Bug ID 720075: LSN Translations may fail with 'LSN pick took too long' with NAPT mode and ipport cmp-hash

Last Modified: Apr 28, 2025

Affected Product(s):
BIG-IP CGN(all modules)

Known Affected Versions:
14.1.0, 14.1.0.1, 14.1.0.2, 14.1.0.3, 14.1.0.5, 14.1.0.6, 14.1.2, 14.1.2.1, 14.1.2.2, 14.1.2.3, 14.1.2.4, 14.1.2.5, 14.1.2.6, 14.1.2.7, 14.1.2.8, 14.1.3, 14.1.3.1, 14.1.4, 14.1.4.1, 14.1.4.2, 14.1.4.3, 14.1.4.4, 14.1.4.5, 14.1.4.6, 14.1.5, 14.1.5.1, 14.1.5.2, 14.1.5.3, 14.1.5.4, 14.1.5.6, 15.0.0, 15.0.1, 15.0.1.1, 15.0.1.2, 15.0.1.3, 15.0.1.4

Opened: May 14, 2018

Severity: 3-Major

Symptoms

Large Scale NAT (LSN) translations might fail when ipport cmp-hash is configured on the ingress and/or egress VLANs. LSN pick fails with LSN_ERR and failure-cause 'LSN pick took too long' on VIPRION B2150 blades, although any platforms may see failures or a decrease in performance.

Impact

Potentially, lower performance and failed connections.

Conditions

-- LSN pool in NAPT mode. -- ipport hash configured on ingress and/or egress VLAN. -- VIPRION B2150 blades.

Workaround

Configure the ingress/egress VLANs with either default or SPDAG.

Fix Information

None

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips