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Some applications suffer when a Rate policy with 0M guaranteed is applied on a PacketShaper

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Article ID: 173921

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Updated On:

Products

PacketShaper S-Series

Issue/Introduction

Some applications experience slowness or suffer in performance when a Rate policy with 0M guaranteed is applied on a PacketShaper.

 

Cause

Rate policy is designed to manage or control traffic on per flow basis.

This policy is recommended if you know the bandwidth each flow requires so that you can guarantee that much band wise per flow.

Depending on application or environment, when you apply a Rate policy with 0M guaranteed with low burstable priority level, the flow will be allocated only minimal bandwidth in the beginning of the flow and will allocate more bandwidth based on the demand.

For a short bursty flows, the bandwidth allocation ramp up delay may be noticeable and the application may suffer.

 

Resolution

In order to have crisp performance without bandwidth allocation delay, you should avoid a Rate Policy using 0 guarantee.

Using a policy that allows immediate burst is needed when dealing with latency sensitive applications.

We suggest using Priority policy in such cases to make things simple. 

If you know exactly how much bandwidth each flow needs, you know the maximum number of flows at any given time and have adequate bandwidth then you can use Rate Policy with the required Guaranteed bandwidth and can make it burstable with a higher priority if needed. 

Note:  With a Rate Policy with guarantee, if there are more flows than it can guarantee bandwidth then the flows will be dropped. In order to avoid such situations, a Priority Policy with proper priority level is recommended.