QSC Audio S series Network Design Considerations:

When a switch is shared with non-CobraNet data, it

should be configured so that CobraNet audio is isolated

from conventional data communications. Partitioning is

usually accomplished by enabling multiple VLANs. Co-

braNet data should be given the highest network prior-

ity in order to prevent the loss of audio. LAN, node, port

and data or packet type prioritization can be defined

through switch management software, industry proto-

cols - such as Request For Comments (RFCs) supporting

Quality of Service (QoS) - and through network design.

Information on VLANs, QoS and network protocol sup-

port is available on the Peak Audio website and from a

host of switch manufacturers.

•Try to assign unicast bundles between RAVE devices

when operating on network switches. This provides

point-to-point communications, which conserves band-

width and prevents port flooding. As a rule of thumb,

CobraNet supports up to four multicast bundles per

broadcast domain or LAN. Audio delivery may be unreli-

able beyond this limit. If the benefit of switches is needed

and the requirement exists for multiple receivers for a

given bundle, it may be necessary to partition the net-

work into smaller LANs. This results in multiple inde-

pendent CobraNet networks on the same switch hard-

ware, each LAN with its own “conductor”. Each LAN can

then support up to four multicast bundles.

Conductor priority may also be a concern on network

switches when implementing multicast traffic. The RAVE

160s-24 and 80s are currently assigned the highest “con-

ductor” priority. Since these units have the least amount

of transmission requirement, they are the best candidates

for handling the “conductor” role. A transmitter with two

outgoing bundles, such as the RAVE 161s-24, may be

overly burdened if it is required to act as “conductor”,

transmit both its bundles, receive unintended multicast

Network Design Considerations: Switched Networks (continued)

bundles and possibly service SNMP messages. The de-

vice defaults should handle these conditions appropri-

ately. However, some configurations may require alter-

ing the “conductor” priority of some devices through the

Management Interface.

•RAVE supports both stand-alone and software configu-

ration. The default mode for RAVE is hardware control.

In this mode, the bundle assignments are set through

the front panel hexadecimal switches. These switches

provide a subset of the available CobraNet bundle as-

signments. These switches also provide access to some

configuration settings such as “external synchronization”,

“software kill”, “serial programming” and selection be-

tween “unicast” and “multicast” addressing. You can

quickly design a RAVE network right out of the box by

simple configuration via the front panel switches.

In software mode, a RAVE is configured through the

management interface using SNMP. With the MI, you

can have access to additional bundle routing, complex

internal audio mapping, audio channel duplication, “con-

ductor” prioritization and more. Generally, a device is

configured via SNMP application software and then the

RAVE is placed into “write” mode so that all settings are

written into permanent memory. The RAVE can then be

moved or power-cycled without the loss of its configura-

tion.

Also in software mode, the front panel switches are used

to provide a unique network name for each RAVE. This

name can be seen in the “sysName” variable within

SNMP. Setting the front panel switches to “FFFF”, and

power-cycling the unit, brings the RAVE out of software

control. This “software kill” feature provides a means to

return a RAVE to stand-alone control in the event a man-

agement console or application software is unavailable.