Mellanox Path MTU value not showing as per spec


When we receive Connect request , the MDA packet payload (PMTU) showing value as 0. Some time it is showing as 7.

But as per the spec the valid values are as fallows.

Mtu 6 434 Enumeration of the MTU required:

1: 256

2: 512

3: 1024

4: 2048

5: 4096

0,6-63: reserved

Hi Muki,

My query is what is significance of PMTU field in Connect Reqeust field. To set the PMTU you are referring with ifconfig command. What ever the MTU value we are setting ifconfig command will it reflect in Connect request field PMTU field




Hi Rama,

Does this question is RDMA or IPoIB related?


Hi Rama,

Please check the following like

Can you print the output of the problem?

What is the driver version and adapter that in use?

how is the setup looks like?