asterisk users - Jul 2003 - Switch issues with non-dedicated comms.. (My experience)

Hi,

NOTE: This mail is sent for general information based on my experience to the
Asterisk community not as an attack on Asterisk which I think is an amazing
system..

Some of you may have seen my posting a few days ago where I was having problems
with using the "switch" command in my dialplan..

It was suggested to put the switch command into its own [context] and then to
include it into the contexts where it was required.. While using switch in the
context that contains all my extensions or using it in a seperate context and
then including it both worked fine on my setup this had not solved the issue I
was having. After more testing I would simply advise that anyone who does not
have a dedicated (and somewhat reliable) link between their two systems simply
don't use the switch command and rather configure a wildcard extension
mapping to the remote Asterisk system..

The problems I experienced is that when the link between the two servers is down
the local server becomes highly unreliable..

Firstly when dialing an outside line it attempts to search the remote (at this
time unavailable) dialplan before it has processed all the local options, This
causes a massive delay between the time the call is dialed and the time the call
actually starts the connection.. I have tried qualify=yes in the iax.conf but
this did not alter the call processing routine in any way or reduce the time it
takes from the time the number is dailed to the time it finds the extention
mapping it needs to use..

The second issue is that when the line is down and an outbound call is placed
(on my local system it is using an X100P) the call will terminate after approx
1-2 mins for no apparent reason.. I can only assume this has somthing to do with
Asterisk trying to test connectivity with the remote system or somthing else to
do with the switch command becasue when I comment out the switch command and use
wildcard extension mappings the problem is gone..

so effectively what I have done is replaced this..
switch => IAX2/...

with this..
exten => _2xxx,1,IAX2/...
etc..

Now I am sure many of you are going to respond and tell me that my dialplan is
wrong or that you are using switch and its perfect.. Thats all fine and I agree
that switch is perfect when the link between the two systems is up.. All I am
saying is that one day when you link is down for whatever reason and suddenly
your local pbx starts to freak out and has long delay when placing a call or
disconnects you constantly then rememebr my experience.. It will save you many
hours of stress..

Later..


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> The problems I experienced is that when the link between the two
> servers is down the local server becomes highly unreliable..
>
> Firstly when dialing an outside line it attempts to search the
> remote (at this time unavailable) dialplan before it has
> processed all the local options, This causes a massive delay
> between the time the call is dialed and the time the call
> actually starts the connection.. I have tried qualify=yes in the
> iax.conf but this did not alter the call processing routine in
> any way or reduce the time it takes from the time the number is
> dailed to the time it finds the extention mapping it needs to use..
Perhaps something similar to the qualify for SIP clients could be
implemented with IAX and IAX2 connections, ie, if ping time is greater than
qualify time, then don't use it.

It would also help if periodically asterisk would collect the extensions
list for each switch statement included. This might cause minor problems if
your extensions change frequantly (perhaps rather than just a periodic check
include support to 'notify' remote servers when the local dialplan is
changed like the BIND DNS support for zone files).

I have only just started using IAX connections over a 64k ISDN link, and it
is bearable as long as there is no other traffic using the link at the same
time... I am yet to really play with it and make it work fantastically.


Regards,
Adam