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<section xml:id="introNetworks" 
         xmlns="http://docbook.org/ns/docbook" 
         xmlns:xlink="http://www.w3.org/1999/xlink" 
         xmlns:xi="http://www.w3.org/2001/XInclude">

<info>
  <title>DMR Networks</title>
</info>

<para>
  Within the previous sections, I tried to outline the concepts and some technical details of a 
  DMR network and how a codeplug might be assembled. These concepts, however, apply only to the
  so-called <glossterm>Brandmeister</glossterm> network. This is the network in the background that
  routes your private and group calls, connects repeaters etc. In Germany, this is the dominant 
  network. But also world wide, it connects the majority of repeaters (about 5000). However, there
  are also other networks. There is the <glossterm>DMR-MARC</glossterm> network and the 
  <glossterm>DMR+</glossterm> network. Which network you are likely to encounter, depends on your 
  location. In countries like France, Spain, BeNeLux, Poland, Czech Republic and Slovakia, almost
  all repeaters are connected to the Brandmeister network, while in Denmark the DMR+ network 
  dominates. In the USA and Austria, DMR-MARC repeaters aren't rare. All these networks do not 
  differ on the technical level. That is, you DMR-ID is valid in all of these networks and you 
  can use any DMR Tier II radio.
</para>

<para>
  The concepts however, in particular how group calls are performed, depends heavily on the 
  network. This means, that you need to configure the repeater channels for a DMR+ repeater
  in a different way compared to a Brandmeister repeater.
</para>

<section xml:id="itroReflector">
<info><title>Reflectors (DMR+)</title></info>

<para>
  <glossterm>Reflector</glossterm>s play an important role in the DMR+ network. They represent
  a talk group within the DMR+ network.
</para>

<para>
  The major difference between a reflector and a talk group is, that they cannot be simply called
  using a group call. They are subscribed to a local repeater by a private call to the 
  reflector. Then all repeaters subscribed to that reflector behave like a single repeater. You will
  then participate on that reflector by performing a group call to TG9, the local talk group. Your
  call will then be sent to the reflector as well as to all other reflectors currently subscribed 
  on the repeater and consequently to all repeaters also subscribed to that reflector.
</para>

<para>
  This has the advantage of a much simpler codeplug assembly, as only two channels are configured 
  for each repeater. One for each time slot. The default transmit contact will always be the 
  local talk group TG9. To subscribe a reflector, a private call is started to the reflector from
  the contact list. This implies that the contact list should contain all reflectors you are 
  interested in. This concept is also much closer to the semi-analog concepts of EchoLink. However,
  advanced features like roaming are not possible this way. Also the repeater transparency gets 
  lost. Instead of simply starting a group call to the destination talk group, the local repeater 
  needs to be <quote>configured</quote>. Once that configuration is done, the communication will
  happen on the local talk group TG9, even if the communication is not local anymore. 
</para>
</section>

</section>