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Signiant's WAN Accelerator Aggressiveness rules Print


Question

What is WAN Accelerator Aggressiveness and how does it work?
 

Answer

Aggressiveness indicates how sensitive the WAN accelerator is to other network traffic when it is running. Signiant has three levels of aggressiveness:

High: The Agent always tries to send data at the bandwidth ceiling rate and only drops the transfer rate after detecting 3% of  packet loss. If so, then the transfer rate slows down to 94% of the current transfer rate.

Medium: The Agent always tries to send data at the bandwidth ceiling rate but lowers the transfer rate if 2% of packet loss is detected. At medium aggressiveness, the transfer rate slows down to 93% of the current transfer rate.

Low: The Agent always attempts to send data at the Bandwidth Ceiling rate, however, if as much as 1% of packet loss is detected, the Agent immediately drops the transfer rate. In this case, the transfer rate drops to 91% of the current transfer rate.  

Aggressiveness also specifies how aggressively the transfer attempts to reclaim bandwidth after packet loss. In the case of high aggressiveness, the transfer waits two intervals (interval = 10ms) before trying to increment the transfer rate by 5%. In medium, the transfer waits four intervals before trying to increase the transfer rate by 4% and in low aggressiveness, the transfer waits eight intervals before trying to increment the transfer rate by 3%.

(The following example and table provide more details.)
 
Example:

If only 98% of the packets of a transfer are getting through, this is the behavior with different aggressiveness levels:

Low: this causes the rate to slow down to 91% of its current speed. After 80 ms, the job tries to increase the transfer rate by 3% making a total of 94% of the initial transfer rate (assuming no packet loss is detected again).
Medium: the transfer rate slows down to 93% of its current speed. It then attempts to increase the rate by 4% (making it 97% of the initial transfer rate).
High: it would periodically (every 20 ms) attempt to increase the speed by 5% (for example, 105% of the current speed).