Backup Interface - Alternate Solution

[taro75]

I have been using Cisco 3800 series switch and backup interface commands (flex links).

switchport backup interface <interface-id> to designate a standby port to define failover behavior. 

I am replacing these switches with 9300 series, and the previous backup interface is no longer available. How can I achieve the same functionality for L2 redundancy on this new series switches. I can not user LACP because I have no control on the other side of the network.

[Kasun Bandara]

Hi @taro75 try below solution if its the requirement you are looking for

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9300/software/release/17-9/configuration_guide/lyr2/b_179_lyr2_9300_cg/configuring_flexlink_.html

[taro75]

As per the link, it's supported on  trunk ports and port channel. Is it supported on Access Ports?

[Cristian Matei]

Hi,

 @taro75 Flexlink adds unnecessary complication in my view, with REP requirements and based on the overall topology you might run into various unexpected behaviours.

    My strong recommendation is to have both interfaces configured the same way and use two EEM scripts: one to activate secondary link when primary fails, and another one to activate primary link when secondary fails. 

Thanks,

Cristian.

[balaji.bandi]

I agree what @Kasun Bandara  suggested here.

 I have no control on the other side of the network.

then you need to check the compatability what other side device can work as expected when you move to flexlink+