Issue link: https://www.e-digitaleditions.com/i/1347119
12 I ICT TODAY When past upgrades were made from fieldbus to 4-pair Ethernet, there was no question that new cabling infrastructure would be required. This is not a foregone conclusion today with SPE. While the cabling infrastructure for SPE is newly standardized by TIA and IEC, there is the possibility that existing infrastructure could meet the requirements of SPE for the application being considered. Project teams should take into careful consideration the gauge, condition, and balance of the legacy wires, along with the topology used for the legacy system. Testing systems are already available to help evaluate the performance of the cabling infrastructure and understand whether cable reuse will be an option for the client. As with 4-pair Ethernet, the most common topology will be a star topology where devices have a point-to-point connection to the switch with structured links between them, depending on the distance and system require- ments. Single-pair Ethernet delivers point-to-point con- nectivity across one kilometer and up to 10 structured links between the switch and the edge device. However, a second topology is standardized that provides a true multi-drop topology that allows one SPE switch port to connect up to 8 devices across a 25 meter trunk. In this topology, each device "taps" into the trunk cable. This does not require dual ports on the device as is common with traditional Ethernet ring and bus architectures. There may be lingering questions about the security of connecting more edge devices onto an IP network: • In the case that that every individual device is IP addressable, will the network be at greater risk? This is a good question and should be investigated in its specific application for any architecture that is deployed. One way to begin answering this question is by comparing the systems that this will be replacing. • Did the existing systems connect to the network in any way (e.g., through gateway systems)? • How accessible were these systems? • What network security architecture was in place over the existing systems? • What exceptions were built into the network security to allow legacy systems to function? Typically, a network infrastructure with a higher amount of complexity and more legacy technologies will be more difficult to secure and will have increased security risk. Adding more IP devices in the right way, while making the TCP/IP network larger, can serve to simplify the network. As a result of simplifying the network, a simpler and more robust security architecture can be maintained. Applications for Single-Pair Ethernet Single-pair Ethernet does not belong to a single industry. It was standardized by IEEE 802.3, which is the same working group of the IEEE that has defined and standardized wired Ethernet for LAN technology. Subse- quently, SPE has been incorporated into standards by the IEC, TIA, BICSI, automotive, industrial, and process standards organizations. As a physical layer technology that enables the expansion of Ethernet, there are several use cases and applications for SPE that can be anticipated. One of the first applications for SPE will be for the process industry. Single-pair Ethernet will apply to both hazardous environments represented by oil, gas, and chemical plants, as well as non-hazardous process A second topology is standardized that provides a true multi-drop topology that allows one SPE switch port to connect up to 8 devices across a 25 meter trunk.