Trunking between Cisco 3750 and other switches

[g.brown]

I would like to setup a trunk or aggregate link between a Cisco 3750 and some 3Com Baseline 2848 SFP switchs. The 3Com's let you trunk ports together but I dont see in the Cisco where I can do something like that.

Any ideas if this is possible or not?? The Cisco is the main backbone switch with the 3Com's being in the same closet. I am already using teh SFP ports on the Cisco to connect up my other IDF's. Tk.

[glen.grant]

If you mean bundling ports together then yes you can do that , you have to create a trunk/etherchannel to bundle the ports together on the 3750 . Create the etherchannel then you put the trunk commands under the port channel interface .

[g.brown]

Would it be possible to do that with the SFP Ports as well??

That is what I would like to trunk since I have a single mode fiber running to another building that is 660 yards away. I have 12 strands and would like to trunk 2 SFP ports together for 2Gig links.

[tjblue · Accepted solution]

To implement an ether-channel as glenn had mentioned, you could do the following. This would make the link a dot1q trunk, in addition to bundling them as an etherchannel link.

The port-channel interface will not exist until you create it. [router#(config) interface port-channel1]

# EXAMPLE ETHERCHANNEL CONFIGURATION #

#

!

interface Port-channel1

switchport trunk encapsulation dot1q

switchport mode trunk

!

#

# EXAMPLE TRUNK CONFIG FOR ETHERCHANNEL CHANNEL GROUP #

#

!

interface GigabitEthernet1/0/1

switchport trunk encapsulation dot1q

switchport mode trunk

no keepalive

channel-group 1 mode on

!

interface GigabitEthernet1/0/2

switchport trunk encapsulation dot1q

switchport mode trunk

no keepalive

channel-group 1 mode on

[jlkeys]

Why would you want to disable the keepalive signals on the two physical interfaces?

Without the keepalives enabled, wouldn't the two switches have problems communicating across the port-channel if one of the links failed?