In spanning-tree, lower is always better. Lower priority, lower MAC address, lower root cost. Lower always wins.
So to decide between two ports between the same two switches, the port priority and the port number are used. Since the default port priority is always 128, that means that by default the lowered numbered port will win. Much like the bridge priority and MAC address, tweaking the port priority totally overrides the port number. One thing, though... With an Etherchannel, the individual member ports no longer participate in spanning tree directly. The network sees the logical port-channel as the STP interface. You can't influence which member of an Etherchannel is preferred with respect to spanning tree, it's a moot concept. The EC has to hash flows onto various member ports without worrying if one of them is blocking, so the STP port function is done by the logical port-channel interface. Depending on your task, it's possible it was referring to the LACP port priority which is how LACP might decide which ports are active and which ports are in hot-standby if more than 8 ports are defined in an LACP Etherchannel. In that case, lower still wins (again, for LACP, lower always wins), but it's not the spanning tree commands to set that value. Hope that helps! On Sat, Feb 2, 2013 at 12:26 AM, robert shepherd <[email protected]>wrote: > I get confused on the spanning-tree port-priority command at the interface > level > and want to get clairification. > For example: > Fa0/19 - 20 are configured in an ether-channel. > Make sure that port 19 is preferred over port 20. > > spanning-tree port-priority 0 > spanning-tree port-priority 240 > > In other words is lower value better or worse? > > On a side note. This forum, staff and contributors are great. I am > counting down at this > point to my 1st lab attempt. Less than 3 months and counting. > _______________________________________________ > For more information regarding industry leading CCIE Lab training, please > visit www.ipexpert.com > > Are you a CCNP or CCIE and looking for a job? Check out > www.PlatinumPlacement.com > > http://onlinestudylist.com/mailman/listinfo/ccie_rs > _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com Are you a CCNP or CCIE and looking for a job? Check out www.PlatinumPlacement.com http://onlinestudylist.com/mailman/listinfo/ccie_rs
