2921 "team" ethernet ports

[curtmcgirt]

i would like to "team" two ethernet ports on a 2921 router into a single redundant link to a switch, similar to how an HP server teams multiple NICs to a single IP address. is port-channeling the best/only way to do this? i don't necessarily need the two links to be load balanced or bonded, considering the serial side of this router is just a single T1. i just want the links redundant, so in case something goes wrong with one cable or switchport, traffic will go over the other link.                  

[Joseph W. Doherty]

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The   Author of this posting offers the information contained within this   posting without consideration and with the reader's understanding that   there's no implied or expressed suitability or fitness for any purpose.   Information provided is for informational purposes only and should not   be construed as rendering professional advice of any kind. Usage of  this  posting's information is solely at reader's own risk.

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Posting

For redundancy, it's not the only way.  You could also use your two Ethernet ports as routed links or you might bridge across them.

As which method is "best"; much depends on what you're connecting to and its capabilities.

[curtmcgirt]

thanks Joseph. in this case i'm connecting the 2921 to a single 3750 switch. in a separate site i'm planning to connect one interface each to two stacked 3750s. i think bridging sounds like the way to go. with bridging do i have to configure anything special on the switch side, other than the appropriate vlan on the switchports? 

https://supportforums.cisco.com/thread/209282

[Joseph W. Doherty]

Disclaimer

The  Author of this posting offers the information contained within this  posting without consideration and with the reader's understanding that  there's no implied or expressed suitability or fitness for any purpose.  Information provided is for informational purposes only and should not  be construed as rendering professional advice of any kind. Usage of this  posting's information is solely at reader's own risk.

Liability Disclaimer

In  no event shall Author be liable for any damages whatsoever (including,  without limitation, damages for loss of use, data or profit) arising out  of the use or inability to use the posting's information even if Author  has been advised of the possibility of such damage.

Posting

I think that would be sufficient on the switch side.  However, personally I would lean toward the teaming approach as fail over will be faster than STP.

[Richard Burts]

You do not need to do anything on the switch side other than making sure that both switch ports are in the same vlan and have similar configuration parameters.

On the router side it is more complex that just turning on bridging. What you need to do is to use IRB and the link that you posted is a very good description of how to do that.

HTH

Rick

[curtmcgirt]

if i use bridging, won't uplinkfast make the failover pretty much instant?

[ROBERTO TACCON]

Understanding Layer 3 EtherChannel Support on the Cisco ISR

http://www.cisco.com/en/US/prod/collateral/routers/ps5855/prod_white_paper0900aecd806f698a.pdf

HTH