Port-Channels vs. Sub-interfaces

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Jun 27th, 2007
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Can anyone tell me if there's any reason why one would create a Port-Channel (containing only a single member) vs. a routable sub-interface? The device type is a 2948GL3.

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caseth0102 Wed, 06/27/2007 - 10:44
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Hi and thx for the reply. So in other words, the person who made this config, used a PO to handle the routing of the connected subnet, vs. just creating a subinterface of the physical port..correct? <

caseth0102 Wed, 06/27/2007 - 11:01
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Krisztian this unit is a 2948GL3 (routable) and is currently my core. I am trying to simply the new config with what makes sense. To me it appeared as if the PO was created simply to hold an ip, and to be used as the DFG instead of configuring a sub-int. I just want to make sure there is nothing i am missing moving forward. I plan to rip out all PO's with only a single member and configure the new core with routable interfaces (sub-ints) vs. carrying over a sloppy design.

Wilson Samuel Wed, 06/27/2007 - 10:57
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I guess this might be looking the future aspect, and modularity, i.e. if required multiple FE ports or GE ports could be added to the Port-Channel and it is more scalable (in terms of BW and fault-tolerance)

Now in terms of the Subinterface this can't be done in order to handle if the need for bandwidth grows high.

I hope that helps,

Please rate if it helps,

Kind Regards,

Wilson Samuel


I have to agree with Wilson, that the PO does not have disadvantage and if you plan to increase the bandwidth the PO is a good choice. Anyway you have two way to create L3 interface. The first is to configure the switchport with ip address i.e. make it routable interface (obviously if you have trunk interface it is not possible) or create an SVI and assign the L2 port to that vlan. Summarized you don't need to get rid of the PO.



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