# SRC Client and COPS Terminology

Table 11 provides common terms used in the COPS environment.

Table 11: SRC Client and COPS Terminology

Term | Description
--- | ---
COPS | Common Open Policy Service; query-and-response protocol used to exchange policy information between a policy server and its clients.
COPS-PR | COPS usage for policy provisioning; the PEP requests policy provisioning when the operational state of interface and DHCP addresses changes.
PDP | Policy decision point; the COPS server. which makes policy decisions for itself and for clients that request decisions. The SRC software is the PDP.
PEP | Policy enforcement point; the COPS client, which enforces policy decisions. The JunosE COPS interface is a PEP.
PIB | Policy Information Base; a collection of sets of attributes that represent configuration information for a device.
SRC | Session and Resource Control (SRC) software, formerly the Service Deployment System (SDX) software; functions as a COPS PDP.

The JunosE Software COPS-PR implementation uses the outsourcing model that is described in RFC 3084. In this model, the PEP delegates responsibility to the PDP to make provisioning decisions on the PEP’s behalf.

| Note: When you upgrade from an earlier JunosE release, the software removes the instance of SSCC that was configured with XDR. If you are going to perform a unified ISSU from a JunosE release numbered lower than Release 10.0.0 and you have an XDR configuration, unified ISSU is not supported while an XDR configuration is presented.

The provisioning is event-driven and is based on policy requests rather than on an action taken by an administrator—the provisioning is initiated when the PDP receives external requests and PEP events. Provisioning can be performed in bulk (for example, an entire QoS configuration) or in smaller segments (for example, updating a marking filter). The following list shows the interaction between the PEP and the PDP during the COPS-PR operation.

1. Initial connection
   1. PEP starts the COPS-PR connection with the PDP.
   2. PDP requests synchronization.
   3. PEP sends all currently provisioned policies to PDP.
2. Change of interface state
   1. PEP requests provisioning of an interface from the PDP.
   2. PDP determines policies and sends provisioning data to the PEP.
   3. PEP provisions the policies.
3. PDP requests policy provisioning
   1. PDP determines new policies and sends provisioning data to the PEP.
   2. PEP provisions the policies.

The information exchange between the PDP and PEP consists of data that is modeled in Policy Information Bases (PIBs) and is encoded using the standard ASN.1 basic encoding rules (BERs).

JunosE Software uses the following PIBs:

Proprietary PIB

- JunosE-IP-PIB—This PIB defines the data model for manipulating IP service policies and addresses offered through DHCP in JunosE Software.

Non-proprietary PIBs

- COPS-PR-SPPI
- COPS-PR-SPPI-TC
- DIFFSERV-PIB
- FRAMEWORK-FEEDBACK-PIB
- FRAMEWORK-PIB
- FRAMEWORK-TC-PIB

The COPS-PR support in JunosE Software uses the proprietary PIB. This PIB consists of a series of tables that is supported in previous JunosE Software releases, including the proprietary accounting and address assignment mechanisms.

You can force the router to restart a COPS connection to, and resynchronize with, a PDP, without disabling the SRC client’s COPS support. The SRC software and the SRC client maintain common state information in PIBs that both the SRC software and the SRC client use. Previously, you disabled the SRC client and reenabled it to start synchronization. The disabling of the SRC client’s COPS support was undesirable for the applications that required resynchronization in addition to maintaining the COPS support. If the state of the SRC software is not synchronized with the router, the SRC software may be required to initiate resynchronization from the router.

The proprietary PIB provides the Policy Manager and QoS Manager functionality shown in the following lists.

- Policy Manager
  - Committed access rate
  - Packet filtering
  - Policy routing
  - QoS classification and marking
  - Rate limiting
  - Traffic class
- QoS Manager
  - Queues
  - Schedulers
  - Traffic classes

The JunosE-IP-PIB file is updated with each JunosE release. Since the PIB is implemented by both Juniper Networks SRC and JunosE devices, distribution of the PIB file to customers is not necessary. Customers can access the proprietary PIB file, on approval from Juniper Networks, through Juniper support.