
policy server to make its decision.
---- ---- +-----+ +-----+
| BB | | BB | | BB/ | | BB/ |
| | | | | PS | | PS |
_---- ---- +-----+ +-----+
^ ^ \ |
| / | /
| / | /
| |
.
/ Stub \ / Transit \ / Stub \ / Stub \ / Transit \ / Stub \
.
/ Network \ / Network \ / Network \ / Network \ / Network \ / Network \
|---| | |---| |---| |---| |---| | |---| +---+ | +---\ /---+ +---\ /---+ | +---+
|Tx |-| |ER1|---|BR1| |BR2|---|ER2| |-|Rx | |Tx |-| |ER1|---|BR1| |BR2|---|ER2| |-|Rx |
|---| | |-- | |---| |---| |---| | |---| +---+ | +---/ \---+ ---/ \---+ | +---+
\ / \ / \ / \ / \ / \ /
\ / \ / \ / \ / \ / \ /
Figure 2: A sample Network Configuration in which Figure 3: Sample DiffServ Network Configuration
Edge Routers (ER) and Boundary routers (BR) in the stub and transit
networks communicate with the corresponding bandwidth brokers in
their domain.
To allow for use of COPS for diff-serv specific communication and to In the COPS model, the PDP is part of the bandwidth broker/policy
distinuish diff-serv specific communication from other uses of COPS, server that manages policy information and resources within a
we have added a new client type to COPS (client type = DiffServ DiffServ domain. Both edge routers and boundary routers act as PEPs
client). In an environment where a stub network uses intserv/RSVP and communicate with BB/PS using COPS for exchange of policy
signaling for admission control and uses diffserv-based policy server information. The internal organization of the bandwidth broker
for managing resources to a transit network, use of two different functionality and policy functionality may vary and the policy server
and BB may be separate entities. In that case, either the BB or the
PS may communicate with the edge devices. The BB, upon receiving COPS
messages from the PEP, would consult the policy server to make its
final admission control decision. Similarly, if the PS receives COPS
Reichmeyer, Ho Chan, Durham, Gai, McCloghrie [Page COPS Usage for Differentiated Services December 1998
6]
COPS Usage for Differentiated Services August 1998
client types (RSVP vs diffserv) may require a method that correlates messages directly from PEP, the PS would consult the BB to verify
the two admission control decision. The issue of combining int serv available resources before making a final admission control decision.
and diff serv to provide an end-to-end QoS solution is currently
being studied [E2E]. Also, the RSVP WG is currently planning on To allow for use of COPS for DiffServ specific communication and to
addressing the use of RSVP within the differentiated services QoS distinguish DiffServ usage from other uses of COPS, we have added a
model. new client type to COPS (client type = DiffServ client). It is
possible for an edge device to contain both a COPS-DS and a COPS-RSVP
client. Each COPS clients can communicate with different PDPs, or
they can connect to the same PDP which supports both client types, as
shown in Figure 4.
Edge Device
+-----------------+
| | PS/BB
| +---------+ | +-------------+
| | | | | |
RSVP | |COPS-RSVP| | COPS-RSVP | +-----+ |
<-------|-->| Client |<--|-----------|-->| | |
| | | | | | | |
| |---------| | | | PDP | |
| | | | | | | |
| |COPS-DS |<--|-----------|-->| | |
| | Client | | COPS-DS | +-----+ |
| | | | | |
| +---------+ | +-------------+
| |
+-----------------+
Figure 4: COPS DS and RSVP Clients in Same Edge Device
Allowing multiple COPS client types to co-exist in a single PEP means
that the same PDP can coordinate policy decisions in an environment
where, say, both RSVP/IntServ and DiffServ QoS mechanisms need to be
managed. For example, in a stub network that uses IntServ with RSVP
signaling internally and is connected to a DiffServ transit network
externally. In this case, the edge device that connects the stub
network to the transit network may require policy decisions from the
same PDP for both RSVP requests as well as for policy rules to
enforce on the egress (DiffServ is with respect to the ingress)
interface.
The two decisions may very well need to be coordinated to ensure
proper provisioning and allocation of network resources. For example,
the decision of whether to admit an RSVP flow, or not, would depend
on the provisioning policy in place at the egress interface where the
COPS Usage for Differentiated Services December 1998
flow is leaving the stub network, and vice versa. The issue of
combining IntServ and DiffServ to provide an end-to-end QoS solution
is discussed in the draft [E2E]. Also, the RSVP WG is currently
planning on addressing the use of RSVP within the differentiated
services QoS model.
2.2 Interaction between the PDP and the PEP
When a device boots, it opens a COPS connection to its Primary PDP.
When the connection is established, the PEP sends information about
itself to the PDP in the form of a configuration request. This
information includes client specific information (hardware type,
software release, configuration information). During this phase the
client also specifies the maximum COPS-DS message size supported (see
Section 3.3).
In response, the PDP downloads all provisioned policies which are
currently relevant to that device. On receiving the provisioned
policies, the device maps them into its local QoS mechanisms, and
installs them. If conditions change at the PDP such that the PDP
detects that changes are required in the provisioned policies
currently in effect at the PEP, then the PDP sends the changes
(installs/deletes) in policy to the PEP, and the PEP updates its
local QoS mechanisms appropriately.
If, subsequently, the configuration of the device changes (board
removed, board added, new software installed, etc.) in ways not
covered by policies already known to the PEP, then the PEP sends this
new information to the PDP. On receiving this new information, the
PDP sends to the PEP any additional provisioned policies now needed
by the PEP.
3. The definition of the Policy Tree 3. The definition of the Policy Tree
This section defines data format for the diff serv client specific This section defines data format for the DiffServ client specific
information carried in the Decision, Request ClientSI, and Report information carried in the Decision, Request ClientSI, and Report
ClientSI objects. Diff serv client specific data may be defined for ClientSI objects. DiffServ client specific data may be defined for
the other objects in the future. the other objects in the future. COPS-DS data is represented by a
policy tree containing Policy Rule Classes (PRCs) and Instances of
those classes (PRIs), as shown in Figure 5.
The policy tree is based on SMI and MIBs. COPS for RSVP does not need COPS Usage for Differentiated Services December 1998
a policy tree, since the information exchanged has a simple format.
However, the COPS protocol does not preclude the use of data,
represented in such a way, with RSVP. COPS for DiffServ needs much
more structure, since it needs to represent policies, mappings, ACLs,
interfaces etc.
The policy tree is structured in the following way: -------+-------+----------+---PRC--+--PRI
| | | +--PRI
| | +---PRC-----PRI
| +---PRC--+--PRI
| | +--PRI
| | +--PRI
| | +--PRI
| | +--PRI
| +---PRC-----PRI
+---PRC---PRI
-------+-------+----------+---PC--+--PI Figure 5: Example of a Policy Tree
| | | +--PI
| | +---PC-----PI
| +---PC--+--PI
| | +--PI
| | +--PI
| | +--PI
| | +--PI
| +---PC-----PI
+---PC---PI
Figure 1: Example of a Policy Tree The policy tree is based on SMI and MIBs. COPS for RSVP does not need
a policy tree, since the information exchanged has a simple format
and is defined by existing RSVP objects. COPS for DiffServ needs much
more structure, since it needs to represent policies, mappings, ACLs,
interfaces etc.
PIs (Policy Instances) and s PRIs (Policy Rule Instances) and PRCs (Policy Rule Classes) have
PC (Policy Classes) have names (PIDs: names called PRIDs (Policy Rule IDentifiers). PRIDs have a
Policy Identifiers). Names have a hierarchical structure of the form hierarchical structure of the form 1.3.4.2.7, where the first part
1.3.4.2.7, where the first part identifies the PC (e.g., 1.3.4) and identifies the PRC (e.g., 1.3.4) and the last part identifies the
the last part identifies the instance (e.g. 2.7). instance (e.g. 2.7).
The policy tree names all the policy data classes and instances and The policy tree names all the policy rule classes and instances and
this creates a common view of the policy organization between the this creates a common view of the policy organization between the
Reichmeyer, Ho Chan, Durham, Gai, McCloghrie [Page
7]
COPS Usage for Differentiated Services August 1998
client (PEP) and the server (PDP). Therefore, when the PEP receives client (PEP) and the server (PDP). Therefore, when the PEP receives
data from the PDP, the data itself specifies what a PEP is supposed data from the PDP, the data itself specifies what a PEP is supposed
to do with the data. The current granularity of access, i.e., the to do with the data. The current granularity of access, i.e., the
atomicity of replacement, is proposed as a vector of values. atomicity of replacement, is proposed as a vector of values.
Note that the PCs/PIs in the above diagram are each a vector of Note that the PRCs/PRIs in the above diagram are each a vector of
values. This proposal is that the hierarchy of PCs/PIs is for benefit values. This proposal is that the hierarchy of PRCs/PRIs is for
of human understanding, not for programmatic understanding, or benefit of human understanding, not for programmatic understanding,
inheritance. or inheritance.
3.1 Description of the Policy Tree 3.1 Description of the Policy Tree
The Policy Tree is described using SMI and PIBs. SMI and PIBs are The Policy Tree is described using SMI and PIBs. SMI and PIBs are
defined based on the ASN.1 data definition language [ASN1]. This does defined based on the ASN.1 data definition language [ASN1]. To
not imply that the representation of the policy information on the simplify the implementation and re-use the SNMP encoding/decoding
wire must follow ASN.1: on the contrary, the proposal it to follow
COPS conventions and to define a new objects (XDR Encoded Policy
Instance Data, see Section 4.2) which contains an XDR encoding. XDR
is a standard [RFC1832] for the description and encoding of data.
3.2 Operations Supported On a PI COPS Usage for Differentiated Services December 1998
The following operations are supported on a PI: code, the representation of the policy information on the wire must
follow BER both for the PRID and for the BPD [BER].
o Install - creates a new instance of a PC, i.e. a new PI, or 3.2 Operations Supported On a PRI
The following operations are supported on a PRI:
o Install - creates a new instance of a PRC, i.e. a new PRI, or
modifies an existing instance. The instance is automatically modifies an existing instance. The instance is automatically
enabled. Parameters to this operation are a PID (see Section 4.1) enabled. Parameters to this operation are a PRID (see Section 4.1)
and an "XPD (XDR encoded policy instance Data)" containing the and an "BPD (BER encoded Policy instance Data)" containing the
value to assign to the new PI see (Section 4.2). The XPD specifies value to assign to the new PRI see (Section 4.2). The BPD specifies
all the attributes of the new PI. all the attributes of the new PRI.
o Delete - This operation is used to delete an instance of a PC. The o Delete - This operation is used to delete an instance of a PRC. The
parameter is a PID (see Section 4.1). parameter is a PRID (see Section 4.1).
o Enable. This operation is used to enable a PI. 3.3 PIB general information
o Disable. This operation is used to disable a PI. The PIB has a branch that contains general information. Examples of
information stored in this branch are:
3.3 An example of a PIB o TTL (Time To Live): a period of time in seconds. In the event the
PEP looses the COPS-DS connection with the PDP, it tries to re-
establish the connection with the primary and secondary PDPs. If
this fails for a period of time greater than the TTL, the DS
policies are discarded. The TTL specified in this branch is the
default TTL and may be overridden by TTLs present in specific
branches. A TTL = 0 means infinite.
o MCMS (Maximum COPS-DS Message Size): a message size in bytes. The
COPS-DS Client-Open ClientSI MUST specify the MCMS supported by the
client. This value must be in the range 4KB - 64KB.
o Interface to be provisioned.
o Capability information: This may include what filters the PEP
supports, what kind of profiles or dispositions it can perform.
3.4 An example of a PIB
This section contains a simple example of a PIB describing a simple This section contains a simple example of a PIB describing a simple
set of filters for IP packets. Each filter is able to match either set of filters for IP packets. Each filter is able to match either
the source IP address, the destination IP address or both. This the source IP address, the destination IP address or both. This
Reichmeyer, Ho Chan, Durham, Gai, McCloghrie [Page COPS Usage for Differentiated Services December 1998
8]
COPS Usage for Differentiated Services August 1998
example is provided only for the benefit of understanding how a PIB example is provided only for the benefit of understanding how a PIB
is structured. It is not supposed to describe any actual policy data. is structured. It is not necessarily supposed to describe any actual
policy data.
policyFilterPIB OBJECT IDENTIFIER ::= { policyPIB 1 } policyFilterPIB OBJECT IDENTIFIER ::= { policyPIB 1 }
ipHeaderFilterTable OBJECT-TYPE ipHeaderFilterTable OBJECT-TYPE
SYNTAX SEQUENCE OF IpHeaderFilterEntry SYNTAX SEQUENCE OF IpHeaderFilterEntry
MAX-ACCESS not-accessible MAX-ACCESS not-accessible
STATUS current STATUS current
DESCRIPTION "This table contains a simple ACL, i.e. one or DESCRIPTION "This table contains a simple ACL, i.e. one or
more IP filters." more IP filters."
skipping to change at line 420 skipping to change at page 12, line 4
ipHeaderFilterMatchType BITS, ipHeaderFilterMatchType BITS,
ipHeaderFilterSourceAddress IpAddress, ipHeaderFilterSourceAddress IpAddress,
ipHeaderFilterDestinationAddress IpAddress ipHeaderFilterDestinationAddress IpAddress
} }
ipHeaderFilterIndex OBJECT-TYPE ipHeaderFilterIndex OBJECT-TYPE
SYNTAX INTEGER SYNTAX INTEGER
MAX-ACCESS not-accessible MAX-ACCESS not-accessible
STATUS current STATUS current
DESCRIPTION "The index of the table, used to identify each DESCRIPTION "The index of the table, used to identify each
individual IP filter"
Reichmeyer, Ho Chan, Durham, Gai, McCloghrie [Page COPS Usage for Differentiated Services December 1998
9]
COPS Usage for Differentiated Services August 1998 individual IP filter"
::= {ipHeaderFilterEntry 1} ::= {ipHeaderFilterEntry 1}
ipHeaderFilterMatchType OBJECT-TYPE ipHeaderFilterMatchType OBJECT-TYPE
SYNTAX BITS { SYNTAX BITS {
matchSource (0), matchSource (0),
matchDestination (1) matchDestination (1)
} }
MAX-ACCESS not-accessible MAX-ACCESS not-accessible
STATUS current STATUS current
skipping to change at line 461 skipping to change at page 13, line 5
ipHeaderFilterDestinationAddress OBJECT-TYPE ipHeaderFilterDestinationAddress OBJECT-TYPE
SYNTAX IpAddress SYNTAX IpAddress
MAX-ACCESS not-accessible MAX-ACCESS not-accessible
STATUS current STATUS current
DESCRIPTION "IP destination address to be matched against the DESCRIPTION "IP destination address to be matched against the
packet in the event the ipHeaderFilterMatchType has the packet in the event the ipHeaderFilterMatchType has the
corresponding bit set. corresponding bit set.
::= {ipHeaderFilterEntry 4} ::= {ipHeaderFilterEntry 4}
COPS Usage for Differentiated Services December 1998
4. COPS Diff Serv Client Data 4. COPS Diff Serv Client Data
The COPS-DS extensions define a new client type: The COPS-DS extensions define a new client type:
Client Type = 2; Diff Serv Client Client Type = 2; Diff Serv Client
Diff serv specific information is sent in a COPS message containing a DiffServ specific information is sent in a COPS message containing a
Common Header with the Diff Serv Client type specified: Common Header with the Diff Serv Client type specified:
Reichmeyer, Ho Chan, Durham, Gai, McCloghrie [Page
10]
COPS Usage for Differentiated Services August 1998
0 1 2 0 1 2
3 3
+----------------+----------------+----------------+----------------+ +----------------+----------------+----------------+----------------+
| Version| //// | Op Code | Client Type = 0x02 | | Version| //// | Op Code | Client Type = 0x02 |
+----------------+----------------+----------------+----------------+ +----------------+----------------+----------------+----------------+
| Message Length | | Message Length |
+----------------+----------------+----------------+----------------+ +----------------+----------------+----------------+----------------+
The COPS protocol specification defines several objects which may The COPS protocol specification defines several objects which may
carry client specific information between PDP and PEP: carry client specific information between PDP and PEP:
Context Object (Context)
Reason Object (Reason)
Decision Object (Decision)
Error Object (Error)
Client Specific Information Object (ClientSI) which includes:
Request ClientSI
Report ClientSI
Client-Open ClientSI
4.1 Policy Identifier (PID) o Context Object (Context)
o Reason code Object (Reason code)
o Decision Object (Decision)
o Error Object (Error)
o Client Specific Info Object (ClientSI) which includes:
o Request ClientSI
o Report ClientSI
o Client-Open ClientSI
This object is used to carry the PID of the Policy Data Instance to 4.1 Policy Identifier (PRID)
This object is used to carry the PRID of the Policy Rule Instance to
be installed or deleted. be installed or deleted.
0 1 2 3 0 1 2 3
+----------------+----------------+----------------+----------------+ +----------------+----------------+----------------+----------------+
| Length | Type = PID | | Length | Type = PRID |
+----------------+----------------+----------------+----------------+ +----------------+----------------+----------------+----------------+
| Policy Identifier | | Policy Rule Identifier |
+----------------+----------------+----------------+----------------+ +----------------+----------------+----------------+----------------+
4.2 XDR Encoded Policy Instance Data (XPD) COPS Usage for Differentiated Services December 1998
4.2 BER encoded Policy instance Data (BPD)
This object is used to carry the value of a Policy Data Instance to This object is used to carry the value of a Policy Data Instance to
be installed, It contains an XDR coding of the Policy Data Instance be installed, It contains an BER coding of the Policy Data Instance
[RFC1832]. [BER].
0 1 2 3 0 1 2 3
+----------------+----------------+----------------+----------------+ +----------------+----------------+----------------+----------------+
| Length | Type = "XDR type" | | Length | Type = "BER type" |
+----------------+----------------+----------------+----------------+ +----------------+----------------+----------------+----------------+
| XDR Encoded PI Value | | BER Encoded PRI Value |
+----------------+----------------+----------------+----------------+ +----------------+----------------+----------------+----------------+
Reichmeyer, Ho Chan, Durham, Gai, McCloghrie [Page
11]
COPS Usage for Differentiated Services August 1998
4.3 Diff Serv Decision Data 4.3 Diff Serv Decision Data
The diff serv Client Specific Decision Data is composed of one or The DiffServ Named Decision Data (<Decision: Named Data>, see Section
more bindings. Each binding associates a PID object and an XPD 5.2) is composed of one or more bindings. Each binding associates a
object. The XPD object contains the value to be assigned to the PI PRID object and an BPD object. The PRID object is always present, the
that is created or updated. BPD object MUST be present in the case of an install decision and
MUST NOT be present in the case of a delete decision.
The diff serv specific decision data has the following format: The BPD object contains the value to be assigned to the PRI that is
created or updated.
The DiffServ specific decision data uses the following format:
C-Num = 7 C-Num = 7
C-Type = 4 C-Type = 5
<Client Specific Decision Data> ::= <Install> | <Decision: Named Data> ::= <Install Decision> |
<Delete> | <Remove Decision>
<Enable> |
<Disable>
<Install> :: = <Binding(s)> This depends from the <Decision: Flag>, see Section 5.2.
<Install Decision> :: = <Binding(s)>
<Binding(s)> ::= <Binding> <Binding(s)> | <Binding(s)> ::= <Binding> <Binding(s)> |
<Binding> <Binding>
<Binding> ::= <PID> <XPD> <Binding> ::= <PRID> <BPD>
<Delete> ::= <PI(s)> <Remove Decision> ::= <PRID(s)>
<Enable> ::= <PI(s)>
<Disable> ::= <PI(s)>
<PI(s)> ::= <PI> <PI(s)> | <PRID(s)> ::= <PRID> <PRID(s)> |
<PI> <PRID>
COPS Usage for Differentiated Services December 1998
Please note that the delete has the capability of deleting an entire
table with a single operation.
4.4 Diff Serv Request Data 4.4 Diff Serv Request Data
The diff serv request ClientSI data has the following format: The diffServ Configuration request will utilize the COPS Named
ClientSI (C-Num=10 C-Type=2) object to carry the same bindings as
described above. The DiffServ request Named ClientSI data has the
following format:
<diff serv request datat> ::= <Binding(s)> <ClientSI: Named> ::= <DiffServ Request Data>
<DiffServ Request Data (Named ClientSI)> ::= <Binding(s)>
4.5 Diff Serv Report Data 4.5 Diff Serv Report Data
Diff serv specific report data is used in the RPT message. The format DiffServ specific report data is used in the RPT message. The format
of the report data is dependant on the value of the accompanying COPS of the report data is dependant on the value of the accompanying COPS
Report Type object. Report Type object. Report types can be Installed/Removed or
NotInstalled/NotRemoved indicating to the PDP that a particular set
of policies has been either successfully or unsuccessfully
installed/deleted on the PEP.
Reichmeyer, Ho Chan, Durham, Gai, McCloghrie [Page 4.5.1 Successfully Installed/Removed Data
12]
COPS Usage for Differentiated Services August 1998
4.5.1 Commit Data When used with the "Installed" or "Removed" report type, the DiffServ
When used with the "commit" report type, the diff serv specific Named ClientSI object in the Report Message has the following
report data has the following format: format:
<diff serv report data> ::= [<PID(s)>] <ClientSI: Named> ::= <DiffServ Report Data>
4.5.2 No Commit Data <DiffServ report data> ::= [<PRID(s)>]
When used with the "no commit" report type, the diff serv specific
report data has the following format:
<diff serv report data> ::= <Binding(s)> where <PRID(s)> is the set of PRID successfully installed/deleted.
4.5.2 Unsuccessfully Installed/Removed Data
When used with the "Not Installed" or "Not Removed" report type, the
DiffServ specific report data has the following format:
<ClientSI: Named> ::= <DiffServ Report Data>
COPS Usage for Differentiated Services December 1998
<DiffServ report data> ::= <no-comit(s)>
<no-commit(s)> ::= <no-commit> | <no-commit(s)> <no-commit>
<no-commit> ::= <PRID> <Error> [<Binding(s)>]
where:
<PRID> is the PRID of the unsuccessful install/delete, <Error> is the
error code and <Binding(s)> are conflicting bindings that caused the
error.
The COPS-DS adds also the following two error codes:
- 12 COPS Client Specific Error Code;
- 13 Vendor Specific Error Code.
In the case of "no commit" the PEP MUST report at least the first
error and should report as many errors as possible.
4.5.3 Accounting Data 4.5.3 Accounting Data
TBD TBD
5. Message Content 5. Message Content
This section describes the COPS messages exchanged between a PEP and This section describes the COPS messages exchanged between a PEP and
PDP for use with diff serv policy services. PDP for use with DiffServ policy services.
5.1 Request (REQ) PEP -> PDP 5.1 Request (REQ) PEP -> PDP
The REQ message is used by COPS diff serv clients for issuing a The REQ message is used by COPS DiffServ clients for issuing a config
config request from the to the PDP, as described in the COPS request to the PDP, as described in the COPS protocol. The Client
protocol. The Client Handle is associated with request state Handle is associated with request state originated by the PEP and the
originated by the PEP and the PEP is responsible for notifying the PEP is responsible for notifying the PDP when the Handle is no longer
PDP when the Handle is no longer in use and can be deleted. in use and can be deleted.
The diff serv request data, defined above, may be included in the The DiffServ request data, defined above, may be included in the
config request form PEP to PDP. Currently, the request data is config request form PEP to PDP. Currently, the request data is
defined for carrying configuration/feature negotiation information defined for carrying configuration/feature negotiation information
from the PEP. This provides the server with information on the types from the PEP. This provides the server with information on the types
of policy that the interface can enforce and the types of policy data of policy that the interface can enforce and the types of policy data
the PEP can install. the PEP can install.
COPS Usage for Differentiated Services December 1998
The config request message serves as a request from the PEP to the The config request message serves as a request from the PEP to the
PDP for any diff serv configuration data which the PDP may have pre- PDP for any DiffServ configuration data which the PDP may have pre-
defined for the PEP device, such as access control lists, etc., and defined for the PEP device, such as access control lists, etc., and
any future access data or updates. The pre-configured and any any future access data or updates. The pre-configured and any
asynchronous diff serv configuration data can then be sent to the PEP asynchronous DiffServ configuration data can then be sent to the PEP
over time via responses, as decided by the PDP. The configuration over time via decisions, as decided by the PDP. The configuration
Reichmeyer, Ho Chan, Durham, Gai, McCloghrie [Page
13]
COPS Usage for Differentiated Services August 1998
information supplied by the PDP is of the consistent client specific information supplied by the PDP is of the consistent client specific
format defined above. The PDP responds to the config request with a format defined above. The PDP responds to the config request with a
DEC message containing any available configuration information. DEC message containing any available configuration information.
<Request> ::= <Common Header> <Request> ::= <Common Header>
<Client Handle> <Client Handle>
<Context = config request> <Context = config request>
<interface> [ <interface> ]
<diff serv request data> <DiffServ request data>
5.2 Decision (DEC) PDP -> PEP 5.2 Decision (DEC) PDP -> PEP
The DEC message is sent from the PDP to a diff serv client in The DEC message (<Decision Message>) is sent from the PDP to a
response to a config REQ received from the PEP. The Client Handle DiffServ client in response to a config REQ received from the PEP.
must be the same Handle that was received in the REQ message. The The Client Handle must be the same Handle that was received in the
Client Specific Decision Data for diff serv clients, to be used in REQ message. The Client Specific Decision Data for DiffServ clients
the DEC message, is defined above. (<Decision: ClientSI Data>), to be used in the DEC message, is
defined in Section 4.3.
The DEC message is sent as an immediate response to a config request, The DEC message is sent as an immediate response to a config request
used to carry pre-defined configuration information set in the PDP, with the solicited decision flag set, used to carry pre-defined
to the PEP. Subsequent DECs may also be sent at any time after the configuration information set in the PDP, to the PEP. Subsequent DEC
original DEC message to continue supplying the PEP with messages may also be sent at any time after the original DEC message
additional/updated policy information. The state carried in the DEC to continue supplying the PEP with additional/updated policy
message is referred to in the PDP and PEP by the Client Handle and information. The state carried in the DEC message is correlated with
the PID information. an initial request state by the Client Handle and provides the
The PEP performs the operation specified in the Decision Flags object appropriate PRID information.
on the decision data. If no configuration state is available when the
config REQ is processed by the PDP, a DEC is sent with the "No
Configuration Data" decision flag set.
The "Install", "Delete", "Enable", and "Disable" decision flags are Each DEC message may contain multiple decisions. This allows with a
used by the PEP and PDP to manage the policy data transactions. In single message to install some policies and delete some others. In
response to a DEC message, the diff serv client sends a RPT back to general a COPS-DS decision message should contain at most one delete
the PDP to inform the PDP of the actual action taken. For example, in decision followed by at most one install decision. This is used to
response to a DEC with the "Install" flag (only) set, the PEP informs solve a precedence issue, not a timing issue: the delete decision
the PDP if the decision data can be installed, based on the other deletes what it specifies, except those items that are installed in
policy data on the device (are there conflicts, etc.). Then when the the same message.
PDP determines the policy should be enabled, based on the transaction
associated with the policy data, a subsequent DEC message may be sent
with the "Enable" flag set.
<Decision> ::= <Common Header> A COPS-DS decision message is also a "transaction", i.e. all the
bindings in a message either succeed or fail. This allow to delete
some policies only if other policies can be installed in their place.
COPS Usage for Differentiated Services December 1998
For each decision (<Decision>), the PEP performs the operation
specified in the Decision Flags object (<Decision: Flags>) on the
decision data (<Decision: ClientSI Data>]).
<Decision Message> ::= <Common Header>
<Client Handle> <Client Handle>
<Decision Flags> <Decision(s)> | <Error>
[< diff serv Specific Decision Data>]
Reichmeyer, Ho Chan, Durham, Gai, McCloghrie [Page <Decision(s)> ::= <Decision> | <Decision(s)> <Decision>
14]
COPS Usage for Differentiated Services August 1998 <Decision> ::= <Context>
<Decision: Flags>
[<Decision: Named Data>]
If no configuration state is available when the config REQ is
processed by the PDP, a DEC is sent with the "No Configuration Data"
decision flag set.
In response to a DEC message, the DiffServ client sends a RPT back to
the PDP to inform the PDP of the actual action taken. For example, in
response to a DEC with the "Install" flag (only) set, the PEP informs
the PDP if the decision data can be installed, based on the other
policy data on the device (are there conflicts, etc.).
5.3 Report State (RPT) PEP -> PDP 5.3 Report State (RPT) PEP -> PDP
The RPT message is sent from the diff serv client to the PDP to The RPT message is sent from the DiffServ client to the PDP to report
report accounting information from PEP to PDP on request state accounting information from PEP to PDP on request state installed at
installed at the PEP. It is also used as a mechanism to inform the the PEP. It is also used as a mechanism to inform the PDP about the
PDP about the action taken at the PEP, in response to a DEC message. action taken at the PEP, in response to a DEC message. The DiffServ
The diff serv report data format, as defined above, depends on the report data format, as defined above, depends on the Report Type
Report Type included in the RPT message. included in the RPT message.
<Report State> ::= <Common Header> <Report State> ::= <Common Header>
<Client Handle> <Client Handle>
<Report Type> <Report Type>
[<diff serv report data>] [<DiffServ report data>]
6. Common Operation 6. Common Operation
This section describes, in general, typical exchanges between a PDP This section describes, in general, typical exchanges between a PDP
and diff serv COPS client. and DiffServ COPS client.
First, a connection is established between the PEP and PDP and the First, a connection is established between the PEP and PDP and the
PEP sends a Client-Open message with the Client-Type = 2, Diff Serv PEP sends a Client-Open message with the Client-Type = 2, Diff Serv
COPS Usage for Differentiated Services December 1998
client. If the PDP supports the Diff Serv client, the PDP responds client. If the PDP supports the Diff Serv client, the PDP responds
with a Client-Accept (CAT) message. If the client type is not with a Client-Accept (CAT) message. If the client type is not
supported, a Client-Close (CC) message is returned by the PDP to the supported, a Client-Close (CC) message is returned by the PDP to the
PEP, possibly identifying an alternate server that is known PEP, possibly identifying an alternate server that is known
(believed?) to support the policy for the diff serv client. (believed?) to support the policy for the DiffServ client.
Once the CAT message is accepted, the client can send requests to the Once the CAT message is received, the client can send requests to the
server. The first request a COPS Diff Serv client sends to the server server. The request a COPS DiffServ client sends to the server is for
is for configuration information, that is a REQ with "Configuration configuration information, that is a REQ with "Configuration Request"
Request" set in the context object that identifies a specific set in the context object that identifies a specific interface/module
interface/module and any relevant client specific information. The and any relevant client specific information (see also Section 3.3).
config request message serves two purposes in COPS-DS. First, it is a The config request message serves two purposes in COPS-DS. First, it
request from the PEP to the PDP for any diff serv configuration data is a request from the PEP to the PDP for any DiffServ configuration
which the PDP may have pre-defined for the PEP device, such as acces data which the PDP may have pre-defined for the PEP device, such as
control lists, etc. Also, the config request is a request to the PDP acces control lists, etc. Also, the config request is a request to
to send asynchronous diff serv configuration data to the PEP, as it the PDP to send asynchronous DiffServ configuration data to the PEP,
is received by the PDP. This asynchronous data may be new policy data as it is received by the PDP. This asynchronous data may be new
or an update to policy data sent previously. policy data or an update to policy data sent previously.
If the PDP has diff serv QoS policy configuration information for the If the PDP has DiffServ QoS policy configuration information for the
client, that information is returned to the client in a DEC message client, that information is returned to the client in a DEC message
containing the Diff Serv client policy data within the COPS Decision containing the Diff Serv client policy data within the COPS Decision
object. If no filters are defined, the DEC message will simply object. If no filters are defined, the DEC message will simply
specify that there are no filters using the "No Configuration" specify that there are no filters using the "No Configuration"
Decision Flags object. The PEP MUST specify a client handle (which
Reichmeyer, Ho Chan, Durham, Gai, McCloghrie [Page can be zero) in the request message. The PDP MUST process the client
15] handle and copy it in the decision message. This is to prevent the
COPS Usage for Differentiated Services August 1998 PEP from timing out the REQ and deleting the Client Handle.
Decision Flags object. The handle associated with the request state
is the Client Handle sent in the original configuration REQ from the
PEP. This is to prevent the PEP from timing out the REQ and deleting
the Client Handle.
The PDP can then add new policy data or update existing state by The PDP can then add new policy data or update existing state by
sending subsequent DEC message(s) to the PEP, with the same Client sending subsequent DEC message(s) to the PEP, with the same Client
Handle. The PEP is responsible for removing the Client handle when it Handle. The PEP is responsible for removing the Client handle when it
is no longer needed, for example when the interface goes down, and is no longer needed, for example when the interface goes down, and
informing the PDP that the handle is to be deleted. informing the PDP that the handle is to be deleted.
For diff serv purposes, access state, and access requests to the For DiffServ purposes, access state, and access requests to the
policy server can be initiated by other sources besides the PEP. policy server can be initiated by other sources besides the PEP.
Examples of other sources include attached users requesting network Examples of other sources include attached users requesting network
services via a web interface into a central management application, services via a web interface into a central management application,
or H.323 servers requesting resources on behalf of a user for a video or H.323 servers requesting resources on behalf of a user for a video
conferencing application. When such a request is accepted, the edge conferencing application. When such a request is accepted, the edge
device affected by the decision (the point where the flow is to enter device affected by the decision (the point where the flow is to enter
the network) must be informed of the decision. Since the PEP in the the network) must be informed of the decision. Since the PEP in the
edge device did not initiate the request, the specifics of the edge device did not initiate the request, the specifics of the
request, e.g. flowspec, packet filter, and PHB to apply, must be request, e.g. flowspec, packet filter, and PHB to apply, must be
communicated to the PEP by the PDP. This information is sent to the communicated to the PEP by the PDP. This information is sent to the
COPS Usage for Differentiated Services December 1998
PEP using the Decision message containing Diff Serv client specific PEP using the Decision message containing Diff Serv client specific
data objects in the COPS Decision object as specified. Any updates to data objects in the COPS Decision object as specified. Any updates to
the state information, for example in the case of a policy change or the state information, for example in the case of a policy change or
call tear down, is communicated to the PEP by subsequent DEC messages call tear down, is communicated to the PEP by subsequent DEC messages
containing the same Client Handle and the updated diff serv request containing the same Client Handle and the updated DiffServ request
state. Updates can be specify to delete, install, enable or disable state. Updates can specify that policy data is to be deleted or
existing policy data. installed.
The PEP acknowledges the DEC message and action taken by sending a The PEP acknowledges the DEC message and action taken by sending a
RPT message with a "Commit" Report-Type object. This serves as an RPT message with a "Installed" or "Removed" Report-Type object. This
indication to the PDP that the requestor (e.g. H.323 server) can be serves as an indication to the PDP that the requestor (e.g. H.323
notified that the request has been accepted by the network. If the server) can be notified that the request has been accepted by the
PEP needs to reject the DEC operation for any reason, a RPT message network. If the PEP needs to reject the DEC operation for any reason,
is sent with a Report-Type of value "No Commit" and optionally a a RPT message is sent with a Report-Type of value "Not Installed" or
Client Specific Information object specifying the policy data that "Not Removed" and optionally a Client Specific Information object
was rejected. The PDP can then respond to the requestor accordingly. specifying the policy data that was rejected. The PDP can then
respond to the requestor accordingly.
The PEP can report to the PDP the local status of any installed The PEP can report to the PDP the local status of any installed
request state when appropriate. This information is sent in a Report- request state when appropriate. This information is sent in a Report-
State (RPT) message with the "Accounting" flag set. The state being State (RPT) message with the "Accounting" flag set. The state being
reported on is referenced by the Client Handle associated with the reported on is referenced by the Client Handle associated with the
request state and the client specific data identifier. request state and the client specific data identifier.
Finally, Client-Close (CC) messages are used to cancel the Finally, Client-Close (CC) messages are used to cancel the
corresponding Client-Open message. The CC message informs the other corresponding Client-Open message. The CC message informs the other
side that the client type specified is no longer supported. side that the client type specified is no longer supported.
Reichmeyer, Ho Chan, Durham, Gai, McCloghrie [Page
16]
COPS Usage for Differentiated Services August 1998
7. Fault Tolerance 7. Fault Tolerance
When communication is lost between PEP and PDP, the PEP attempts to When communication is lost between PEP and PDP, the PEP attempts to
re-establish the TCP connection with the PDP it was last connected re-establish the TCP connection with the PDP it was last connected
to. If that server cannot be reached, then the PEP attempts to to. If that server cannot be reached, then the PEP attempts to
connect to a secondary PDP, assumed at this time to be manually connect to a secondary PDP, assumed at this time to be manually
configured at the PEP. configured at the PEP.
When a connection is finally re-established, either with the primary When a connection is finally re-established, either with the primary
PDP or a secondary PDP, the PDP may request the PEP to re-synch its PDP or a secondary PDP, the PEP should provide the last PDP address
current state information (SSQ message). If after re-connecting, the of the PDP for which it is still caching decisions. Based on this
PDP does not request the synchronization, the client can assume the information, the PDP may request the PEP to re-synch its current
server recognizes it and the current state at the PEP is correct. Any state information (SSQ message). If no decisions are being cached on
changes state changes which occurred at the PEP while connection was the PEP (due to reboot or TTL timeout of state) the PEP must not
lost must be reported to the PDP in a RPT message. included the last PDP address information. If after re-connecting,
the PDP does not request the synchronization, the client can assume
the server recognizes it and the current state at the PEP is correct.
Any changes state changes which occurred at the PEP while connection
was lost must be reported to the PDP in a RPT message. If re-
COPS Usage for Differentiated Services December 1998
synchronization is requested, the PEP should reissue its
configuration requests and the PDP should delete the appropriate PRCs
on the PEP (thus, removing all previous decisions below the PRC,
effectively resetting all state).
While the PEP is disconnected from the PDP, the request state at the While the PEP is disconnected from the PDP, the request state at the
PEP is to be used for policy decisions. If the PEP cannot re-connect PEP is to be used for policy decisions. If the PEP cannot re-connect
in some pre-specified period of time (some multiple of the keep-alive in some pre-specified period of time (some multiple of the keep-alive
time? - TBD), the request state is to be deleted and the associated time? - TBD), the request state is to be deleted and the associated
Handles removed. The same holds true for the PDP; upon detecting a Handles removed. The same holds true for the PDP; upon detecting a
failed TCP connection, the time-out timer is started for the request failed TCP connection, the time-out timer is started for the request
state associated with the PEP and the state is removed after the state associated with the PEP and the state is removed after the
specified period without a connection. specified period without a connection.
8. Security 8. Security
The use of COPS for diff serv introduce no new security issues over The use of COPS for DiffServ introduce no new security issues over
the base COPS protocol. The use of IPSEC between PDP and PEP, as the base COPS protocol. The use of IPSEC between PDP and PEP, as
described in [COPS] is sufficient. described in [COPS] is sufficient.
9. References 9. References
[COPS] Boyle, J., Cohen, R., Durham, D., Herzog, S., Raja,n R., [COPS] Boyle, J., Cohen, R., Durham, D., Herzog, S., Raja, R.,
Sastry, A., "The COPS (Common Open Policy Service) Sastry, A., "The COPS (Common Open Policy Service)
Protocol", IETF <draft-ietf-rap-cops-02.txt>, March 1998. Protocol", IETF <draft-ietf-rap-cops-03.txt>, December
1998.
[RAP] Yavatkar, R., et al., "A Framework for Policy Based [RAP] Yavatkar, R., et al., "A Framework for Policy Based
Admission Control",IETF <draft-ietf-rap-framework-00.txt>, Admission Control",IETF <draft-ietf-rap-framework-00.txt>,
November, 1997. November, 1997.
[E2E] Bernet, Y., Yavatka,r R., Ford, P., Bake,r F., Nichols, K., [E2E] Bernet, Y., Yavatka,r R., Ford, P., Baker, F., Nichols, K.,
Speer, M., "A Framework for End-to-End QoS Combining Speer, M., "A Framework for End-to-End QoS Combining
Reichmeyer, Ho Chan, Durham, Gai, McCloghrie [Page
17]
COPS Usage for Differentiated Services August 1998
RSVP/Intserv and Differentiated Services", IETF <draft- RSVP/Intserv and Differentiated Services", IETF <draft-
ietf-diffserv-rsvp-00.txt>, March 1998. ietf-DiffServ-rsvp-00.txt>, March 1998.
[RSVP] Braden, R., Zhang, L., Berson, S., Herzog, S., and Jamin, [RSVP] Braden, R., Zhang, L., Berson, S., Herzog, S., and Jamin,
S., "Resource Reservation Protocol (RSVP) Version 1 S., "Resource Reservation Protocol (RSVP) Version 1
Functional Specification", IETF RFC 2205, Proposed Functional Specification", IETF RFC 2205, Proposed
Standard, September 1997. Standard, September 1997.
[ASN1] Information processing systems - Open Systems [ASN1] Information processing systems - Open Systems
Interconnection, "Specification of Abstract Syntax Notation Interconnection, "Specification of Abstract Syntax Notation
One (ASN.1)", International Organization for One (ASN.1)", International Organization for
COPS Usage for Differentiated Services December 1998
Standardization, International Standard 8824, December Standardization, International Standard 8824, December
1987. 1987.
[RFC1832] R. Srinivasan, "XDR: External Data Representation [BER] Information processing systems - Open Systems
Standard.", RFC 1832, August 1995. Interconnection - Specification of Basic Encoding Rules for
Abstract Syntax Notation One (ASN.1), International
Organization for Standardization. International Standard
8825, (December, 1987).
[Nichols] K. Nichols, V. Jacobson, L. Zhang, " A Two-bit
Differentiated Services Architecture for the Internet,"
draft-nichols-diff-svc-arch-00.txt
10. Author Information 10. Author Information
Francis Reichmeyer Francis Reichmeyer
Bay Networks, Inc. Bay Networks, Inc.
3 Federal Street 3 Federal Street
Billerica, MA 01821 Billerica, MA 01821
Phone: (978) 916-3352 Phone: (978) 916-3352
Email: freichmeyer@BayNetworks.COM Email: freichmeyer@baynetworks.com
Kwok Ho Chan Kwok Ho Chan
Bay Networks, Inc. Bay Networks, Inc.
600 Technology Park 600 Technology Park
Billerica, MA 01821 Billerica, MA 01821
Phone: (978) 916-8175 Phone: (978) 916-8175
Email: khchan@BayNetworks.COM Email: khchan@baynetworks.com
David Durham David Durham
Intel Intel
2111 NE 25th Avenue 2111 NE 25th Avenue
Hillsboro, OR 97124 Hillsboro, OR 97124
Phone: (503) 264-6232 Phone: (503) 264-6232
Email: david.durham@intel.com Email: david.durham@intel.com
Raj Yavatkar Raj Yavatkar
Intel Intel
2111 NE 25th Avenue 2111 NE 25th Avenue
Hillsboro OR 97124 Hillsboro OR 97124
Phone: (503) 264-9077 Phone: (503) 264-9077
Email: yavatkar@ibeam.intel.com Email: yavatkar@ibeam.intel.com
Reichmeyer, Ho Chan, Durham, Gai, McCloghrie [Page
18]
COPS Usage for Differentiated Services August 1998
Silvano Gai Silvano Gai
Cisco Systems, Inc. Cisco Systems, Inc.
COPS Usage for Differentiated Services December 1998
170 Tasman Dr. 170 Tasman Dr.
San Jose, CA 95134-1706 San Jose, CA 95134-1706
Phone: (408) 527-2690 Phone: (408) 527-2690
email: sgai@cisco.com email: sgai@cisco.com
Keith McCloghrie Keith McCloghrie
Cisco Systems, Inc. Cisco Systems, Inc.
170 Tasman Dr. 170 Tasman Dr.
San Jose, CA 95134-1706 San Jose, CA 95134-1706
Phone: (408) 526-5260 Phone: (408) 526-5260
email: kzm@cisco.com email: kzm@cisco.com
Shai Herzog Shai Herzog
IPHighway IPHighway
2055 Gateway Place, Suite 400 400 Kelby St., Suite 1500
San Jose, CA 95110 Parker Plaza
Phone: (408) 451-3923 Fort Lee, NJ 07024
Phone: (201) 585-0800
Email: herzog@iphighway.com Email: herzog@iphighway.com
...........
Reichmeyer, Ho Chan, Durham, Gai, McCloghrie [Page
19]
 End of changes. 

This html diff was produced by rfcdiff 1.23, available from http://www.levkowetz.com/ietf/tools/rfcdiff/