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<p class="MsoNormal" style="margin-bottom:12.0pt"><span
style="font-family:"Verdana",sans-serif">Interesting...
If one can take the report at face value they mention
that the 911 centers could see the phone number of the
caller and then was able to call them back. Assuming
this is a VoIP system, honestly what phone system
isn't these days, this tells me that the SIP traffic
was making it through but the audio data was not.
These are typically carried on different network ports
and require specific firewall rules to allow them
through. There is a common problem with VoIP system
refereed to as 'one-way audio' in which the calls are
connected but only one of the parties can hear the
other. This situation is almost always caused by a
misconfiguration of a firewall. It could also have
been a defense mechanism whereby some firewalls can
block specific ports if it sees 'unusual' activity on
a port.<br>
<br>
If this was the case no amount of redundancy/failover
would have helped - the system wasn't down, calls were
still going through.</span><br>
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<br>
FWIW, I was a principal software engineer at Oracle for 15 3/4
years. If your business is airline reservations or online sales
(amazon) or yes, 911 centers etc, you can't lose a single
transaction.... ever. Your computers can crash or one of your data
centers can literally burn to the ground and you just keep going. We
know how to do this.<br>
<br>
73s, Tony, W1DYS<br>
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