System information

systems to live on low-latency links, which typically means they all need to reside in
the same physical location, attached to the same switch. That said, while the OpenAIS
library does not work across physically separate networks, it does allow a Queue() to
reside on one system and queue members to reside on another system (or multiple
systems). It does this without requiring us to use Local channels and test their availa-
bility through other methods, thereby limiting (or eliminating) the number of connec-
tion attempts made across the network, and multiple device ringing.
Using OpenAIS has an advantage, in that it is relatively easy to configure and get work-
ing. The disadvantage is that it is not distributable over physical locations. As of Asterisk
1.8, though, we can use XMPP for device state distribution over a wide area network,
as you’ll see in the next section.
More information about configuring distributed device states with OpenAIS is available
in “Using OpenAIS” on page 310.
Distributing Device States over a WAN
As of Asterisk 1.8, an implementation that uses XMPP for device state distribution has
been added. Because the XMPP protocol is designed for (or at least allows) usage across
Figure 22-6. Device state distribution with OpenAIS
Asterisk and Distributed Device States | 497