hi alsayed,

First of all, You need to run across this link.

http://www.cisco.com/en/US/netsol/ns818/networking_solutions_program_home.html

IMHO, You can use CCME to accomplish this requirement. If you have a plan to increase more ip phones then you should deploy CCM in your network. CCME is enough in your case. You have to purchase ISR Router that supports CCME to do so.

RIB failure is telling you that the router has already installed the same route with a better administrative distance in the routing table. Let's check by using "show ip route".

Toshi