Netscaler has the ability to use something called TCP profiles, which allows “non-TCP” experts to customize the Netscaler based upon what application is being used or what kind of network is be used or devices that are accessing the service.
Now this might be the easiest performance tuning feature on the Netscaler.
The different profiles can be viewed under System –> Profiles –> TCP Profiles
Now by default when you create a service or virtual server it will automatically bind itself to the nstcp_default_profile so let’s take a look at it.
If we for instance setup a Netscaler Gateway solution for ICA access, we should use the nstcp_default_XA_XD_profile. Why you say? let’s take a look at it and compare the difference.
Not so much differences here. except a couple of things.
* Window Scaling
* Nagle’s algorithm
* Selective Ack (SACK)
* Maximum Packets per MSS
* Maximum Packts per Retransmission
Now all the differences here are within a key area. ICA is a “chatty” procotol, which might send out a lot of small packets. nstcp_xa_xd profile allows the Netscaler to send more packets inside a TCP segment. Window scaling and Selective Acknowledgement are also enabled for this profile for better experience over long pipes. Nagle’s algorithm increases the efficiency of a network application system by decreasing the number of packets that must be sent.
By choosing this profile for a NS gateway you gain a lower ICA RTT and less latency since packets will flow faster. And note you can attach a profile to a vServer by going into Advanced –> Profiles –> TCP profiles