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.
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 nonessential
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 website 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.
See also:
Bandwidth Allocation
Policy/Partition
Guidelines
Protect
Critical Application Performance
Insulate
Users of the Same Application
Use Suggested Policies
Modify a Policy
Set an Policy or Partition with the Application Policy Manager
Delete a Policy
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