The IEEE 802.1AS protocol software has a modular structure and separates the media independent and media dependent layer, insuring fast integration into the target system. Target platform dependent parts are within well-defined units interfacing to the protocol software, which considerably simplifies porting to the target system. This also includes the connection to the network interface, the IEEE 1588 RTC (Real time clock) and the timestamp unit of the hardware.

Ixxat IEEE 802.1AS Protocol Stack

The 802.1AS protocol software is available as a time-aware slave-only end station, which is the receiver of the time-synchronization information provided by a grandmaster.
The software is provided as ANSI-C code similar to MISRA-C 2012.

IEEE 802.1AS Architectuur

Features and Benefits

• Time-aware end station synchronizing the local RTC
• Automotive grade startup time: Synchronization startup time below one second
• Similar to MISRA-C 2012
• 802.3 full-duplex Ethernet (media dependent layer)
• Best master clock algorithm
• Optional disabling of BMCA
• Simple API for interfacing the application

IEEE 802.1AS Set-up

The 802.1AS-2011 standard specifies the protocol and procedures for the transport of time information over bridged networks and is derived as a profile from the original standard for precision time synchronization, the IEEE1588-2008 standard. The 802.1AS-2011 standard is part of the AVB standard and provides the time synchronization needed within AVB networks, further extended by the IEEE 802.1 Time Sensitive Networking (TSN) Task Group.

Within an AVB network only time-aware nodes are allowed. The 802.1AS-2011 standard defines two types of time-aware systems: a time-aware end station and a bridge. The time-aware end station is most likely the consumer of the time-synchronization information, otherwise the grandmaster.

A bridge can be the grandmaster and provides the time information on all ports, or it can be a consumer of the time-synchronization information. In that case, a bridge acts like a Boundary Clock, compared to the IEEE 1588-2008 standard. The time synchronization information synchronizes the bridge on one port and all other ports distribute the information to other time-aware nodes. The transportation of time-synchronization information across a bridge corresponds to the behavior of a Transparent Clock defined within the IEEE 1588-2008 standard.

The 802.1AS-2011 standard separates time synchronizing tasks and network communication. At this, the media independent layer handles the information which provides the time e.g. to the media clock. The media dependent layer provides the network access and defines the used network protocol. The synchronization messages received and transmitted on the network may differ between different communication technologies. Therefore creating corresponding messages and getting the time-synchronization information data is defined within each media dependent layer. The 802.1AS-2011 standard provides a well-defined interface between the media independent and media dependent layer.

Additional services

The services below are not included in the content of standard delivery.

Maintenance agreement

As a supplement to the software package, Ixxat offers a maintenance agreement that includes the provision of the following services for the term of the agreement:

• Free updates and troubleshooting
• Adaptation to the latest standard
• Technical support

Code introduction

We also offer a one-day introduction to the code that focuses on interfaces, processes and data flows in the IEEE 802.1AS software. Specific questions concerning the adaptation can also be answered while direct adaptations to the code can also be carried out.

Implementation support

As an additional program offering, we can also handle the adaptation, implementation and testing of the IEEE 802.1AS software on your system.