AVB与TSN关键概念与协议族

TSN基础概念

• TSN flow(Stream) （流）：用于描述两个端设备之间的对时间有严格要求的关键通信数据。每个flow在中间网络设备上传输都有严格的时间需求，每个flow能够被网络设备唯一标识（通过Stream ID）。
• End divices（端设备）：代表TSN flows的源设备和目的设备，端设备上运行着有确定性通信需求的应用。端设备跟据角色不同也被称为Talker（发送端）与Listener（接收端）。
• Bridges（以太网交换机）：能够依据调度表，转发或接收TSN flow帧数据的交换机。

关键组件

AVB协议族

 802.1AS Timing and Synchronization for Timing-Sensitive Applications
 802.1Qat Stream Reservation protocol(SRP)
 802.1Qav Forwarding and Queuing Enhancements
 802.1BA lists of standards and definition of profiles fro AVB systems

TSN协议族

Core standards (currently working)
 802.1ASbt Timing and Synchronization
 802.1Qcc Stream Reservation Protocol
 802.1Qbv Enhancements for scheduled traffic
 802.1Qbu Frame Preemption
 802.1Qca Path control and Reservation
 802.1CB Frame Replication and Elimination for reliability

IEEE协议族

• IEEE 802.1BA-2011：Audio Video Bridging (AVB) Systems
• IEEE 802.1Q-2011 Section 34 and 35
  • Sec 34：IEEE 802.1Qav (Forwarding and Queueing for Time-sensitive Streams)
  • Sec 35：IEEE 802.1Qat (Stream Registration protocol)
• IEEE 802.1AS gPTP
• IEEE 1722 AVTP Layer 2 Transport Protocol for Time-Sensitive Applications in Bridged Local Area Networks
• IEEE 1722.1 Device Discovery, Connection Management and Control for 1722

TSN主要的projects（整合）：

queuing and forwarding

• 802.1Qav credit-based shapers
• P802.1Qbu preemption
• P802.1Qbv time-aware queuing
• P802.1Qch cyclic queueing
• P802.1Qci input gating
• P802.1CB seamless redundancy

registration and reservation

• 802.1Qat – a distributed “stream reservation protocol”
• extended in new P802.1Qcc to support preemption, scheduling, centralized control, and interaction with higher layer IETF services
• enhanced SRP (802.1Qcc)

time synchronization

• IEEE Std 802.1AS

overall system architecture

• IEEE Std 802.1BA

参考文献

1. Time-Sensitive Networking Task Group
2. A Proper TSN Driver Is Being Worked On For The Linux Kernel (Time Sensitive Networking)