Requirements for direct media between StarLeaf endpoints
Managing StarLeaf platform and traffic routingLast updated February 27, 2020
When routing the media (audio, video, and content) for a call, StarLeaf ensures that the traffic uses the most direct route. A direct route means that the media uses the shortest, lowest latency media path possible between the two endpoints and avoids unnecessary usage of the organization’s Internet connection.
There are two types of direct media described here: Private Direct Media and Public Direct Media.
- Both Public and Private Direct Media are only available in point-to-point calls between StarLeaf manufactured soft or hard endpoints
- In an ad hoc or scheduled conference, all media is routed via the StarLeaf platform
- Point-to-point calls involving H.323, SIP, or Lync endpoints route all media via the StarLeaf platform
Private Direct Media describes the situation where both StarLeaf endpoints are behind the same firewall. In this case, media is sent directly between the two endpoints. The direct route avoids unnecessary usage of the organization’s Internet connection. The signaling traffic represents only a tiny amount of data, by comparison.
- A layer 3 UDP routable path must be available between the two StarLeaf endpoints
Public Direct Media describes the situation where both StarLeaf endpoints are behind NAT devices A and B respectively. In this case the media for the call is routed across the public Internet by the most direct route and is not routed through StarLeaf.
- Both endpoints must be connected to the StarLeaf platform via UDP tunnel
- The NAT device must match one of the following:
- Full-cone NAT. This is where NAT A uses the same public IP and port number for all packets sent from a given internal IP and port number, and forwards all packets received on that public IP and port number to this internal IP and port number. This must happen regardless of their source IP and port number. NAT B can be of any type in this scenario
- Address/Port restricted cone NAT. This is where both NAT A and NAT B use the same public IP and port number for all packets sent from a given internal IP and port number. However, either or both NATs must only forward packets from the remote IP and port number from which a packet has previously been sent
- In practice, Public Direct Media generally works when either or both of the NAT devices are domestic DSL routers, but generally does not work when both NAT devices are corporate firewalls