[OZAPRS] HF Gateways

James Cameron VK2LQZ vk2lqz at wia.org.au
Mon Jun 29 18:20:01 EST 2009

On Mon, Jun 29, 2009 at 06:06:32PM +1000, Ray Wells wrote:
> With numbered ax25 frames the "within reason" is determined by RETRY  
> which is typically 10. Is the TCP/IP equivalent the TTL (Time To Live)  
> parameter?

No.  TTL determines how many times a single packet is repeated by
internet routers and gateways before it is no longer repeated.

The amount of time a TCP connection may be stalled doing retries is
determined by (a) any keep-alive setting of the operating system or
application, or (b) any timer in the application that eventually gives
up and announces a timeout.

TCP retries use an exponential backoff.  I'm not yet sure what AX.25
uses.  Still learning AX.25.

APRS uses "if it didn't get through, don't worry, we'll send another one
soon."  ;-)

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