EtherChannel Across Multiple Slots

[bbeach001]

The examples I have seen for EtherChannel always bundle multiple ports on the same slot.  It seems that bundleing ports across multiple slots would increase the resilency.  For example when linking two core switches together.  I assume this would allow the link to stay up if the card in a given slot failed.  Is this supported?  If so, are there any concerns?   

[Elton Babcock]

You are correct. I have always assumed it to common practice to bundle your ports across slots and even redundant chassis.

Same thing goes for stacked switches such as a 3750.

Elton

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[Leo Laohoo]

The examples I have seen for EtherChannel always bundle multiple ports on the same slot.

The concept of EtherChannel has been an old concept since the beginning.  And as such, documentation has not been kept updated.  The only difference is the added concept of logical and physcial switch.

To an un-initiated a stack of 3750 switches is a physcial switch but to a switch, it's a logical switch.  Same goes with a 6500 or a 4500.  Throw VSS into the mix and you can still "extend" etherchannel.  You can have a single Nexus 5000 Etherchannel/VPC into a VSS pair of 4500R+E or a VSS pair of 6500. 

[Joseph W. Doherty]

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Posting

It seems that bundleing ports across multiple slots would increase the resilency.  For example when linking two core switches together.  I assume this would allow the link to stay up if the card in a given slot failed.  Is this supported?  If so, are there any concerns?    

Across slots is indeed done to increase resiliency.

Concerns?  Yes, on some chassis, different cards may have different QoS architectures.  You may have to configure platform to ignore this.  Also, you can channel across different media (fiber and copper).

At least on 6500 VSS, ingress traffic will use same 6500 egress link (this to avoid transiting VSL).