Window-Scaling on ProxySG only using a scale-factor of 1

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Article ID: 167636

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Updated On:

Products

Advanced Secure Gateway Software - ASG ProxySG Software - SGOS

Issue/Introduction

The ProxySG has RFC-1323 enabled, but it's only requesting a scaling-factor of 1 when connecting to webservers, resulting in slow download speeds for large files on the network.

Resolution

Window-Scaling behaviour in SGOS with RFC-1323 enabled is currently as follows:


Inbound Connections
The ProxySG will accept whichever scaling-factor is requested by the client.

 

Outbound Connections:

With ADN enabled - the ProxySG will request a window scale of 6 by default.

With ADN disabled - the ProxySG will request a scaling-factor of 1 by default.

To allow for the use of larger scaling-factors, the TCP window-size should be increased. For example:
#(config)tcp-ip window-size 4194240

(TCP window-size is 65535 by default)