Applying no ip address to an interface but applying a bridge group on it does not mean you are bridging IP.
IF "no ip routing" is turned on globally and you put a bridge group on an interface (with of without an ip address on it - that part doesn't matter) THEN you are bridging IP.
Let me try to explain.
There are basically 3 ways to tell if an interface is routing or bridging a protocol.
1) Global route/bridge of protocols
2) CRB
3) IRB
Let's talk about the first. If you have IP ROUTING and IPX ROUTING turned on under the global config section then IP and IPX will be routed ONLY regardless of whether you put IP or IPX addresses on interfaces. All other protocols that are not set under the global config section will be bridged under all interfaces that have bridging turned on. Putting an IP address on an interface doesn't
cause ip routing for that interface. Just as leaving one off does not let you bridge IP. This is decided globally with the routing commands.
2) CRB - concurrent routing and bridging. This allows you to have some interfaces where you will route IP and other interfaces where you will bridge IP. But the routed IP interfaces and the bridged IP interfaces will not communicate with one another in this box.
3) IRB - integrated routing and bridging. This is like CRB EXCEPT that it allows the bridged interfaces to communicate with the routed interfaces.
