Q: Why is the following message displayed on NetScaler SD-WAN appliance?
Average one-hour WAN Accelerated Traffic Send Rate exceeded the License Limit 

A: It means the accelerated traffic exceeded the license for a sustained period of time. A hardware upgrade of the NetScaler SD-WAN appliance should be considered.

Flow control does count against the license. As long as traffic is bypassed (not accelerated) it should not count against the license.

Q: Why are the FTW ports of a NetScaler SD-WAN appliance displayed on the GUI in bypass state? 

A: Rebooting the appliance will result in the relays going into bypass state. When that happens, traffic will flow unaccelerated. The data path ports will be displayed as DOWN in the GUI because the relays will connect the WAN and LAN ports directly. Once the unit completes reboot, the interfaces will be displayed as UP again in the GUI.

Q: When Transmission Mode is set to “Persistent Path”, which latency values would be used to decide whether to continue to use the path or use an alternate path? 

A: A lot of the path selection intelligence is coded into the system. There is no specific latency value that it is looking for. It is more of an comparison between all paths at any given time. When we set a persistent path, the system just adds additional latency penalty against the other paths (I could not track down the actual value, and it is not a value that is configurable), making your desired path the likely path during uncongested operation. The penalty is there just to keep the connection on a particular path until the congestion point on that path becomes worse enough where it is a less desired path versus the alternatives even with the added latency penalty. The system is desired to not kill any connections and to even out the traffic flow across all paths to avoid contention.

Q: Does NetScaler SD-WAN have specific protocol optimizations for SQL*Net? 

A: NetScaler SD-WAN does not have specific protocol optimizations for SQL*Net. SQL*Net chattiness is associated with the nature of SQL that returns data one record at a time to the user.  If the user sends a query with several database hits, each record will be sent individually, hence the chattiness. 

SQL*Net supports encryption, if encryption is enabled, there is no support for compression.  The NetScaler SD-WAN has to be placed as a man-in-the-middle to decrypt the SQL traffic in order to be able to compress the data.  If the data is not encrypted then normal compression and deduplication features should work just fine. Flow control and QoS will still help with the user experience.

Q: Why is the “CPU Graph” under Monitoring tab no longer available on version 7.3.x and later? 

A: On version 7.3.x and later the “CPU Graph” under Monitoring tab was removed as its values were getting misinterpreted. On Citrix documentation version 7.3 under Enhancements you can find the following snippet regarding Load Statistics: 
Load Statistics 
Citrix CloudBridge includes load statistics functionality that collates all parameters affecting the load on the appliance and displays the results in a graphical format. These graphs are available on the CloudBridge > Monitoring > Appliance Performance > Load Statistics page. To know more about load statistics, see Load Statistics. 

Then on the Section of Load Statistics you can find more information regarding Load Statistics Vs CPU: 
The load statistics are based on input queue latency rather than the CPU load, because a CloudBridge appliance makes use of all system resources, wherever possible. The input queue latency indicates the extent to which processing the queue has overloaded the appliance is to process the queue built up on the appliance. The queue latency measures the duration for which a packet waits before the appliance selects it for processing. The longer the wait time, the busier the appliance. If the value of the input queue latency rises and remains high for quite some time, the request queue builds up on the appliance and might result in connections with diminished acceleration.

This article lists the frequently asked questions about NetScaler SD-WAN performance.