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New Member

Load-balancing without Etherchannel

I need configure 3 GE links between 2 switches, all active at same time.

I need configure load-balancing traffic between switches almost manually

I need InterVLAN routing passing from the first box to the second box and viceversa.

The first box have attached several layer 2 switches with 2 subnets, in the second box exists the same scenario, with different subnets obviously, finally both switches have PCs and servers assigned to one common VLAN. Is necessary stablish communication between hosts in different subnets, in different boxes, and between equipments in the same VLAN.

Please suggest me a configuration

My equipment:

The first box is Cat 5509 SupIII, with RSM, with WS-X5403 (3 GE ports without hardware support for Etherchannel)

The second box is Cat 4507R with SupIV with WS-X4306-GB (6 GE ports)

In both boxes I will use 1000Base-SX GBICs

Thanks in advance

New Member

Re: Load-balancing without Etherchannel

IF you enable the three connections at the same time without etherchannel STP will shut two of them down.


set each Gig connection to its own vlan then add each vlan to each route module.

You will then be able to load balance at layer three (depending on your route protocol)

Problem.. You will then loose any ability to use HSRP or redundant uplinks to these switches.

Depending on your topology, these may not be available anyway.


New Member

Re: Load-balancing without Etherchannel

You can apply STP accross Vlans, this is one of the features that probably makes Cisco Systems the leaders in networking. You can assign a root path cost for each VLAN (subnet) so that for example GE link 1 will be forwarding for Vlan1 and Vlan2 while it will also be blocking for VLAN3 and VLAN4, GE link2 can be blocking for VLAN1 and VLAN2 while forwarding for VLAN3 and VLAN4. Note that all the GE links are trunk ports and carry all VLANS, but not all of them will be in the forwarding state by the STP. Commands like : "set spantree portvlancost 3/1 cost 1 vlan 1-2" on the 5000 series, or the "spannig-tree vlan 1 cost 100 " on the 4507 can be helpful.

Please refer to the STP configuartion guide

Good luck

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