Cisco Etherchannel Configuration

I never seriously thought I would be blogging on how to configure Cisco devices, much less the advanced portions of the Cisco devices... but work has a funny way of making you learn things you never thought you would.

The site I am configuring has a HP blade enclosure with two Cisco Switches serving up the blades' primary and secondary ethernet connections. Right now, those switches have a single physical ethernet connection back to the core switch of the network (that way if one switch in the enclosure fails, the other takes over). We want to increase the bandwidth available between that blade center and the core switch because we are planning on filling up that blade center.

In addition, we have added a new core cisco switch as a fail over switch for total hardware redundancy up to the firewall. These two switches need to talk to eachother to pass traffic in the event that one goes down.

Enter Etherchannel, which aggregates single network connections on switches into a single logical connection with the combined bandwidth of both.

This is the site I used for configuring my switches: http://jklogic.net/cisco-ios-to-catos-etherchannel-configuration/

It gives a good understanding of what the tasks are at hand, but there are a few additional steps required to really get it going, and after confirming with a Cisco representative, this is what I ended up with for configuration:

Of the Cisco IOS flavor (cisco 3560G specifically, running 12.2):

...
!
interface port-channel1
switchport trunk encapsulation dot1q
switchport mode trunk
!
...
!
interface GigabitEthernet0/47
switchport trunk encapsulation dot1q
switchport mode trunk
channel-group 1 mode on
!
...

And of the CatOS variety (specifically the Cisco 2948G-GE-TX) we get:

...
!
#port channel
set port channel 2/47-48 20 (note that the 20 is an ID and is optional)
!
...
!
set trunk 2/47 nonegotiate dot1q (extra stuff about vlans)
set trunk 2/48 nonegotiate dot1q (extra stuff about vlans)
set port channel 2/47-48 mode on
end

At this point, you can connect the physical cables and you should have a working etherchannel. It looks deceptively easy written down... but this took like 6 hours to work out on the phone with Cisco.

For connecting IOS to IOS, just do the first IOS part on both devices... for CatOS to CatOS... you get the point.