Wheatstone Corporation WheatNet-IP BLADE3, Техническое руководство

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WheatNet-IP BLADE 3 / June 2018
page A – 116
A P P E N D I C E S
Multicast Address Range
Streams that are intended to be sent to more than one device take advantage of a standard
IP mechanism, multicasting, to maximize network efficiency. In this protocol every stream
is given a unique multicast address to identify it on the network so standard switches can
send its packets to the devices that want them, but not to devices that don’t want them.
The number of available multicast addresses is very large and individual device
manufacturers could chose any of these multicast addresses to use in their system. AES67
specifies a particular range of addresses that must be used in order to assure potential
compatibility.
Ports
Ports provide a mechanism in IP networks of pre‑identifying the type of information
that will be contained in the payload of a packet. For instance an smtp email message will
be directed to port 25 so the receiving device automatically knows to forward the payload
data to the email application without having to decode the actual payload to figure out
what it contains.
AoIP is similar in that it is desirable to forward the payload data directly to the AoIP
streaming application. Of course different vendors have chosen their own ports to use:
AES67 specifies a standard port, 5004, that all devices should be capable of using.
Conclusion:
By providing specific configuration details for AoIP streams, AES67
makes it possible for devices that adhere to these details to stream audio between them.
Since vendors of AoIP devices may have existing systems that were built before there
was an AES67 standard and will want to maintain streaming capability with their own
equipment, there must be a mechanism to specify these details on a case by case basis as
the needs arise. In WNIP this is done via the Navigator software application. Other AoIP
vendors have their own mechanisms to use to alter their device configuration parameters
and you’ll need to be familiar with and use each venders methods for the AES67 devices
you’ll have in your system.