A Closer Look At Cobranet; Fast Ethernet - Crown CTS4200 Operation Manual

8 Network and CobraNet Basics
Each component has three identifi ers that are used in the HiQnet
system:
• Media Access Control (MAC) Address
• Internet Protocol (IP) Address
• HiQnet Address
Let's explain each identifi er.
Media Access Control (MAC) Address: This is a physical
address that specifi es a specifi c physical network component.
This address is predefi ned during manufacture and cannot be
modifi ed. No two network components have the same MAC
address and each component is uniquely identifi ed by its MAC
address. This 48 bit address is located on the outside of every
HiQnet component and is shown in hexadecimal format as 6 two-
byte octets such as:
00-0A-40-00-DC-2F
Internet Protocol (IP) Address: The IP address of a
compo nent is assigned during the setup of the network and
identifi es the IQ component to a larger audience. Because the
MAC address is limited to a single physical LAN,
communications between LANs is impossible solely through the
use of the MAC address. The IP address allows components and
controllers on other networks to communicate with each other
through the use of an IP Router as shown in Figure 8.2.
Figure 8.3 A Star Network
page 34
(continued)
This allows the network designer to isolate network traffi c from each
other. For example, when using wireless devices to control HiQnet
components, the bandwidth limitation of wireless devices will not allow
them to reside on the same network with CobraNet. As a result, the use
of an IP router and a separate network allows the wireless con trollers to
access the IQ components through the router using IP addressing. The
IP address appears as four numbers (0-255) sepa rated by periods,
such as:
HiQnet Address: HiQnet or TCP/IQ components will be addressed
with a unique number from 1 to 64,000 and are assigned within the
software. The Subnet Mask is four numbers (0-255) separated by
peri ods. For example, a subnet mask of 255.255.25.0 and an IP
address of 192.168.0.127 says that all IP addresses in that LAN are in
the IP address range of 192.168.01 to 192.168.0.255.
If a controller is on a different network than the audio components,
communications must occur through an IP router. discovery requires
the use of broadcast Ethernet data packets onto the network. These
broadcast commands cannot be done through an IP router, therefore a
Discovery Proxy is required. The establishment of this proxy is done in
by naming the IP address of a known component on the component
network as the Discovery Proxy. In System Architect it is done in Tools
> Options > Network Settings > Manage Network Connections.
Figure 8.4 A Multiple Star Network
192.168.0.1
CTs Multi-Channel Power Amplifi ers

8.2 A Closer Look at CobraNet

Licensed by Cirrus Logic, CobraNet is a protocol, fi rmware and
hard ware that lets you transmit digital audio over a 100Base-T Fast-
Ether net network.
This section provides an overview of CobraNet. Peak Audio has
pro vided a number of technical papers that describe CobraNet in detail.
These papers are available at www.cobranet.info.

8.2.1 Fast Ethernet

(100Base-T)
Fast Ethernet (100Base-T) runs at 100Mbps (Megabits per second). It
uses a hub or network switch to interconnect all network nodes
(com ponents). This forms a star network (see Figure 8.3). In a star
network, all PCs are connected to a centralized hub or switch.
Messages are sent from the originating PC to the hub, which then
transmits the mes sage either to the whole network or, if a switched hub
(network switch) is used, to the destination device only.
In larger Fast Ethernet networks, additional hubs, concentrators, and
other network hardware are used to form a larger network, as shown in
Figure 8.4.
Today, commonly available networking cards are 10/100Base-T
capa ble, which allows them to be used on either 10BaseT or 100Base-T
networks.
The maximum length of cable for CobraNet is the same as for Ethernet:
100 meters over CAT-5 copper cable, 2 kilometers over multimode
fi ber. Proprietary "Fast Ethernet via single mode fi ber" networks can
reach even further.
Operation Manual