AEQ
PHOENIX STRATOS
60
•
Local media port: this option allows you to configure the value of the IP port
selected to transmit audio at origin over IP. Minimum value 1,024. Maximum value
65,534. Usually recommended value 5004.
•
Adaptive/Fixed and Adaptive buffer max/Fixed buffer length: this option allows
you to configure the type and maximum size of reception buffer. See section 3.4.
•
Symmetric RTP: when “SmartRTP“ mode is not activated, this advanced option at
least allows the user to force the local unit to send audio to the same IP and port
from which it is receiving audio. The destination port specified when making the call
will be ignored when we receive packets from the remote equipment. This option
will allow you to connect to an audiocodec with unknown IP and/or port (because
it’s behind a router with NAT, for instance).
Please notice that “RTP Point to Point” is a complex configuration mode, suitable for permanent
connections that some equipment may not support. Specifically, it can’t be used to connect to
Phoenix Mobile. However, it becomes an easy and effective way to operate with the aid of
“SmartRTP“.
4.2.3.1. Sending audio to multiple destinations: Broadcast, Multicast and Multiple
Unicast.
It is possible to send the same audio RTP stream to several different destinations in “RTP raw”
mode. There are several possibilities to do so (see “AEQ ControlPHOENIX” manual):
a) Broadcast: the audio stream can be sent to all the equipments within a local network, only
by specifying a special address in the destination address field. This address is calculated as
the network address with the equipment part filled with 1’s. For instance: if the IP address of our
codec is 192.168.20.3 and network mask is 255.255.255.0, the corresponding broadcast
address is 192.168.20.255. However, if the network mask was, for example, 255.255.0.0, then
the broadcast address would be 192.168.255.255. The audio will be sent to a given port, so the
receiving equipments should have “local media port” set up to this same port so they are able to
receive the RTP stream.
This mode is not recommended for big networks and is usually blocked by the switches and
routers, so its use is restricted to small, well managed local area networks.
b) Multicast: it is also possible to send the audio stream to a special “multicast” address, for
example, 239.255.20.8. If the receiving equipments call to that same IP, they will receive the
audio that is being sent provided that their “local media port” matches the one the transmitter is
sending the packets to. Similarly to broadcast, multicast traffic is usually blocked by switches
and routers, so its use is restricted to local area networks too.
c) Multiple-unicast: Phoenix units can send the same RTP stream to several different IPs by
replication of the encoded audio. This can traverse switches and routers in the same way it
would do if it was a simple (unicast) RTP Raw stream, although it is limited to a certain number
of destination IPs depending on the type of coding algorithm.
The “Multiple unicast” button (within the IP interface configuration screen Net1 or Net2) gives
access to an information window where the replicas that are active at a certain moment are
shown.
