STP Trunk Load Balancing

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Jan 29th, 2008
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Hi there, I'm trying to find out about load balancing between trunks with STP. I've read document 10555 which details how to load balance using port priorities if there are 2 switches connected to each other. I don't think this would work if the links were different speeds as it evaluates path cost to root before port priority.

What if there are switches that are not connected to each other directly? Is there a generally accepted method by using port cost to load balance as well port priority?



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s.arunkumar Tue, 01/29/2008 - 19:44
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Hi peter

If u are running multiple vlans(hence PVST)and u want to loadbalance then,its very well possible when the switches are directly connected also.Normaly switch will be running seperate stp instance for ecah vlan.So u can adjust the port cost or senders port priority vlaue to manipulate the STP topology for each instance and achive the load balancing,ie manipulate and make STP instance and make one port blocking for one vlan and another port for another vlan instance..


shrikar.dange Tue, 01/29/2008 - 20:11
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as arun said you can do load balancing by adjusting port cost/priority.But the other way to to do load balancing is using MST mode.

So you can have different set of vlans mapped to different instances.Have a particular switch as a root for set of vlans nad for other set of vlans use another switch as a root.



shri :)


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