Bug ID 624016: Traffic data stats get lost on hardware-accelerated flows when the flows are terminated earlier

Last Modified: Oct 24, 2019

Bug Tracker

Affected Product:  See more info
BIG-IP LTM(all modules)

Known Affected Versions:
12.1.0, 12.1.0 HF1, 12.1.0 HF2, 12.1.1, 12.1.1 HF1, 12.1.1 HF2, 12.1.2, 12.1.2 HF1, 12.1.2 HF2, 12.1.3, 12.1.3.1, 12.1.3.2, 12.1.3.3, 12.1.3.4, 12.1.3.5, 12.1.3.6, 12.1.3.7, 12.1.4, 12.1.4.1, 12.1.5, 13.0.0, 13.0.0 HF1, 13.0.0 HF2, 13.0.0 HF3, 13.0.1, 13.1.0, 13.1.0.1, 13.1.0.2, 13.1.0.3, 13.1.0.4, 13.1.0.5, 13.1.0.6, 13.1.0.7, 13.1.0.8, 13.1.1, 13.1.1.1, 13.1.1.2, 13.1.1.3, 13.1.1.4, 13.1.1.5, 13.1.3, 13.1.3.1, 14.0.0, 14.0.0.1, 14.0.0.2, 14.0.0.3, 14.0.0.4, 14.0.0.5, 14.0.1, 14.0.1.1, 14.1.0, 14.1.0.1, 14.1.0.2, 14.1.0.3, 14.1.0.4, 14.1.0.5, 14.1.0.6, 14.1.2, 14.1.2.1, 15.0.0, 15.0.1

Opened: Oct 20, 2016
Severity: 3-Major

Symptoms

When the clients tend to reset HTTP keep alive connections immediately after data is received, instead of gracefully closing the connections per RFC, and because these flows were reset, the system loses these packet stats for the offloaded flows. This occurs because the BIG-IP system cannot determine the traffic direction without the connection flow information. FIN packets experience the same effect of closing the connection. If there are Flow Status Updates (FSUs) after the FIN packets, they are not counted either.

Impact

PVA traffic stats may not accurately show the packets/bytes counts for the offloaded flows.

Conditions

Clients that reset connection immediately after data is received.

Workaround

One workaround is to consult with the hardware ePVA packet and byte forward counters in addition to the global PVA traffic stats. For verification purposes, you can use the following command: # tmctl -d blade -s name,active,bus,rqm_epva_fwd_pkts,rqm_epva_fwd_bytes tmm/hsbe2_internal_pde These rqm_epva_fwd_pkts/bytes counters are the current hardware counters from the ePVA registers, which are more up to date. Note: Make sure to associate the lbb_pde number to the individual PVA numbers in the output of 'tmsh show sys pva-traffic'. To get the global stats for all PDEs (as in 'tmsh show sys pva-traffic global'), you must use a script to add up these numbers.

Fix Information

None

Behavior Change