Bug ID 428467: max-concurrent-udp/max-concurrent-tcp maximum values

Last Modified: Sep 13, 2023

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

Known Affected Versions:
11.2.0, 11.5.0, 11.5.1, 11.5.2, 11.5.3, 11.5.4, 11.5.5, 11.5.6, 11.5.7, 11.5.8, 11.5.9, 11.5.10, 11.6.0, 11.6.1, 11.6.2, 11.6.3, 11.6.3.1, 11.6.3.2, 11.6.3.3, 11.6.3.4, 11.6.4, 11.6.5, 11.6.5.1, 11.6.5.2, 11.6.5.3

Opened: Aug 21, 2013

Severity: 2-Critical

Symptoms

If the max-concurrent-udp/max-concurrent-tcp dns cache parameters are set too high for the platform, the memory needed to fulfill the request may cause tmm to panic.

Impact

When this occurs, tmm can core.

Conditions

This occurs because tmm creates max-concurrent-tcp communication points, each of which has a 64 KB buffer. For example, 8 tmms at 64 KB each results in approximately 500 KB for a single communication point. When multiplied by 2 billion, there will be problems with memory allocation.

Workaround

None

Fix Information

None

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips