The traffic of backbone networks grows at an accelerated rate, which makes the design strategies and capacity definitions two key elements for the implementation of this type of networks nowadays. The biggest challenge that the services providers are facing is the reduction of costs and the creation of new added value, which raises the offer to the final client. The traffic of the biggest networks is still based on SONET/SDH equipment. This technology has not experience any significant changes and it has only evolved in the ability to cover the high levels of traffic demand. Because of this, the IP/MPLS networks appear, gaining importance in a critic and demanding environment.