[OZAPRS] HF Gateways

James Cameron VK2LQZ vk2lqz at wia.org.au
Mon Jun 29 18:14:05 EST 2009

On Mon, Jun 29, 2009 at 05:48:02PM +1000, Jamie Campbell - VK2YCJ wrote:
> I suspect that Echolink doesn't use a standard VOIP UDP protocol because 
> I have NEVER heard a crook Echolink transmission.

http://www.echolink.org/firewall_solutions.htm shows that EchoLink (R)
does indeed use UDP as well as TCP.

You are correct though in that TCP acknowledgements double the air time
cost of data transfer as compared to unacknowledged UDP.

It is quite rare to lose UDP packets regularly ... but software that
uses UDP is meant to assume that loss may happen.  Whereas software that
uses TCP is given a guarantee by the protocol that loss will not happen,
that the protocol will cause a retransmit instead.  If the retransmit
is unsuccessful, the software will never get what it wanted.

James Cameron    mailto:quozl at us.netrek.org     http://quozl.netrek.org/
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