Efficiently and accurately estimating bandwidths in packet networks is a problem that has intrigued researchers for years. There is no simple manner for estimating bandwidths in IPv4 networks that is accurate, efficient, flexible, and suitable for a variety of applications. Many of the available estimation techniques suffer from inherent flaws such as inaccuracy due to simple assumptions about the network or an overall high complexity that makes it inappropriate in all but a few highly specific situations. The next generation Internet Protocol, IP version 6, has the functionality necessary to implement feedback mechanisms to assist in accurate bandwidth estimations. This thesis proposes a timestamp hop-by-hop option for IPv6 and then applies this option to create a new bandwidth estimation technique. Instead of passive observations, the network infrastructure actively assists in bandwidth measurements resulting in a bandwidth estimation technique that is accurate, efficient, flexible, and suitable for many different applications and scenarios. Both analytical and simulation analysis show that the IPv6 bandwidth estimation technique outperforms a comparable IPv4 estimation method.