“Networks based on Ethernet and Internet Protocol (IP) are ubiquitous. You can find them in standard computer networks as well as in automotive, IoT and various automation applications, it has been around for almost 50 years. Microchip Technology senior manager Henry Muyshondt explained.
“
This article was written by Microchip Joe Bush
Networks based on Ethernet and Internet Protocol (IP) are ubiquitous. You can find them in standard computer networks as well as in automotive, IoT and various automation applications, it has been around for almost 50 years. Microchip Technology senior manager Henry Muyshondt explained.
Ethernet provides scalable bandwidth from several megabits per second to several gigabits per second over several different physical media, and a proven software stack is available to ensure reliable transmission over the media.
Security is an essential element of this technology, and there is a well-defined framework to include it in Ethernet-based systems.
Ethernet’s service-oriented architecture helps with the complexities through packetization and data management. Many systems can reuse unified communications mechanisms to easily communicate with each other and allow services to be easily moved to their appropriate locations in the network.
In the past, many different technical protocols have been used to interconnect different devices. In the field of industrial automation, there are various fieldbuses, Ethercat, RS-485, UART, etc. In the automotive domain, using MOST, CAN, LIN and other networks, complex gateway devices are required to communicate between domains. In the computer server market, we see I2C, GPIO, SPI and even CAN from the automotive world being used to manage various subsystems.
Figure 1. Illustrates the benefits of coherent Ethernet architecture
Each of these uses its own hardware interface and implements a different software stack. EMC behavior varies. An all-Ethernet architecture has many advantages because the same protocol can be used regardless of the physical layer. Ethernet frames look the same whether they are transmitted at 10Mbit/s or 10Gbit/s.
When expanding bandwidth for specific applications, complex gateways are not required. Often, a single switch can be equipped with PHY Chips that operate at different speeds, and frames can move seamlessly from one domain to another without modifying the data.
The ubiquitous Ethernet architecture simplifies the design, configuration and control of many different applications in the industrial, computer or automotive fields. The same technical expertise can be used in different markets. No matter how much data needs to be transferred, the same mechanism can be used because Ethernet frames are not modified for different speed classes. In addition, there is a large ecosystem of hardware and software suppliers for the Ethernet communication infrastructure.
The Ethernet world has designed an architecture to ensure the security and privacy of information transmitted over Ethernet links, and this security infrastructure is well known.
10BASE-T1S – the new IEEE standard
The IEEE has developed a new variant of the Ethernet standard that provides 10Mbit/s of bandwidth over a single pair of physical layers. The specification is called IEEE Std 802.3cg-2019. Details are complete and the specification should be released in early 2020. This specification extends the scope of modern Ethernet physical layers at the lower end of the bandwidth range.
One variant specified by the IEEE standard is called 10BASE-T1S. The S stands for short range and also defines a long range variant called 10BASE-T1L which has a maximum range of 1 km. This article focuses on 10BASE-T1S.
10BASE-T1S uses a multipoint topology where each node is connected using a single cable. This eliminates the need for switches and reduces the number of cables. Each cable uses only one pair of wires instead of the four used in typical Ethernet cables, and the interconnection can even be implemented on a printed circuit board. The standard specifies that at least eight nodes can be connected, but more nodes can be connected. It also specifies a bus length of 25m, with 10cm stubs for each node. All nodes share 10Mb/s bandwidth.
Figure 2. Shows the concept of a shared bus
The standard also specifies an arbitration scheme called Physical Layer Conflict Avoidance (PLCA), which makes the best use of available bandwidth while reducing latency and improving Quality of Service (QoS).
Microchip has been a major contributor to the IEEE standards process, supporting not only chips but also application boards and the tools needed to simulate, implement and analyze networked systems.
thingManagement Layer Conflict Avoidance (PLCA) Details
After PLCA is enabled, only the PHY devices that have the opportunity to transmit are allowed to send data. Transmission opportunities are allocated in a round-robin fashion. Each PHY can transmit during its transmit opportunity and can then transmit frames of information. A new cycle starts when the master node sends a beacon. Figure 3 illustrates the process.
In practice, it has been observed that the round-trip delay between two nodes is less than half a millisecond, and almost full speed of 10Mbit/s can be obtained when using the iperf3 tool for measuring the maximum achievable bandwidth on IP networks.
Application field
10BASE-T1S technology is gaining attention in building/industrial automation, automotive and computer applications.
In industrial applications, this interconnect scheme has been deployed in many applications to provide in-system management and connect many devices such as fans, temperature sensors, voltage monitors, etc. Even simple devices such as switches, buttons, lights, etc. can be solved using an Ethernet solution.
In automobiles, various sensors require lower bandwidth and benefit from a network architecture that makes the subsystems more easily scalable to accommodate different vehicle deployments.
Figure 3. When the master sends a beacon, a new cycle begins
In the computing world, 10BASE-T1S is required for in-system management interfaces inside servers and switches, and for applications used to configure and monitor large servers. Similar to the industrial world, various devices such as fans, temperature sensors, and voltage monitors can be easily accessed using Ethernet.
Although the transmission of power over data lines (PoDL) has not yet been fully standardized, several working groups are already working on it, and the IEEE is expanding the 802.3cg specification to include the addition of PoDL. The 10BASE-T1S physical layer is AC coupled, so it can power remote devices.
in conclusion
10BASE-T1S has the following key features to extend Ethernet technology to new applications:
multipoint physical layer
no conflict
Efficient Bandwidth Utilization
Deterministic and low latency
Security Mechanism
The ubiquitous Ethernet architecture simplifies the design, configuration and control of many different applications in the industrial, computer or automotive fields.
10BASE-T1S components are on the market and are already being implemented in new system designs.
“Networks based on Ethernet and Internet Protocol (IP) are ubiquitous. You can find them in standard computer networks as well as in automotive, IoT and various automation applications, it has been around for almost 50 years. Microchip Technology senior manager Henry Muyshondt explained.
“
This article was written by Microchip Joe Bush
Networks based on Ethernet and Internet Protocol (IP) are ubiquitous. You can find them in standard computer networks as well as in automotive, IoT and various automation applications, it has been around for almost 50 years. Microchip Technology senior manager Henry Muyshondt explained.
Ethernet provides scalable bandwidth from several megabits per second to several gigabits per second over several different physical media, and a proven software stack is available to ensure reliable transmission over the media.
Security is an essential element of this technology, and there is a well-defined framework to include it in Ethernet-based systems.
Ethernet’s service-oriented architecture helps with the complexities through packetization and data management. Many systems can reuse unified communications mechanisms to easily communicate with each other and allow services to be easily moved to their appropriate locations in the network.
In the past, many different technical protocols have been used to interconnect different devices. In the field of industrial automation, there are various fieldbuses, Ethercat, RS-485, UART, etc. In the automotive domain, using MOST, CAN, LIN and other networks, complex gateway devices are required to communicate between domains. In the computer server market, we see I2C, GPIO, SPI and even CAN from the automotive world being used to manage various subsystems.
Figure 1. Illustrates the benefits of coherent Ethernet architecture
Each of these uses its own hardware interface and implements a different software stack. EMC behavior varies. An all-Ethernet architecture has many advantages because the same protocol can be used regardless of the physical layer. Ethernet frames look the same whether they are transmitted at 10Mbit/s or 10Gbit/s.
When expanding bandwidth for specific applications, complex gateways are not required. Often, a single switch can be equipped with PHY chips that operate at different speeds, and frames can move seamlessly from one domain to another without modifying the data.
The ubiquitous Ethernet architecture simplifies the design, configuration and control of many different applications in the industrial, computer or automotive fields. The same technical expertise can be used in different markets. No matter how much data needs to be transferred, the same mechanism can be used because Ethernet frames are not modified for different speed classes. In addition, there is a large ecosystem of hardware and software suppliers for the Ethernet communication infrastructure.
The Ethernet world has designed an architecture to ensure the security and privacy of information transmitted over Ethernet links, and this security infrastructure is well known.
10BASE-T1S – the new IEEE standard
The IEEE has developed a new variant of the Ethernet standard that provides 10Mbit/s of bandwidth over a single pair of physical layers. The specification is called IEEE Std 802.3cg-2019. Details are complete and the specification should be released in early 2020. This specification extends the scope of modern Ethernet physical layers at the lower end of the bandwidth range.
One variant specified by the IEEE standard is called 10BASE-T1S. The S stands for short range and also defines a long range variant called 10BASE-T1L which has a maximum range of 1 km. This article focuses on 10BASE-T1S.
10BASE-T1S uses a multipoint topology where each node is connected using a single cable. This eliminates the need for switches and reduces the number of cables. Each cable uses only one pair of wires instead of the four used in typical Ethernet cables, and the interconnection can even be implemented on a printed circuit board. The standard specifies that at least eight nodes can be connected, but more nodes can be connected. It also specifies a bus length of 25m, with 10cm stubs for each node. All nodes share 10Mb/s bandwidth.
Figure 2. Shows the concept of a shared bus
The standard also specifies an arbitration scheme called Physical Layer Conflict Avoidance (PLCA), which makes the best use of available bandwidth while reducing latency and improving Quality of Service (QoS).
Microchip has been a major contributor to the IEEE standards process, supporting not only chips but also application boards and the tools needed to simulate, implement and analyze networked systems.
thingManagement Layer Conflict Avoidance (PLCA) Details
After PLCA is enabled, only the PHY devices that have the opportunity to transmit are allowed to send data. Transmission opportunities are allocated in a round-robin fashion. Each PHY can transmit during its transmit opportunity and can then transmit frames of information. A new cycle starts when the master node sends a beacon. Figure 3 illustrates the process.
In practice, it has been observed that the round-trip delay between two nodes is less than half a millisecond, and almost full speed of 10Mbit/s can be obtained when using the iperf3 tool for measuring the maximum achievable bandwidth on IP networks.
Application field
10BASE-T1S technology is gaining attention in building/industrial automation, automotive and computer applications.
In industrial applications, this interconnect scheme has been deployed in many applications to provide in-system management and connect many devices such as fans, temperature sensors, voltage monitors, etc. Even simple devices such as switches, buttons, lights, etc. can be solved using an Ethernet solution.
In automobiles, various sensors require lower bandwidth and benefit from a network architecture that makes the subsystems more easily scalable to accommodate different vehicle deployments.
Figure 3. When the master sends a beacon, a new cycle begins
In the computing world, 10BASE-T1S is required for in-system management interfaces inside servers and switches, and for applications used to configure and monitor large servers. Similar to the industrial world, various devices such as fans, temperature sensors, and voltage monitors can be easily accessed using Ethernet.
Although the transmission of power over data lines (PoDL) has not yet been fully standardized, several working groups are already working on it, and the IEEE is expanding the 802.3cg specification to include the addition of PoDL. The 10BASE-T1S physical layer is AC coupled, so it can power remote devices.
in conclusion
10BASE-T1S has the following key features to extend Ethernet technology to new applications:
multipoint physical layer
no conflict
Efficient Bandwidth Utilization
Deterministic and low latency
Security Mechanism
The ubiquitous Ethernet architecture simplifies the design, configuration and control of many different applications in the industrial, computer or automotive fields.
10BASE-T1S components are on the market and are already being implemented in new system designs.
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