Port Channel Priority

[d front]

Can LACP priority help to make PO31 the active etherchannel over PO30 in my scenario? Image attached.

Both LACP are currently setup with default priorities.

Thanks!

Dan

[jdesanti]

No, what the LACP system priority actually does is, that the switch with the lowest system priority (a 2-byte priority value followed by a 6-byte switch MAC address) is allowed to make decisions about what ports actively are participating in the etherchannel at a given time. And the ports are selected based on the port priority.

By this LACP sets up to 8 ports to actively participate in the etherchannel, also please note that when setting the priority, a higher number means a lower priority.

[d front]

Thanks, so is there a way between switches to set priority on which port channel should be primary when a ring topology is used as in my diagram?

[jdesanti]

STP uses the port priority when selecting an interface to put into the forwarding state. You can assign higher priority values (lower numerical values) to interfaces that you want selected first and lower priority values (higher numerical values) that you want selected last.

Switch(config-if)# spanning-tree port-priority <0 - 240>

http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3850/software/release/3se/layer2/configuration_guide/b_lay2_3se_3850_cg/b_lay2_3se_3850_cg_chapter_010.html#concept_2585CE88E3CC4A759EBA8AB9524A3E2A

[d front]

I found the solution.

I had to setup the router I wanted to have the active port-channel to a higher MST priority.

Originally the router with that I wanted to have priority had a priority of 8192 and the other had 4096.  I switched their priorities and now it's working as I wanted.