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Policy Overview

A policy determines how an application's individual flows are treated in the context of competing applications, and allows you to manage bandwidth management on a flow-by-flow basis. With policies, you can give each flow of mission-critical traffic the bandwidth it needs for optimum performance, as well as protect it from greedy, less important traffic. In addition, policies can keep non-urgent traffic flows (such as FTP) from consuming more than an appropriate share of bandwidth.

Note: An alternative way to assign policies is with the Easy Configure feature. This feature automatically assigns appropriate policies when you categorize a class as Mission Critical, Average, Low Priority, or Prohibited. For more information, see Assign Categories to Classes. This feature is not available on PacketShaper/ISP models.

Policy Types

PacketWise offers the following policy types:


Type	Description
Priority	Establishes a priority for traffic without specifying a particular rate. Use priority policies for non-IP traffic types, or traffic that does not burst (for example, Telnet). See Set a Priority Policy for details.
Rate	Smooths bursty traffic, such as HTTP, using Packeteer TCP rate-control technology. TCP rate control is an advanced congestion-avoidance mechanism whose goal is to prevent traffic from being sent at rates higher than the WAN connection, thereby greatly reducing queuing in router buffers and improving overall efficiency. See Set a Rate Policy for details.
Discard	Tosses all packets for a traffic class, thereby blocking the service. You might use this policy type for an application that is non-essential to your business and consumes too much of your network bandwidth. See Set a Discard Policy for details.
Ignore	Exempts a traffic class from bandwidth allocation and treats the traffic type as "pass-through" traffic. That is, the traffic won't be counted as part of the link traffic under management. Care should be taken when using this policy. If an ignore policy is placed on a class that is a major bandwidth consumer, other bandwidth allocation may be impacted. See Set an Ignore Policy for details.
Never-Admit	Restricts non-TCP traffic and intelligently rejects web and TCP traffic. Use this policy to redirect certain web users to alternate URLs. See Set a Never-Admit Policy for details.

Policies can be applied only to "leaf" classes — that is, classes that do not have children. For example, a parent class, /Inbound/HTTP, may have child classes that differentiate one web site from another: /Inbound/HTTP/ESPN and /Inbound/HTTP/MyCompany. In this example, policies can be placed on the ESPN and MyCompany classes (if they do not have children), but not on the parent class /Inbound/HTTP.

If a class has a policy and then you create a child class, a Default class is automatically created in this subtree and the parent class policy is transferred to this class. If all child classes are later deleted, the policy is transferred back to the parent class.