ltm rule command TCP snd ssthresh

iRule(1)					  BIG-IP TMSH Manual					     iRule(1)

TCP::snd_ssthresh
       Returns the TCP slow start threshold (ssthresh).

SYNOPSIS
       TCP::snd_ssthresh

DESCRIPTION
       The slow start threshold (ssthresh) is the point at which the congestion window (cwnd) grows less
       aggressively. When the cwnd is less than ssthresh, it roughly doubles for every cwnd worth of acknowledged
       data. When cwnd is greater than ssthresh, it increases by approximately one MSS for each cwnd worth of
       acknowledged data.

       ssthresh starts at 1,073,725,440 bytes unless there is a cmetrics cache entry. When TCP detects packet loss it
       usually sets ssthresh to a value between 1/2 cwnd and cwnd, depending on  connection conditions and the
       congestion control algorithm.

RETURN VALUE
       The connection slow start threshold in bytes.

VALID DURING
       ANY_EVENT

EXAMPLES
	when CLIENT_ACCEPTED {
	    # Get BIGIP's initial slow-start threshold.
	    log local0. "BIGIP's ssthresh: [TCP::snd_ssthresh]"
	}
	when CLIENT_CLOSED {
	    # Get BIGIP's last slow-start threshold.
	    log local0. "BIGIP's ssthresh: [TCP::snd_ssthresh]"
	}

HINTS
SEE ALSO
CHANGE LOG
       @BIGIP-12.0.0 --First introduced the command.

BIG-IP						      2020-06-23					     iRule(1)