I can confirm that GTT does indeed filter IP sourced from 224.0.0.0/4 at its edge.
On 7/31/2018 6:44 PM, Patrick W. Gilmore wrote:
It is hard to prove a negative. So let’s prove a positive. One of the largest (2nd largest?) transit networks on the planet just affirmatively stated they filter at their border. It is now possible to state that multicast is not ubiquitous on the Internet. If any other large transit network (L3, GTT, HE, Cogent, etc.) would like to confirm they filter at their borders as well, that would put the final nail in the coffin.
