EIRGP, Bandwidth and Delay Detection

Hello all,

I have been asked the question does EIGRP dynamically detect physical bandwidth and delay of a link or must the figures be manually entered during the router configuration.

I have been informed that it can for interfaces such as fibre and ethernet but not for serial interfaces but cannot find any reference in any cisco documentation to back this up.

I would appreciate any information that is provided.

Thanks in advance

Stephen.