What occurs when a high bandwidth multicast stream is sent over an MVPN using Cisco hardware?

While traffic initially uses the default MDT, high-bandwidth (S,G) streams are typically switched to a Data MDT to avoid flooding. The default MDT carries all MVPN control traffic and low-bandwidth data, not just (S,G) traffic.

Data MDTs are primarily created for source-specific (S,G) multicast route entries to optimize their path, not for `(*,G)` (shared tree) entries, which usually remain on the default MDT.

A Data MDT is created to avoid flooding high-bandwidth streams to all PIM-SM neighbors, offering a more selective path, whereas the default MDT is designed for broader distribution, including control plane traffic.

In MVPNs, a Data MDT (Multicast Distribution Tree) is dynamically created to carry high-bandwidth, source-specific (S,G) multicast streams. This process offloads the stream from the default MDT and provides a more optimized, pruned path through the MPLS core, preventing unnecessary flooding to all Provider Edge (PE) routers and improving transmission efficiency.