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Oracle Linux: Mellanox ConnectX-5 Ethernet Adapter Not Receiving Packets Larger than Its MTU (Doc ID 2961459.1)

Last updated on JULY 29, 2023

Applies to:

Linux OS - Version Oracle Linux 7.0 and later
Linux x86-64

Symptoms

If the Mellanox ConnectX-5 ethernet adapter receives a packet in which the ethernet frame payload is larger than the NIC's MTU, the packet is discarded.  This behavior may arise confusion since MTU impacts network packets transmission by its definition.

It can be monitored and verified by checking the ConnectX-5 ethernet driver(mlx5_core.ko) specific counter "rx_oversize_pkts_sw_drop",

Above "rx8" means number 8 receiving ring buffer of the interface.

Changes

Changing MTU to a smaller size on Mellanox ConnectX-5 Ethernet adapters.

Cause

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In this Document
Symptoms
Changes
Cause
Solution


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