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Biamp Systems

Separated or converged Control and AVB networks

When creating a system of Tesira devices, it has always been possible to separate the control and AVB media networks. However, in Tesira versions 2.3 and earlier there was one important exception: if Tesira audio expanders were used, it became necessary to connect (converge) the control and AVB media networks into a single network.

Tesira versions 2.4 and later include a new feature that removes this limitation, and allows the AVB and control networks to remain separate even if expanders are used in the system.

The simplest application of the new feature is that a Tesira audio expander can now be connected directly to the AVB network interface of a SERVER , SERVER-IO, or TesiraFORTÉ. This allows a small system to be expanded without the need of an AVB-capable network switch*.

In larger installations, the Tesira system can share the building’s network for control purposes, and a separate, dedicated AVB media network can be installed alongside it. The decision on whether or not to connect the two networks can be made according to user requirements.

*Remote expanders are PoE+ powered, so an inline PoE+ power source is required.

Overview

The key to understanding the new features is a simple distinction between the two types of Tesira audio devices.

The Tesira SERVER, SERVER-IO (AVB) and TesiraFORTÉ (AVB) have two network interface cards (NICs): one for control functions and another for AVB audio. In contrast, Tesira audio expanders (EX-MOD, EX-IN, EX-OUT, EX-IO and EX-AEC) have a single NIC for both control functions and AVB audio.

In Tesira version 2.3 and earlier, a server* would manage an expander via its control NIC, but send and receive audio to the same expander via its AVB NIC. An AVB switch is required to facilitate the connection between the devices.

In Tesira version 2.4 and later, a server* can be configured to do expander management via its AVB NIC. This means a server's* control NIC and AVB NIC no longer need to be connected to the same network to use a Tesira audio expander.

*SERVER, SERVER-IO, or TesiraFORTÉ

Summary

In Tesira version 2.4 or later, the network infrastructure can be configured in one of two ways, regardless of the number and type of devices in the system:

  1. The default setting: to use a converged control and AVB media network
     The system will use a single network, common for both the AVB audio and control functions of the system
     
  2. The optional setting: to use separated control and AVB media networks
    The system will use two unconnected networks: 

i) The control network, for all control functions apart from the management of audio expanders
ii) The AVB media network, for AVB audio transport and the management of expanders*.

Notes:

Converged is the default option for Tesira version 2.4 and later, and it was the only option for Tesira version 2.3 and earlier. This means that a system can be updated from Tesira version 2.3 to 2.4 without reconfiguring the software or the network.

If the Tesira system is configured to use separated networks, the control and AVB media networks must be physically or logically separated. See Essential rules

*Logic expanders (e.g., EX-LOGIC) and remote control devices (e.g., TEC-1 and HD-1) may be placed on either network.

Diagrams

Click on any diagram below to expand it to full size:

Converged network example (default for Tesira 2.4 and later; standard in 2.3 and earlier)

Figure 1 - converged network example (default for Tesira 2.4 and later; standard in 2.3 and earlier)

 

Separated networks example (optional in Tesira 2.4 and later)

Figure 2 - separated networks example (optional in Tesira 2.4 and later)

 

Separated networks, direct connection example (optional in Tesira 2.4 and later)

Figure 3 - separated networks, direct connection example (optional in Tesira 2.4 and later)

Note: Remote expanders are PoE+ powered. A PoE+ network switch or inline PoE+ power source is required.

Implementing separated networks

Implementing separated networks is simple to do from the Device Maintenance dialog.

From the System menu, select Network then Perform Device Maintenance. In the Device Maintenance dialog, select a device in the Device List, then on the right-hand side of the dialog press the Network Settings button.

Device Maintenance - Network Settings

Figure 4 - Device Maintenance dialog

 

The Network Settings dialog will display the settings for the Control NIC by default.

In the drop down list in the Interface IP Configurations section, select the AVB media NIC.
(In a SERVER: avb_media_02 or avb_media_01; in a SERVER-IO: avb_media_13; in a TesiraFORTÉ: avb_media_0).

Network Settings

Figure 5 - select the AVB interface in Network Settings

 

Check the Enable box to activate the IP configuration for the AVB interface. This will enable the device's AVB network interface to discover Tesira's expander and control devices. 

Note the warning message, and ensure that the device's control and AVB media network interfaces are not connected to the same Ethernet broadcast domain. See the Essential rules section for more information.

Enable Interface AVB

Figure 6 - enable IP communication on the AVB network interface

IP Address setting

The default setting for the interface is to receive an IP address automatically (DHCP or Link Local). To manually configure with a static IP address, select Use the Following IP Address.

Ensure that the IP addresses used for two interfaces are on different subnets from each other, and pay particular attention when both interfaces are set to receive an IP address automatically.

See the Essential rules section for more information.

Essential rules

There are some simple but important rules to remember, all of which derive from standard networking practices.

If a Tesira SERVER, SERVER-IO or TesiraFORTÉ is configured to use separated control and AVB media networks:

  1. The control and AVB media networks must be physically or logically separated.
    If the two networks are connected to the same Ethernet broadcast domain, Tesira devices may become unresponsive.
     
  2. The IP addresses of each network must be in different (non-overlapping) subnets.
    If the IP addresses of the control network and AVB media network are in the same subnet, Tesira devices may become unresponsive.
     
  3. If the Tesira devices have both their control and AVB media networks configured to “Obtain an IP Address Automatically”, then a DHCP server must be present on at least one of the networks.
    • If neither network has a DHCP server, then both the interfaces will try to use IP addresses in the Link Local range of 169.254.xxx.xxx. This would violate rule 2.
       
    • Should this situation occur, the Tesira device will temporarily inhibit the AVB network interface.