Catalyst switches - what does "ip routing" actually do?

[vv0bbLeS]

Hello all,

After setting up countless Catalyst switches (3560's, 9k's, etc.), I realized I'm still confused on what the ip routing command "actually" does on a Catalyst switch - does it:

1. Enable the switch to route traffic between SVI's on the switch itself?
2. Enable the switch to use routing protocols?
3. Enable some kind of routing process(es) on the switch?
4. Change the RIB structure in any way?
5. Maybe some/all of those things, or maybe even more things?

I ask because it seems like the Catalyst switch can do L3 things before I run ip routing - but I'm not sure what extra abilities the switch gets when I run that command?

[MHM Cisco World · Accepted solution]

Before the ip routing 

You can add IP to vlan svi

Ypu can use default gateway 

Ypu can't use static nor IGP 

After ip routing 

All above ypu can do

MHM

[vv0bbLeS]

@MHM Cisco World gotcha, so ip routing just enables the use of static routes and all routing protocols? That makes sense, as I have a Cat 9300 next to me that doesn't have ip routing enabled , and I can't enable a routing protocol on it. Also I'm able to add static routes but they don't show up in show ip route . Thank you!

If anyone else has anymore information on the ip routing command I'd love to hear it!  : )