Table of Contents
Managing PDPs
The Policy Decision Point (PDP), also called a policy server, is the interface between the QPM server and the network devices. It obtains the policy database from the QPM server and either populates devices with static QoS policy configuration or acts as policy decision maker for devices that outsource policy decision making.
Typical installation of QPM would include multiple PDPs spread over the network domain to scale with the number of network devices. PDPs use the COPS protocol to communicate with devices. PDPs also:
- Provide deployment and connectivity status to the QPM Server.
- Retrieve policies from the QPM Server upon deployment request.
- Maintain a log file listing the major events and decisions taken by the PDP.
This chapter presents the following topics related to PDPs:
PDPs are identified by their IP address or PDP host name. One PDP is installed during a Full Installation of QPM-COPS. The PDP service, Cisco Policy Server 1.0, can be stopped at any time.
Additional PDPs can be installed on other machines and refer to the machine where the Full Installation is located. Remote PDPs connect themselves to the QPM Server. Upon installation, the System Host entry in the QPM.ini file is updated to reflect the PDP-QPM Server connection.
PDPs improve network traffic flow by:
- Holding copies of the Policy database---This minimizes traffic by acting as a "middleman" between the devices and the QPM server.
- Filtering policies and roles---Policies and roles that are not appropriate for a particular device are filtered out; only the relevant policies and roles are forwarded to the device.
PDPs implement the following:
- Download Provisioning policy statements to the devices via COPS-PR.
- Respond to QoS reservation requests sent by the devices via COPS-RSVP.
- Implement the decision engines for both protocols.
Additionally, PDPs implement the following communication and control features:
- Maintain a TCP connection with each of its managed devices based on the COPS protocol.
- Maintain a connection with QPM Server.
- Serve as a backup PDP in case the primary PDP fails. In this case, the device connects with the backup PDP.
- Redirect a device to disconnect itself from the PDP and connect to an alternative PDP.
View PDP information in two ways:
- In the menu bar, choose Distribution Manager. From the Distribution Manager option bar, choose Manage PDPs.
- In the menu bar, choose Setup. From the Setup list or option bar, choose Manage PDPs.
The following page appears:
Figure 9-1: PDP Management Page
The fields in this page include:
- PDP---This field lists the system ID where the PDP is installed.
- IP---This field lists the IP address of the system where the PDP is installed.
- Version---This field lists two elements, separated by a comma. The first is the "product version number.minor version number.software build number." The second is the date that the software was built. In future product release notes, you may find a notice of an incompatibility between a particular software version and the software build number associated with the PDP. If you have a PDP with a build number that is no longer valid, you must delete and reinstall the PDP.
- Status---This field indicates whether the PDP is Connected to the QPM server or Unreachable. A PDP that was once known to the QPM server but is either no longer available or the PDP's host machine is down is considered Unreachable.
- Garbage Can---See Removing a PDP.
PDPs which are no longer used are marked as Unreachable. They are only removed by explicit user action.
Procedure
Step 1 In the menu bar, choose Setup. Choose Manage PDPs from the option bar. A page similar to that in Figure 9-1 appears. If a PDP is Unreachable, a Garbage Can icon appears next to the PDP in the last column of the table.
Step 2
Click the Garbage Can icon associated with the PDP that you want to remove.
Step 3 Stop the PDP service: In the Services dialog box (Figure 9-2), click the PDP service, Cisco Policy Server 1.0, and click Stop. By stopping this service, the PDP will no longer receive information from the QPM Server and will no longer send information to the devices to which it is connected.
Figure 9-2: Services Dialog Box
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Note Stopping the PDP service should be done on the machine where the PDP that you want to remove is running and NOT on the QPM Server host machine. |
Posted: Mon Jun 12 04:46:09 PDT 2000
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