Author Topic: Cmd Latency, delay to start.  (Read 4769 times)

VK3OE

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Cmd Latency, delay to start.
« on: 2012-02-19, 07:06:53 »
Hello,

I am using HRD to connect to a remote IC7000. RTP status is excellent (60), UDP cmd status is OK(45) and the audio and CW work very well with RX jitter buffer size = 5, RX jitter delay 3 and packet size of 6ms.

However, when using the tuning via HRD there is always a delay to start (of up to several seconds) and after that the tuning (or any other HRD control) runs very well. If I do not tune for several seconds, then the same happens again with a delay to start.

Using HRD on a IC 756P3 locally at the same baud rate the issue described above is not evident at all so it is not the computer or HRD. If I connect a laptop at the remote site using HRD this issue is not evident at all.

There thus seems to be an issue when there is a higher latency with serial bandwidth allocation although the audio is great with no breaks.

Is it possible that a permanent allocation of bandwidth can be made for the UDP cmd function so that when tuning starts there is no latency while bandwidth is allocated for the cmd/ serial functions. Even if zeros are sent if there is no serial traffic just so that the bandwidth can be permanently held for the serial functions so that tuning using HRD starts instantly please.

Thanks for a great product.

Andrew
VK3OE/VK3OER

sm2o

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Re: Cmd Latency, delay to start.
« Reply #1 on: 2012-02-19, 12:20:15 »
You are not describing what equipment or internet connection you are using. But there is no delay in sending the meesage over the Internet from the RRC, it's done as soon as the end of message character is received.

But with some mobile eg 3G connections we got reports that the beginning of the audiostream was missing or messed up. Those who had problem thougt that it took awile before the mobile network started to send a continuous stream of packets.  We introduced the possibility to send continuous audiostreams in both directions and the problem was solved.

Maybe you have the same situation for the command stream, but it's not that easy to send dummy data packets over the link to keep the bandwidth constant.

73 de mike

dj0qn

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Re: Cmd Latency, delay to start.
« Reply #2 on: 2012-02-19, 13:20:21 »
I am not sure if Andrew has "continuous RTP" turned on, but he should try that
to see if it helps or solves his problem.

73,
Mitch DJ0QN / K7DX

VK3OE

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Re: Cmd Latency, delay to start.
« Reply #3 on: 2012-02-20, 04:22:26 »
Hello Mike and Mitch,

Thanks for your reply and thoughts. The connection is via ADSL at both ends at a speed of 4.9Mbps, and the network latency is about 60ms. The data each way streams at around 300kbit/s, audio is linear 16 bits, 12kHz.

I tried the RTP on that Mitch suggested but that makes the problem worse. With RTP off, as long as I move the cursor the radio keeps tuning. If I pause the cursor tuning, then start again it takes some time to start tuning again.

I tried full duplex as Mike suggested and that does seem to reduce the delay to start. The function buttons in HRD also react more quickly so the problem is much reduced, many thanks.

Andrew,

VK3OE/VK3OER