ip routing command on C3750X Layer 3 switch stack

[rdoreleijers]

Hi guys/girls,

I need to add a routable layer 3 interface to a C3750X stack in a production environment.

Currently IP routing is not being used, and also not activated yet.

Will the "ip routing" command trigger any event that can interrupt network availability?

Model: WS-C3750X-24      
SW version: 15.0(2)SE6

Thanks!

[adawa]

Hello, rdoreleijers. 

Enabling "ip routing" without routing any specific specific addresses shouldn't be an issue and should cause no interruption on your network. I recommend backing up your IOS image just to make sure, before making any changes. Do you already have an IP Base software image downloaded on your 3750X? If not, you may still need to purchase the upgrade license from LAN Base or to IP Base/IP Services. 

Let me know if you have additional concerns or e-mail (adawa@cisco.com) me directly. Kind regards.  

[Richard Burts]

When you enable ip routing on the 3750 it will stop using its ip default-gateway command and will start expecting to find a route in its routing table for remote subnets and networks. The good news is that this will not affect its forwarding of layer 2 traffic. So if it is working fine now to forward user traffic then it will work fine after enabling routing for user traffic.

But enabling routing might affect your connection to the switch, especially if your connection to the switch is from a remote network. You should give some thought to whether this is an issue or not as you plan the implementation of routing on the 3750.

HTH

Rick

[Joseph W. Doherty · Accepted solution]

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Posting

BTW, I believe to deal with the issue Rick described, you can define a static default route to the same address as used by the default gateway, before you enable IP routing.

Also, as Adawa notes, you may need IP Base, or better, feature set image and license to activate IP routing.  (Licensing and feature set also have other considerations when working with a stack.)

[rdoreleijers]

Thank you all!