Last Updated: 14-March-2013

If you are about to dive into the process of virtualizing some of your Asterisk infrastructure then some primary issues might be preventing you from moving (e.g. the lack of proper timing as you need it for IAX2 trunking). If this is your case, consider these options and the pro and cons of each one:

• OpenVZ - Better resource usage, lower overhead. Primary issue is how to grant access to host node timing source (physical device, or dahdi_dummy in /dev/dahdi/) to the containerized Asterisk process.
• KVM - Higher overhead, easier installation, ‘true virtualization’. Primary issue is not timing per se, but KVM scheduling. Timing source, while present from dahdi_dummy natively may still not get proper scheduling by KVM process. This could also affect general call quality (even non IAX2 trunked voice), DTMF, etc.
• VMware – They are moving all server products to their ESXi engine. (The old VMware “server” and ESX products are moving to legacy status – with these you could actually do stuff on the kernel). ESXi is no longer a kernel you can mess with, can’t install drivers, etc. ESXi is being treated as an appliance that you cannot and should not touch (even authorized partners like HP only get to add software through VMware). Many of these devices are not (and will not be) recognized by the VMware kernel, so forgot about host support. At best you can pass-through the device to a single guest, but then you lose the whole point of a shared timing source.
• XEN - Virtual machines can use both hardware- or paravirtualization. It has been used to separate machines where people should do their sip-registration (internet / intranet /
  pstn-gateway) and the actual dial-beast.

In order to take the most out of virtualization besides easy scaling and ability to perform an upgrade in no-time, upgrade to the latest version of Asterisk, as it has a newer timing source that don’t rely on Dahdi and a complete rewrite of ConfBridge which doesn’t require Dahdi for mixing at all.

Phone records lookup is a policy you might want to apply in your company in order to get sure that your resources are being used in a proper way, by analyzing where the calls being made. Or maybe the scenario is that you have developed an application for Asterisk to accept creditcards using a payment gateway and you need to look for a reverse phone lookup services in order to get the full address of the caller (not just state,city).

Whatever the reason you might have to use this kind of services, here we provide some options that you should consider some provider that might even provide APIs, so the integration of forms might be possible.

Recently The Asterisk Development Team announced the release of Asterisk versions 11.0.2, 10.10.1 and 1.8.18.1 and made them available for immediate download at:

• http://downloads.asterisk.org/pub/telephony/asterisk

All of the releases resolves one or more issues reported by the community, without whose participation it wouldn’t have been possible.

The following is the issue resolved in this release:

•  chan_local: Fix local_pvt ref leak in local_devicestate(). (Closes issue ASTERISK-20769. Reported by rmudgett)

Please read the change logs for a full list of changes. Thank you for your continued support of Asterisk!

As its name implies, a telecommunication system is first a communication system, that is, a system to transmit information from one location to another. And secondly, a system that allows you to transmit information from locations with a considerable distance between them. That’s what the prefix tele means in greek = distant.

As in any communication system, it’s composed by 3 parts:

• The transmitter
• The channel
• The receiver

and it can be analog and digital.

Basically, a communication system is composed by three parts: The transmitter is the first component. That’s the part of the communication system that sits at point A. It includes two items: the source of the information, and the technology that sends the information out over the channel. The second component is the channel. The channel is the medium (the conduct) that the information travels through in going from point A to point B. An example of a channel is optical fiber, or the air. Finally, there’s the receiver, the part of the communication system that sits at point B and gets all the information that the transmitter sends over the channel.

An example of communication system would be a conversation between you and one friend. The transmitter would be the person talking (and the two items would be the vocal cords and the windpipe). The channel in this example would be the air between persons speaking, and the Receiver would be the other person that is listening while the first one speaks.