Peavey MediaMatrix Nion, Hardware Manual

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Chapter 6 - Using XDAB clusters with VLANs and CobraNet
46 Version 1.6.1.0 September 30, 2010
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Introduction
Use of NIONs in an XDAB cluster, particularly when also using CobraNet and VLANs,
creates specific considerations and rules that must be observed in order to insure proper
operation of the system. This chapter is intended to provide awareness of the technical issues
that must be considered when using XDAB clusters and VLANs with CobraNet. A basic
knowledge of CobraNet, NIONs and VLANs is assumed.
Note: XDAB is available on NION n3 and N6 models, but not nX models.
Important concepts
XDAB cluster
NIONs connected together via XDAB are referred to as an XDAB cluster.
There is one XDAB master that provides the audio clock to all other devices in the cluster. The
other devices in the cluster are XDAB slaves.
Audio clock domain
All CobraNet devices on the same network or VLAN segment must operate within the same
audio clock domain. A system wide isochronous audio clock is automatically generated in a
CobraNet network by the standard beat packet mechanism. A NION or CAB will always
receive its audio clock from CobraNet.
Note: An exception exists for NIONs operating within an XDAB cluster:
ƒ In the XDAB master the CobraNet clock can be taken from the CobraNet network as a
CobraNet performer or the XDAB clock can be supplied as the CobraNet Conductor.
Normal CobraNet clocking concepts apply.
ƒ In XDAB slaves the CobraNet clock will always be taken from XDAB and will not be
taken from the CobraNet network audio clock directly. The clock will be taken indirectly
from CobraNet via the clock generated by the XDAB master.
Logical separation of the network
Use of VLANs creates a logical separation of the network that causes the VLAN segments to
behave as if they are physically separate networks. Use of the term VLAN also applies to
physically separate networks.
Each VLAN segment must therefore have its own CobraNet Conductor.
Multiple VLANs
Audio can be exchanged between different VLANs through the use of devices that have a
network interface on each VLAN. This can be accomplished by:
ƒ exchanging analog audio between devices. Devices connected using analog I/O do not
need to be concerned with audio clocking issues between them.
or
ƒ exchanging digital audio between devices. In this case, the audio clocks of the devices
must be synchronous
or the use of sample rate converters on the digital audio inputs is
required.