Milan

How Does it Work

The scope of this page is to provide a high-level guide for designing Milan products. It describes an overview of AVB protocols, the Milan profile definitions, AVB device terminology, network topologies, and general best practices.

Milan Certification ensures seamless interoperability, robust connectivity, and maximum convenience, guaranteeing that every device will connect with any other device using standardized formats and definitions.

Benefits and Adoption of AVB

AVB is based on open-source standards that are not owned or licensed by any one entity, ensuring its long-term viability. Many Pro Audio companies have integrated AVB into product designs as the preferred choice for distributing digital audio signals and control.

Implementation Standards for TSN Technology

Milan adds essential agreements about the implementation of TSN technology, including requirements for compatible and compliant media formats, media-clocking, redundancy, and controller software. These requirements are implemented correctly through compliance testing and certification of end devices.

Universal Connectivity Protocols

Every device will connect with any other device using a variety of agreed-upon formats and market-required definitions in the protocol.
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AVB/TSN

Audio Video Bridging (AVB) is a subset of Time-Sensitive Networking (TSN), defined by a series of IEEE standards.

These standards are designed to facilitate the reliable transport of high-performance audio, video, and other media formats over an Ethernet Local Area Network (LAN). AVB standards specify how to efficiently distribute multi-channel signals across devices using a single network connection.

Overview – AVB/TSN and Milan

AVB (Audio Video Bridging) is now often referred to as AVB/TSN or just TSN (Time Sensitive Networking). In fact, MILAN builds on top of AVB, and AVB builds on top of TSN.

Purpose of AVB/TSN Standards

AVB/TSN Standards specify additional capabilities to the Ethernet network to ensure media transportation with low latency and deterministic delivery between devices.

Key Enhancements of the AVB/TSN Standards Family

  1. Precise Timing: Supports low-jitter media clocks and accurate synchronization of multiple streams.

  2. Stream Reservation Protocol: Allows an application on an endpoint device to reserve the network bandwidth necessary along the complete path from AVB talker to AVB listener.

  3. Queuing and Forwarding Rules: Ensure that a stream will pass through the network within the time specified by the reservation.

AVB key components

AVB is defined by these key components:

  • Stream reservation protocol (SRP)
  • Forwarding and Queuing for Time-Sensitive Streams (FQTSS), or traffic shaping
  • Generalized Precision Time Protocol (gPTP), or time synchronization
  • Audio Video Discovery, Enumeration, Connection Management (AVDECC)
  • Audio Video Transport Protocol (AVTP)

Stream Reservation Protocol (SRP)

Stream Reservation Protocol (SRP) is part of a standard (IEEE 802.1Q-2018) that specifies the end-to-end management of resource reservations for data streams requiring guaranteed Quality of Service (QoS) in Local Area Networks (LANs). The protocol allows stream endpoints to register their ability to send or receive specific streams and specifies how that information propagates through the network. SRP encompasses Multiple VLAN Reservation Protocol (MVRP) and Multiple Stream Reservation Protocol (MSRP)

Multiple VLAN Reservation Protocol (MVRP)

Multiple VLAN Reservation Protocol (MVRP) is a standards-based Layer 2 network protocol for automatic configuration of VLAN information on switches. Within a layer 2 network, MVRP provides a method to dynamically share VLAN information and configure the needed VLANs. AVB automatically uses MSRP to set up the necessary stream reservations as the user makes connections.

In practice, the necessary VLANs for successful transport of AVB data are automatically configured by the AVB switch (which can also configure non-AVB devices). Users do not have to manually configure VLANs for successful transport of AVB data.

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AVB Network Considerations

Only network switches that have been Avnu-certified should be considered when designing or operating AVB networks.

The latest list of Avnu-certified hardware, including network switches.

Multiple Stream Reservation Protocol (MSRP)

Multiple Stream Reservation Protocol (MSRP) is a signaling protocol that allows nodes communicating on a network to reserve network resources and ensure an adequate quality of service level to communicate data packets. For time-sensitive data, such as audio and video content, this protocol guarantees that the necessary bandwidth is available and prioritizes its transmission over other network traffic. AVB automatically uses MSRP to set up the necessary stream reservations as the user makes connections.
To initiate a transfer, AVB devices capable of transmitting AVB streams, or talkers, will advertise their available AVB streams on the network. AVB devices capable of receiving AVB streams, or listeners, will respond over the network that they are available. Once a connection is made between a talker and listener, MSRP will ensure the required bandwidth is available to successfully transport the stream from the talker to the listener. An end-to-end signaling mechanism to detect the success or failure of the effort is also provided.