Solved: LACP partner's port state 0X3D or 0X3F ?

kerim mohammed · ‎02-21-2012

Hi all,

I was troubleshooting vPC operation betwenn Nexus 5K cluster and a server. Below is the output i got and i couldn't understand the partner port state field. can somebody help me with this? to be specific what is the difference between partner port state= 0X3d and 0X3f. I attached the command output from the nexus 5k switch.

Steve Fuller · ‎03-08-2013

Hi,

I found your post while trying to find this information for myself, and as I've now found the answer and this post comes near the top of an Internet search, I thought I'd put the answer here.

The difference between 0x3D and 0x3F is the rate of the Link Aggregation Control Protocol (LACP) Protocol Data Unit (PDU). In your example the partner connected via port-channel 12 with a port state of 0x3F is requesting the LACP PDU be sent at 1-second intervals, and the partner connected via port-channel 14 with a port state of 0x3D is requesting the LACP PDU be sent at 30-second intervals.

This information is specified within the IEEE 802.1AX standard (previously IEEE 802.3ad) in clause 5.4.2.2 as part of the Actor_State field. In the standard the 1-second interval is called the Short Timeout and the 30-second interval is called the Long timeout. On Cisco switches this is configured under the physical interface with the lacp rate {normal|fast} command.

The same clause of the standard specifies the meaning of the other bit values within the Actor_State field in case you need to determine the meaning of those as well.

Hope that helps.

Regards

View solution in original post

Steve Fuller · ‎03-08-2013

Hi,

I found your post while trying to find this information for myself, and as I've now found the answer and this post comes near the top of an Internet search, I thought I'd put the answer here.

The difference between 0x3D and 0x3F is the rate of the Link Aggregation Control Protocol (LACP) Protocol Data Unit (PDU). In your example the partner connected via port-channel 12 with a port state of 0x3F is requesting the LACP PDU be sent at 1-second intervals, and the partner connected via port-channel 14 with a port state of 0x3D is requesting the LACP PDU be sent at 30-second intervals.

This information is specified within the IEEE 802.1AX standard (previously IEEE 802.3ad) in clause 5.4.2.2 as part of the Actor_State field. In the standard the 1-second interval is called the Short Timeout and the 30-second interval is called the Long timeout. On Cisco switches this is configured under the physical interface with the lacp rate {normal|fast} command.

The same clause of the standard specifies the meaning of the other bit values within the Actor_State field in case you need to determine the meaning of those as well.

Hope that helps.

Regards

Peter Paluch · ‎03-08-2013

Hi Steve,

Very nice and informative answer!

Best regards,

Peter

kerim mohammed · ‎03-08-2013

HI Steve,

Thanks for sharing! But i don't understand why one wants to use fast mode? it is a burden on the CPU and you can't do ISSU (non-disruptive upgrade) on the nexus if you set it to fast mode. But again thank you you very much for sharing.