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Multicast Switching Protocol


Overview

Switching sources in a Just Add Power Multicast Switching system involves changing the multicast IP of the Receiver - called a Channel - to match the multicast IP of the Transmitter it wants to watch.

Changing the Channel in a Just Add Power Multicast Switching system can be done in various ways depending on the needs of the control system or end user.

In Basic Mode, all 4 services - Audio, Video, USB, Serial - are set to the same Channel. In Advanced Mode, each service can be set to a unique Channel. All devices must be in the same Mode.

Use our AMP Software to setup Just Add Power devices for Multicast Switching.


Requirements

  1. Only compatible with 3G and MaxColor devices
  2. justOS firmware B2.1.0 or greater
  3. All units in the same VLAN with the same IP scheme.

Please see the article on Multicast Switching for Single VLAN Implementations for information on how to setup the network.


Concept

An audio/video signal in a Multicast Switching system is distributed according to the multicast IP assigned to the signal. The full multicast IP is distilled down to a single Channel number for simplicity of programming. Audio and video have separate multicast IPs, making audio and video separately routable.

Each Transmitter has a unique multicast IP that distinguishes it from all other Transmitters on the network.

The multicast IP of a Receiver is altered to match the multicast IP of the Transmitter it wants to watch.

Default Multicast IPs

Basic Mode - audio and video switch together (default)

  • Video - 239.92.0.0
  • Audio - 239.92.0.0

Advanced Mode - audio and video switch together or separately

  • Video - 239.92.0.0
  • Audio - 239.93.0.0

Multicast IP to Channel Translation

The first 2 octets of the multicast IP must be the same for all devices. The first octet can be changed, but must be the same value on all devices. The second octet is used to distinguish between different services - audio or video - on the same unit.

The second 2 octets are unique to each Transmitter and identify it on the network. They directly relate to the Channel number of the Transmitter.

  • Channel numbers are integers ranging from 0 to 9999
  • The 4-digit Channel translates to the last 2 octets of the multicast IP:
    • Channel 0000 --> 239.92.00.00
    • Channel 99 --> 239.92.0.99
    • Channel 100 --> 239.92.1.00
    • Channel 9999 --> 239.92.99.99

Basic Mode Commands

AMP Alternate Configuration builds a system in Multicast Basic Mode and applies Channels and Management IPs. The commands below are needed if not running AMP.

All commands are case-sensitive.

Set Basic Mode (default)

DEFAULT. Set once. All devices must have the same Mode. All services switch together.

channel mode basic

Set Audio & Video Channel

Set once on a Transmitter. Send to a Receiver to switch audio and video. Variable X is an integer from 0-9999.

channel X

Set Management IP (TX & RX)

Set IP address, subnet mask, and default gateway for network access. Example uses IP 172.17.128.1, mask 255.255.0.0, gateway 172.17.255.254

astparam s ip_mode static;astparam s ipaddr 172.17.128.1;astparam s netmask 255.255.0.0;astparam s gatewayip 172.17.255.254;astparam save


Advanced Mode Commands

AMP Alternate Configuration builds a system in Multicast Basic Mode. The Management IPs can stay the same, but the conversion to Advanced Mode must be done manually.

All commands are case-sensitive.

Set Advanced Mode

Set once. All devices must have the same Mode. Allows all services to switch separately.

channel mode advanced

Set Audio Channel

Set once on a Transmitter. Send to a Receiver to switch audio. Variable X is an integer from 0-9999.

channel -a X

Set Video Channel

Set once on a Transmitter. Send to a Receiver to switch video. Variable X is an integer from 0-9999.
channel -v X

Set USB Channel

Set once on a Transmitter. Send to a Receiver to switch USB control. Variable X is an integer from 0-9999.
channel -u X

Set Management IP (TX & RX)

Set IP address, subnet mask, and default gateway for network access. Example uses IP 172.17.128.1, mask 255.255.0.0, gateway 172.17.255.254

astparam s ip_mode static;astparam s ipaddr 172.17.128.1;astparam s netmask 255.255.0.0;astparam s gatewayip 172.17.255.254;astparam save


HTTP API

The full HTTP API for justOS is available here


Web Interface

The web interface only allows Basic Mode options

Set Audio & Video Channel

Set once on a Transmitter. Send to a Receiver to switch audio and video. Variable X is an integer from 0-9999.

On the Network tab, set the Multicast Channel and select Apply. Channel is updated immediately.

Set Management IP (TX & RX)

Set IP address, subnet mask, and default gateway for network access. Example uses IP 172.17.128.1, mask 255.255.0.0, gateway 172.17.255.254

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