Multimedia streaming applications have been increasing significantly due to the rapid growth of broadband access networks. Among the latest real-time streaming technologies, the scalable video coding (SVC) which is a layered coding scheme attracts more attention. The SVC encodes an original video into several streaming layers of different bit rates simultaneously. Thus, clients can subscribe a part of the coded layers of SVC video according to their available bandwidth, which should be measured by a bandwidth estimation methodology. Additionally, in SVC clients can augment or abate the number of subscribed streaming layers to fit the time-varying bandwidth during viewing programs. In this paper1, we exploit the concepts of Traceroute and ICMP timestamps to design a two-way available bandwidth estimation mechanism which is never presented in literature. The proposed scheme can infer the available bandwidth of both uplink and downlink paths, and is feasible to the paths with multiple tight links. Hence, it is specially applicable to the multimedia streaming applications adopting SVC. Numerical results show that the presented bandwidth estimation approach can achieve good accuracy.