On 11/02/2013 12:16, Aled Morris wrote:
I don't see why, as an ISP, I should carry multiple, identical, payload packets for the same content. I'm more than happy to replicate them closer to my subscribers on behalf of the content publishers. How we do this is the question, i.e. what form the "multi"-"casting" takes.
It would be nice if we could take advantage of an inherent design of IP and the hardware it runs on, to duplicate the actual packets in-flow as near as is required to the destination.
Multicast is fine when it works, which is generally only in systems where the operator has end-to-end control of the entire data path, where the number of streams isn't too large that the middleboxes have trouble handling all the state requirements, where the middleboxes all support multicast adequately without causing collateral problems, and where the end point talks the same version of multicast as the source, where you don't run into weird vendor multicast bugs and where you don't have packet loss on any intermediate systems. When it stops working, level 3 engineering will usually be able to get it fixed, given enough time, resources and support from vendors. If you're ok about having escalation level engineering dealing with front-line multicast support issues for customers paying a tenner a month, then I wish you well :-) Nick