[asterisk-users] ISDN PRIs and taking a server down formaintenance - blocking issue
Brent Davidson
brent at texascountrytitle.com
Thu Feb 14 18:29:32 CST 2008
Correct me if I'm wrong, but as I understand it your issue is that when
you give Asterisk the "stop gracefully" command it waits until all
active calls have finished before it takes the ISDN down but gives busy
signals to new incoming calls on idle channels. If this is the case
then it would seem that Asterisk is actually answering the call on the
incoming channel and playing a busy signal. From reading a couple of
threads on another list it appears this is the case (Google: Asterisk
"busy out" PRI to find the discussion). There also appears to be some
interest in making a function do what you need in the future.
For the time being, however, a simple solution would be to create a
temporary dial-plan that follows each outgoing hangup with a "dial"
command to either a test number or some other service that will just
keep playing audio down the line and not hangup. (You'd probably need
to set some variable to know which channels had been "busied") When you
need to take down a server, load this dial plan and wait for all
channels to call the "busy" number, then hang them all up and issue a
"stop now".
It's a messy solution, but it's all I can think of without hacking
code. The only other way I'd know would be to hack the code for the
dial or answer command and build another command that simply takes the
channel off-hook and leaves it there.
Good luck,
Brent Davidson
Lyle Giese wrote:
> If you take Asterisk down, the PRI should go down as the D channel is
> down. Then the telco should KNOW that there is trouble with the PRI
> and those channels are in trouble busy and not availible. If the
> telco still tries to push a call to a channel on a PRI that is down,
> then the telco is at fault.
>
> Lyle
>
> Matt wrote:
>> That does sound like what is happening.. Telco knows channel 1-23 are
>> not busy (so far as they are concerned), however.. so far as you are
>> concerned, they are busy.. so telco sends the call down... but the
>> equipment doesn't take it.
>>
>> I would *think* the Telco could keep trying channels down the hunt
>> group, but maybe not? We have, in the past, seen this issue with our
>> dial-up modem banks.. especially if I would take one offline.
>> However, it is not a big enough issue (i.e. we don't take things down
>> that often) for me to look into it fully.
>>
>> On Thu, Feb 14, 2008 at 4:07 PM, Don Kelly <dk at donkelly.biz
>> <mailto:dk at donkelly.biz>> wrote:
>>
>> I think the problem is that the telco presents the call on a
>> specific channel, then zaptel tells it that the channel is busy.
>>
>>
>>
>> We need to be able to tell the telco that each unused channel on
>> a given span is unavailable, and it will determine that the
>> others are in use and will present the call on a channel on
>> another span.
>>
>>
>>
>> A rather ugly work-around (since Andrew seems to have lots of
>> channels available, and one would assume that maintenance of this
>> nature would occur during slow periods) would be to make calls to
>> a DID in the same trunk group on all "idle" channels on the span
>> shutting down then, when all channels on the span are "in use"
>> and none of them are doing anything useful, take the span down
>> hard so the telco will divert all calls to another span.
>>
>> --Don
>>
>> Don Kelly
>> PCF Corp
>> Real Support for your Virtual Office TM
>> 651 842-1000
>> 888 Don Kell(y)
>> 651 842-1001 fax
>>
>> ------------------------------------------------------------------------
>>
>> *From:* asterisk-users-bounces at lists.digium.com
>> <mailto:asterisk-users-bounces at lists.digium.com>
>> [mailto:asterisk-users-bounces at lists.digium.com
>> <mailto:asterisk-users-bounces at lists.digium.com>] *On Behalf Of *Matt
>> *Sent:* Thursday, February 14, 2008 2:28 PM
>>
>> *To:* Asterisk Users Mailing List - Non-Commercial Discussion
>> *Subject:* Re: [asterisk-users] ISDN PRIs and taking a server
>> down formaintenance - blocking issue
>>
>>
>>
>> Honestly.. this sounds like a telco issue. I understand what
>> the other person is saying about the PRI still being technically
>> up... BUT... if the channel is BUSY/BLOCKED/WHATEVER, the Telco
>> should be forwarding the call to the next available channel,
>> which they clearly are not doing.
>>
>> On Thu, Feb 14, 2008 at 8:29 AM, Andrew Smith
>> <andrews at meadeplc.com <mailto:andrews at meadeplc.com>> wrote:
>>
>> Hi Tim,
>>
>> Imagine the scenario where we had 10x Asterisk servers, with
>> calls presenting sequentially starting from the first server,
>> then server two, etc.
>>
>>
>>
>> If we took down the first server for maintenance with 'asterisk
>> -rx stop gracefully' we then will block all incoming calls to all
>> servers as our telco will simply relay the BUSY back to the
>> caller. If there are a number of calls on the first server that
>> continue for another 20 minutes, then all inbounds are blocked
>> for that period of time.
>>
>>
>>
>> We are finding at present we have to look at the calls on the
>> server and make a decision if we are busy to simply reboot the
>> server and hence lose calls. Not ideal but then we don't end up
>> blocking our inbounds.
>>
>> What I was hoping to do was find a way to cause the telco to
>> present the call to the next ISDN30 and therefore would allow us
>> to cleanly take down an Asterisk server for maintenance without
>> causing this issue. In a sense to put the ISDN30 into alarm mode
>> while still continuing the active calls.
>>
>>
>>
>> Do you know if this is at all possible, even if we considered
>> patching zaptel to add this functionality or does the telco rely
>> on the entire PRI being in alarm before it presents the call to
>> the next ISDN30 ? This would allow us to run maintenance on our
>> servers during busy periods without causing disruption, and would
>> be an excellent feature.
>>
>> Many thanks,
>>
>> Andrew
>>
>>
>>
>> ------------------------------------------------------------------------
>>
>> *From:* asterisk-users-bounces at lists.digium.com
>> <mailto:asterisk-users-bounces at lists.digium.com>
>> [mailto:asterisk-users-bounces at lists.digium.com
>> <mailto:asterisk-users-bounces at lists.digium.com>] *On Behalf Of
>> *Tim Nelson
>> *Sent:* 13 February 2008 18:12
>> *To:* Asterisk Users Mailing List - Non-Commercial Discussion
>> *Cc:* asterisk-users at lists.digium.com
>> <mailto:asterisk-users at lists.digium.com>
>> *Subject:* Re: [asterisk-users] ISDN PRIs and taking a server
>> down for maintenance - blocking issue
>>
>> Even if * is shutdown, zaptel is still running and your ISDN
>> channels are still technically up. Shutting down zaptel should
>> close the channels and put those circuits into alarm mode.
>>
>> Tim Nelson
>> Systems/Network Support
>> Rockbochs Inc.
>> (218)727-4332
>>
>> ----- Original Message -----
>> From: "Andrew Smith" <andrews at meadeplc.com
>> <mailto:andrews at meadeplc.com>>
>> To: asterisk-users at lists.digium.com
>> <mailto:asterisk-users at lists.digium.com>
>> Sent: Wednesday, February 13, 2008 12:03:51 PM (GMT-0600)
>> America/Chicago
>> Subject: [asterisk-users] ISDN PRIs and taking a server down for
>> maintenance - blocking issue
>>
>> Hi there,
>>
>>
>>
>> I currently have multiple Asterisk servers using Sangoma A104d
>> Quad ISDN E1s.
>>
>>
>> Basically our telco is presenting calls in order of the ISDNs on
>> our servers.
>>
>>
>>
>> SERVER1=1,2,3,4
>> SERVER2=5,6,7,8
>>
>>
>>
>> We have redundancy in that if SERVER1 is shutdown then each ISDN
>> PRI is in alarm and the calls will then presented to PRIs 5,6,7,8
>> on SERVER2.
>>
>> If I have to take SERVER1 offline for maintenance (asterisk -rx
>> shutdown gracefully) any incoming calls receive a BUSY tone.
>>
>> What I would like to know is if there is anyway to get around
>> this and not send a BUSY back to our callers and somehow allow
>> our telco to present calls immediately to SERVER2.
>>
>> Anyone have any ideas or are we stuck with this behaviour until
>> the calls drop to 0 and Asterisk shuts down ?
>>
>> Thanks,
>> Andrew
>>
>>
>>
>>
>>
>>
>> _______________________________________________
>> -- Bandwidth and Colocation Provided by http://www.api-digital.com --
>>
>> asterisk-users mailing list
>> To UNSUBSCRIBE or update options visit:
>> http://lists.digium.com/mailman/listinfo/asterisk-users
>>
>>
>>
>>
>> _______________________________________________
>> -- Bandwidth and Colocation Provided by http://www.api-digital.com --
>>
>> asterisk-users mailing list
>> To UNSUBSCRIBE or update options visit:
>> http://lists.digium.com/mailman/listinfo/asterisk-users
>>
>>
>> ------------------------------------------------------------------------
>>
>> _______________________________________________
>> -- Bandwidth and Colocation Provided by http://www.api-digital.com --
>>
>> asterisk-users mailing list
>> To UNSUBSCRIBE or update options visit:
>> http://lists.digium.com/mailman/listinfo/asterisk-users
>
> ------------------------------------------------------------------------
>
> _______________________________________________
> -- Bandwidth and Colocation Provided by http://www.api-digital.com --
>
> asterisk-users mailing list
> To UNSUBSCRIBE or update options visit:
> http://lists.digium.com/mailman/listinfo/asterisk-users
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.digium.com/pipermail/asterisk-users/attachments/20080214/039f8ef3/attachment.htm
More information about the asterisk-users
mailing list