Nortel business policy switch 2000, Руководство пользователя

Страница: 307 / 412

Chapter 4 Policy-enabled networks 307
Using the Business Policy Switch 2000 Version 2.0
However, traffic destined for the switch and received through a port on the base
unit of a stack is not dropped even if filters targeting the traffic are installed and
drop has been specified. This behavior prevents you from completely isolating
yourself from the switch. Consider this behavior when you configure filters and
when you allocate ports for the purposes of configuring and or monitoring the
switch.
COPS overview
Common Open Policy Services (COPS) is important as a stateful protocol
between a policy server and a network device such as the BPS 2000. COPS is
implemented by using the Optivity Policy Services
* (OPS), Version 1.2 or later,
which is a comprehensive network management application. OPS provides a
centralized management point for DiffServ policies. The policy server distributes
policies to edge devices and border routers. These edge devices police traffic
flows by marking packets and applying forwarding behaviors to the packets at the
network node.
Information is transferred using the Common Open Policy Services (COPS)
protocol, a query and response protocol that exchanges policy information
messages using the Transmission Control Protocol (TCP). COPS ensures
redundancy for devices to contact an alternate policy server should the primary
server fail. Specifically, COPS for Provisioning (COPS-PR) is used to download
information.
COPS is used to communicate with edge devices on the network. Some of the
benefits of the COPS protocol are:
• It uses a client/server model for communication between the policy server and
the policy clients.
• It uses TCP for messaging, reducing the resources it requires.
• The policy server can send configuration information to the policy client, as
well as remove unneeded configuration information.
For information about OPS, and specific BPS 2000 implementation notes, go to
the
www.nortelnetworks.com/documentation URL. Then locate the specific
software product (in this case, Optivity Policy Services).