“No car will be an island”
eeNews Europe: What standardization is necessary to anchor Ethernet in automotive applications?
Steve Carlson: First, we all should recognize that Ethernet as it exists today is capable of executing full-duplex, absolutely deterministic transmission between endpoints. It also provides 100% bandwidth utilization, which is critical for the automotive industry to roll out future applications. The implementation challenges of Ethernet in automotive are identical to those any networking technology handling the growing amount of data generated by automotive systems. These challenges are network architecture issues such as what happens when the data reaches a switch. The standardization activity for automotive we have in process today is very much focused defining a PHY layer for 1 Gb/s transmission over a single, unshielded twisted-pair wire and how to provide that service in the harsh electro-magnetic environment of an automobile. This PHY will give automotive designers the minimum number of pairs at the lowest possible weight and cost. We’re also standardizing, in a different 802.3 project, a power delivery technology that can be used to run the devices at the end of the data line. This means a single twisted pair can supply a gigabit of data and the power to run whatever endpoint device may be at the other end of the line.
eeNews Europe: What is Ethernet’s roadmap for moving from its automotive applications today – infotainment in the first place – into real-time applications such as drive-by-wire and brake-by-wire?
Carlson: Ethernet deployment is already well beyond infotainment. It has been in the diagnostic port of automobiles for a number of years and we’re already seeing it deployed as the communication link in camera systems. Standardization in this application is very important to OEMs because unlike competing LVDS (Low-Voltage Differential Signaling) technologies, Ethernet offers compatibility with systems outside the automobile. The next Ethernet application will be to interconnect multiple ECUs (Electronic Control Units) so all the ECUs will be have a full-duplex, high-bandwidth network communications capability. There are no reliability issues here. Ethernet is more reliable for data transport than any other technology, and implementers can chose the level of reliability by utilizing higher-layer network protocols, e.g. TCP/IP.
But it will take years for these changes to reach the marketplace because the automobile industry has a six-year design cycle. They make changes over a long period of time because automotive design is quite complex. In our IEEE task forces, we have automobile manufacturers from around the globe as well as Tier 1 OEMs. Their intention is that they eventually will be using Ethernet everywhere because they don’t want to be tied to proprietary technologies, they are looking a getting more performance per dollar and – this is very important – from a networking perspective, the car will no longer be a self-contained island. It will communicate far more with the outside world and therefore must use global standards.
eeNews Europe: Does Ethernet AVB offer any advantages over MOST?
Carlson: MOST is a proprietary technology based on a ring topology and it is used almost exclusively for infotainment. While it is true that MOST has devised a way to transport Ethernet frames, it still isn’t Ethernet. MOST has two very real challenges: It is a proprietary technology; and, it has been optimized for infotainment. The automotive industry is already having a difficult time patching together a number of subnetworks – all of which do just one thing—into a reliable networking environment for the entire vehicle. This problem is only going to get worse as the systems need to communicate more and more with each other. The situation we see in the automotive industry today is very similar to the network wars of the 1980s, where Ethernet won because it is the most flexible. Ethernet’s mantra has always been “faster, cheaper, more reliable.”
eeNews Europe: Does using Ethernet as a network backbone increase the likelihood of a “single point of failure?”
Carlson: One of the things that 802.1 AVB bridging brings is the ability to have a redundant link in place. You can actually have two redundant Ethernet links so if one is damaged the other will still be running to control the car properly. Other technologies do not offer this.
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