This white paper lists the ports, protocols and bandwidth requirements used by the Allen & Heath AHM, dLive and Avantis systems. It gives IT managers an overview of the control and audio traffic on a network, so they can plan for sufficient hardware and network topologies in an efficient way, and ultimately ensure smooth operation of the system.
An AHM, dLive or Avantis system will present different RJ45 sockets to the integrator, each with a specific function and protocol, so we will examine these individually.
Network ports
Network ports are Gigabit Ethernet (1000BASE-T) and use the following protocols:
- AH-Net
- Device Discovery
- External Control
- DHCP
- HTTP
- NTP (AHM only)
- SMTP (AHM only)
AH-Net
AH-Net is a proprietary application layer network protocol for sending and receiving control data.
AH-Net uses a client / server model for passing control data. TCP port 51321 is used for server-side rendezvous endpoints. An ephemeral port is requested from the host system for outbound TCP client connections. For each TCP connection a UDP unicast connectionless datagram endpoint pair is also opened.
UDP Port Numbers start at UDP 51324 on each server and enumerate upwards for each new client accepted. The maximum number of connections is 40 for dLive and Avantis, 100 for AHM (resulting in UDP port range 51324-> 51424 on the server). On the client side, the UDP port number is ephemeral for each connectionless endpoint.
AH-Net allows 2 subtypes of packets to be sent / received: “NET” and “UTIL”, both of which have fixed header sizes with variable length data payloads. NET packets have a static header overhead of 12 bytes per message, UTIL packets have a static header overhead of 4 bytes per message. Data payloads are variable between 0->40,000 bytes from the application layer.
UDP data payload rates (excluding protocol overheads) are in the region of:
40 - 140 kB/s for each AHM System Manager connection.
335 kB/s for each dLive Surface or dLive Director connection.
~100 bytes sent and ~50 bytes received at connection and ~20 bytes per state change for each control in a Custom Control layout.
Metering overhead in Custom Control is per connected unit, for example:
128kB/s for each AHM-64 with one or multiple meters in the layout.
64kB/s for each AHM-32 with one or multiple meters in the layout.
32kB/s for each AHM-16 with one or multiple meters in the layout.
TCP data payload rates (excluding protocol overheads) for each IP Controller connected are:
13 * Number of meters displayed * 50 Bytes/s
Combined theoretical maximum transient network throughput across all connections from a dLive MixRack is approximately 380Mbit/s before becoming CPU bound.
Device Discovery
This protocol is used by A&H units and applications to find other units on the local sub-network.
Each unit on the network broadcasts a UDP “find” message once per second. The data payload of this message is the name of the unit, its type and information about the software that it is running. The maximum payload of this message is 116 bytes, the total message size is 158 bytes.
Each IP Controller on the network also broadcasts a “find” message once per second. The data payload of this message is the name of the unit. The maximum payload of this message is 36 bytes, the total message size is 78 bytes.
Device discovery is optional, and target device details can be entered manually by IP address if UDP broadcasts are blocked by a cross subnet device separation or switch settings.
External Control
TCP Rendezvous port 51325 (unsecured) or TLS/TCP port 51327 are used for accepting external / non AH-Net control messages typically sent by 3rd party applications. These are formatted as TCP encapsulated MIDI messages, and a control protocol document is available on the Allen & Heath website for each product. In AHM, this external control protocol can be disabled via System Manager.
Flow rates are dependent on client configuration.
An SSL certificate and key must be uploaded to the AHM unit for use with the TLS port.
DHCP
AHM, dLive and Avantis can act as DHCP client and be configured to receive their IP Address allocation from a DHCP server.
NTP
The AHM can be configured to get its time from NTP servers. These servers can be on the local network or on the Internet. Up to 3 servers can be configured to allow for outages. The time is synchronized approximately every 11 minutes when configured to use NTP. Time used is then UTC, with a configuration available for different time zones.
HTTP
AHM, dLive and Avantis have optional HTTP server listening on TCP Port 80 to facilitate firmware update. The TCP Port is disabled by default and can be enabled by hardware DIP switch settings as detailed in the user manuals.
SMTP
AHM processors can send emails via an SMTP server, if configured. These emails can be triggered from events such as notifications and errors or be scheduled via the “Events” scheduler.
Audio ports
SLink ports can automatically detect a connected device and switch to the appropriate Allen & Heath audio transport protocol. DX and dSnake modes operate at 802.3 IEEE Layer 2 for point to point audio transport using 100BASE-TX Fast Ethernet at full bandwidth. gigaACE modes operate at Layer 2 using Gigabit Ethernet 1000BASE-T and typical bandwidth of 680MBit/s.
For more information on audio transport protocols, please see this article. For information on running these transport protocols over a corporate network or VLANs, please click here.