Last Modified: Sep 13, 2023
Affected Product(s):
BIG-IP LTM
Fixed In:
17.0.0, 16.1.2.1, 15.1.5, 14.1.4.5, 13.1.5
Opened: Apr 28, 2021 Severity: 3-Major
If a long tail loss occurs during transmission, TCP might be slow to recover.
BIG-IP retransmits one packet per RTT, causing a long recovery. The impact is more pronounced if an entire window is lost.
-- A virtual server is configured with the TCP profile attached. -- SACK and TLP are enabled. -- A tail loss of multiple packets sent by the BIG-IP occurs.
Disabling TLP may improve performance in this particular case, but may degrade performance in other situations.
A new sys db key was added: tm.tcpaggressivepartialack (disabled by default). When enabled, more data is retransmitted every RTT, similar to slow-start.
A new sys db key was added: tm.tcpaggressivepartialack (disabled by default). When enabled, more data is retransmitted every RTT, similar to slow-start.