You created this thread in Feedback Forum, which is inappropriate. Then you moved it to Small Business Routers - but 3945 is not SMB router, thus question is off-topic here as well. Please move it to WAN, Routing and Switching
By the way, you should disclose why you wish the "sh ip int bri" should display somethink. Because simplest answer to your question is - there is just nothing to display.