Hi Azher, > They advertised on TeleVision and then we had a rush of > calls landing on the system (about 30 calls in 1-2 secs and 60 in 3-4 > seconds time).
this sounds like a high number of _simultaneous_ call attempts for a PRI connected system to support. Your comments about a gradual load increase presenting no problem would seem to back this fact up. On most Public Telephone Switches (in the UK) it is advised that no more than 5 call attempts per second should be attempted via PRI if you seek stability. (Above 5 calls attempts per second "Network Congestion" messages can be sometimes be observed on a protocol analyser. These congestion messages can prove fatal for certain applications such as high quality video conferences via hardware that aggregates multiple B channels.) It should be remembered that PRI connections are based upon subscriber signalling specifications and that "spiky" mass call events are traditionally hosted on platforms that are connected via SS7 signalling. I know of similar stability problems with Dialogic and Acculab ISDN connected systems where mass call events, in excess of 5 call attempts per second, have proved too much of a spike for the Public Switch. In certain switch architectures concentrator equipment can also be adversely affected by this kind of deployment which can cause disruption for many customers (not just the one running the PRI IVR platform). On slower CPU systems (< 800 MHz) I have noticed occasional Euro ISDN PRI signalling problems if a high percentage of the 30 channels on an E100P are busy with simultaneous outbound/inbound calls and glare occurs. On the protocol analyser trace it was evident that some messages via the D channel from the Public Switch went unacknowledged by the Asterisk system. If you encounter this problem a quick work around is to split the channels of your single PRI into two trunks to stop the contention between inbound and outbound telephony traffic. (E.g. g1 for incoming and g2 for outgoing calls) I have yet to flex a TE410P with significant traffic levels as all my busy systems are using E100P cards but I have just finished commissioning a TE410P system (with help from Rob Boardman - thanks) in Munich that will be stress tested over the next two weeks; I hope to have news on stability when the tests are completed. HTH Darren -- Comgate (UK) Telco>Internet<Broadcast To: <[EMAIL PROTECTED]> Subject: RE: [Asterisk-Users] PRI issues with TE410P From: "Azher Amin" <[EMAIL PROTECTED]> Date: Thu, 25 Mar 2004 09:09:18 +0500 Hi Tan, I have already turned off the HT from the BIOS (while it was enabled, asterisk was not even stable with 2 pri's). Further I am using the same kernel (2.4.25) with SMP enabled, that u mentioned in your email. Basically I think Scott is right in his emails, that libpri's and zaptel driver for t4xxp are not really optimized and they really need tunings in case when there is certain increase in number of calls .... Also I cannot afford to get a system higher than the current specs. Yesterday I had the same situation, I gave the IVR solution using te410p to a company. They advertised on TeleVision and then we had a rush of calls landing on the system (about 30 calls in 1-2 secs and 60 in 3-4 seconds time). What I have observed is: 1. Asterisk is stable upto 2 PRI's ... no call drops no errors. 2. As soon as I plug in the 3rd pri (3rd pri is confirmed stable), it starts dropping the calls current landing as well as the previous stable landed calls. All calls get dropped and PRIs' start syncing / unsyncing. 3. On the other hand I have also a dialogic server with 4 pri's in it, and it was a rock solid ... going to full 120 calls ... btw: server is just P3 700Mhz, and I have not noticed a single dropped call. 4. My configurations were checked by Mike (@ digium) ... and according to him all things are fine, zaptel,zapata,extensions.conf ... Thus when there is a smooth and gradual load of upto 3 pri's system will remain stable, and when there is an instant call load it becomes shaky. Also I will request those who have successfully done similar setup, to post/advise their linux flavor (and updates), asterisk configurations, kernel configuration, other system tweakings. I want Mark from Digium to take special interest in solving and recommendation on these issues, coz I have confirmed orders of 3 te410p boards and one e100p (for which I mailed to Greg as well), but now I am feeling reluctant to face the client. Regards Azher Amin ------------------------------- http://www.consulttech.com.pk -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Wednesday, March 24, 2004 5:03 PM To: [EMAIL PROTECTED] Subject: RE: [Asterisk-Users] PRI issues with TE410P Before going to gentoo or another version of linux, try the following: 1) turn hyperthreading off in the BIOS. It's probably called something like "virtual cpus". 2) Use a vanilla kernel from kernel.org e.g. 2.4.25. We used to have times when the system would just hang. Using a non-redhat kernel seems to have resolved that. We also use Gentoo, but I warn you that it is not the easiest flavour to set up! Hope that helps. Tan Telappliant.com Voiptalk.org _______________________________________________ Asterisk-Users mailing list [EMAIL PROTECTED] http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
