Bug ID 1022997: TCP segments with an incorrect checksum are transmitted when the sock driver is used in AWS deployments (e.g., 1NIC)

Last Modified: Jun 10, 2021

Bug Tracker

Affected Product:  See more info
BIG-IP LTM(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, 15.1.0, 15.1.0.1, 15.1.0.2, 15.1.0.3, 15.1.0.4, 15.1.0.5, 15.1.1, 15.1.2, 15.1.2.1, 15.1.3, 16.0.0, 16.0.0.1, 16.0.1, 16.0.1.1

Opened: Jun 03, 2021
Severity: 3-Major

Symptoms

Deployments on AWS that use the sock driver (1NIC, for example) transmit packets with bad checksums when TSO/GSO is required. This causes significant delays as TMM re-segments the packets with correct checksums for retransmission, and may cause some operations to time out (such as configsyncs of large configurations).

Impact

-- Delayed packets. -- Possible timeouts for some operations (configsyncs, for example).

Conditions

-- BIG-IP Virtual Edition (VE) using the sock driver on AWS (all 1NIC deployments use this) -- TSO/GSO required due to MTU limitations on one or more VLANs

Workaround

Modify (or create, if not present) the file /config/tmm_init.tcl on the affected BIG-IP systems, and add the following line to it: ndal force_sw_tcs off 1d0f:ec20 Then restart TMM: bigstart restart tmm Note: Restarting TMM will cause a failover (or an outage if there is no high availability (HA) peer available).

Fix Information

None

Behavior Change