HAPI over WAN and Unicast

Official discussion forum for the Merging range of networkable converters
Forum rules
The Merging Technologies team cannot be held responsible for support queries logged on the public forums. If a support query is logged here and only here, it may not be found and dealt with by the appropriate team.
To ensure that your support issue or bug report is dealt with properly and in good time, please use the link to the tech support request form page on the Merging website.
Make sure to let us know what version you are using when you send your mail. THANKS!
tiborknowles
Posts: 23
Joined: Sun Oct 26, 2014 04:41

HAPI over WAN and Unicast

Postby tiborknowles » Fri Mar 15, 2019 16:35

Hello,

Doing a design and would like to hook up two HAPI's or Anubis over AWS or Google Cloud Platform.
Has there been any testing done regarding HAPI over WAN?

Essentially, the ports targeting the WAN would need to be Unicast. How would the PTP packtes handle that?

Please let me know at your earliest convenience.

Thanks, Tibor

tiborknowles
Posts: 23
Joined: Sun Oct 26, 2014 04:41

Re: HAPI over WAN and Unicast

Postby tiborknowles » Fri Mar 15, 2019 23:28

1. Would it be necessary to have a PTP Grandmaster clock locked to GPS in both locations?
2. Would ANEMAN pick up both HAPI's (assuming they both need to be on same subnet?)
3. What if the HAPI were not on the same subnet, how would you get them talking? NAT?
4. Can you set the HAPI ports to transmit and receive Unicast?
5. What testing has your team done, how was it set up?

HAPI Unicast --> ISP --> Internet --> Cloud (No Multicast allowed) --> Internet --> ISP --> HAPI

tiborknowles
Posts: 23
Joined: Sun Oct 26, 2014 04:41

Re: HAPI over WAN and Unicast

Postby tiborknowles » Tue Mar 19, 2019 18:37

6. What happens if location A loses GPS lock. Will the signal be un-decodable at location B? And visa versa.

tonzauber
Posts: 12
Joined: Sun Feb 18, 2018 12:10

Re: HAPI over WAN and Unicast

Postby tonzauber » Wed Mar 20, 2019 14:27

GPS has proven to be not precise enough to clock multiple distant locations (e.g. OB-VAn and Broadcasting center) from different GPS Clocks on their relative locations, as the time base changes by altitude. Compensating this in theory is possible, however was never succesfully implemented (as far as I know)
Therefore it has always been method of choice de-synchronize different locations, by framestores and/or SRC.

With Audio-Over-IP, the PTP has the advantage of implementing in itself a hierarchic clocking structure for easy switchover in case an incoming clock signal becomes unreliable. However for the whole audio network only ONE PTP grand master is allowed at a time.

So far I don't know of any audio-over-ip solution that would allow to connect different clock domains directly in the same network without going via an intermediary format.

tiborknowles
Posts: 23
Joined: Sun Oct 26, 2014 04:41

Re: HAPI over WAN and Unicast

Postby tiborknowles » Fri Mar 22, 2019 01:22

I see what you're saying about GPS time base changing with altitude. So the two clocks will never be in perfect sync. As they say, a person with two wrist watches never knows what time it is :)

So you run the risk that if clock B is faster than A, then B will try and play packets that are not ready to present yet? I wonder if at 48khz you could get away with that.

Merging folks, any thoughts on this? I have read in the HAPI notes somewhere that some unicast provisions have been made for internet streaming. Please expound.

Thanks, Tibor

tiborknowles
Posts: 23
Joined: Sun Oct 26, 2014 04:41

Re: HAPI over WAN and Unicast

Postby tiborknowles » Mon May 13, 2019 23:37

FYI- I discovered that its common practice for clock manufacturers to compensate for the prop delay of the Satellite transmit and the clock receiver. So you can precisely sync multiple distant locations.