I work at a digital TV broadcast company (cable), we have 2 head ends, one in the US and one in the Caribbean, we currently connect both sites with a cisco L2TPv3 pseudowire VPN between both sites, however, because we're running video streams over this pseudowire using RTP (UDP) on a multicast address; if/when packets take different routes across the internet and come out of order to the receiving end, my MPEG transport streams will have continuity count errors (and the PIDs within them might have customer affecting artifacts).

Because of the above issue, I'm looking to replace the pseudowire with some other VPN technologies that reorders packets that come in out of sequence, but I'm not sure what alternatives are available (if any). My question is then, what strategy or technology can I use to minimize the impact of the problem described above?


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I never used RTP but AFAIU, your should probably increase the buffering/latency on the receving side at the RTP level: the RTP has a timestamp packet which can be used to reorder the packets.

If you have lost packets, it won't help you however.

If you try to solve the problem by enfocring datagrams/packet ordering at a lower level in the protocol stack (for example by using TCP for transporting either the RDP of the VPN), you will suffer of HOL blocking: instead of losing the some part of the stream when packets are dropped, the receiving side will have to wait for the packets to be retransmitted and arrive (i.e. the stream will pause).

See Head-of-Line-Blocking in Transport Protocols.

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