Thursday, June 16, 2011

IP Telephony Implementation at Villa Maria National University

Villa Maria National University is an education organization established at Villa Maria city in Cordoba State, Argentina. Two years ago directives of the university order the transfer of the existing telephony network to an IP platform, with a preliminary evaluation of technical and economical feasibility.

Universidad Nacional de Villa María

Argentina

Mariano Martín

Villa Maria National University is an education organization established at Villa Maria city in Cordoba State, Argentina. Two years ago directives of the university order the transfer of the existing telephony network to an IP platform, with a preliminary evaluation of technical and economical feasibility.

Different versions of Asterisk were analized in several Linux distributions at virtual environments. At the end the solution chosen was an integral/complete distribution.

The initial tests were performed on Elastix v1.2 32 bits in a real server using Digium clone cards (modems with Motorola/Intel chipset) with FXO ports connected to the PSTN. At this stage Softphones and IP phones were use for users.

Once the tests concluded, the authorities of the University took the decision of change the platform in their policies.

A Network adjustment was made in order to work with VoIP, also a there was a replacement of some switches by others with Power over Ethernet.

The infrastructure of the main Communication server was installed in an Intel Xeon/ HD 500 GB server with Elastix v1.3 32 bits.

At first we install 10 extensions using Grandstream IP Phones model GXP2000.  We also used a Sangoma A200 card with 4 FXO ports to access the PSTN.  This implementation was executed at one of the extensions of the University Campus.

In the next stage we include a Sangoma A200 telephony card with echo cancelation to expand the telephony integration to a total of 24 FXO ports. With this expansion we create more users to the system that include 100 extensions at the Dean Headquarter using different IP phone models (GXP2000, GXP1200, GXP280, and BT200). We also added console operators for more than 100 BLF indicators.

In addition to the 100 users, 10 Grandstream GXV3000 IP VIDEO phone where included. For this purpose, we enabled video support and all necessary codecs.

In the following stages the University incorporated a new Elastix v1.3 de 32bits server with the same hardware characteristics. for the Central Campus The telephone integration was made with a Sangoma A200 card with 24 FXO ports.  Both servers were interconnected with IAX2 Trunks and a dedicated wireless link with 22Mbps and 100 extensions where added.

The main goal of having two servers with their own access to the PSTN is to avoid the lack of communication between the extensions if the link failed at some point.

For this functionality we create 15 users and used telephone adapter switches (ATA) for Fax machines.  After that we created 20 virtual FAX (Hylafax), all of them redirected to several emails. There is also an access to FAX from the PC with Winprint Hylafax.

Some of the following features where enabled:

A freepbx CUSTOM-CONTEXT module was installed to manage different access to the PSTN for internal groups.

Conference Call, Call transfer, Call Pick-up, Call forwarding, Ringing groups, IVR, etc…

A call billing feature was enable, this was possible by including a destiny code to the bill. A2Billing was configured in order to work with different users with a billing process and prepaid call system.

Currently there is a development in AGI-PHP to use a text to speech application to allow teachers and students to make consultations of a database. This prototype is already working.

This implementation is part of a project that includes a complete implementation of IP telephony and Unified communications at the Villa Maria University which include a lot of work and further conclusions.

Some load data where obtained by creating modifications in the PHP code of the following module to reports and graphics in Elastix:

/admin/common/graph_hourdetail.php

This made possible to obtain the MAX LOAD value of the server in concurrent calls.  We modified the code to obtain that value in a regular day and then for a complete month.  We got the following results:
Dean Headquarter IP-PBX Server

Dean Headquarter IP-PBX Server


Here you can appreciate that January is the month with the lowest activity due to the summer vacations and the higher activity was detected on December 2009 with 21 concurrent calls registered in the Principal server and 14 concurrent calls registered in the  Campus server.

Elastix allowed us to reduce the implementation times. It is also useful to the system administration allowing the addition of more users with an easy training thanks to the information available.

At the moment of the publication of this case we have 4 servers interconnected with IAX2 and SIP.

The total number of extensions is 250 and we are working on a main project that will include VoIP platforms of other Argentinean public Universities to our system through a Proxy SIP Server.  

The coordination of the telephony network that includes 18 Nacional Universities is performed at The Villa Maria National University and San Luis.

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