Ethernet – the Most Popular Network

Originally developed in the 1970s, Ethernet has evolved from a 10 Mbps half-duplex network called shared Ethernet to a 1000 Mbps and beyond full-duplex switch technology called switched Ethernet.  Standardized by the Institute of Electrical and Electronics Engineer’s (IEEE) 802.3 committee, the word Ethernet is not mentioned in the standard.  However, it is commonly referred to as Ethernet and can be found everywhere – including automation systems.

Ethernet only defines the lower two layers (physical and data link) of the Open Systems Interconnection (OSI) Model but TCP/IP support (transport and network) is commonly found.  Ethernet’s long frame size (1500 bytes) can effectively support both information and control.  Data rates up to 1000 Mbps are frequently found and switch technology improves throughput and distance along with the convenience of multi-speed operation over the original 10 Mbps shared Ethernet.  Application layer protocols such as BACnet/IP, Modbus TCP, EtherNet/IP and ProfiNet can be found on top of 10/100/1000 Mbps switched Ethernet.  The openness of Ethernet has ensured its place as the most popular network.

Unmanaged Ethernet switches in the Skorpion and BAS Switch series provide a simple plug-and-play solution to connecting 10/100/1000 Mbps devices together.  They support auto-negotiation and auto-MDIX for hands-free operation.

For more sophisticated Ethernet networks, managed switches that support the Simple Network Management Protocol (SNMP) would be the choice.  These switches provide an abundance of features that can enhance performance and security.

Configurable switches fit between unmanaged and managed switches and allow for some customization of Ethernet port settings.  This could include data rate and duplex.

Media converters allow conversion between fiber optics and copper cabling.  Unlike fiber optic ports on a switch, these media converters do not store-and-forward frames and are therefore higher performing and suitable in redundant ring applications.

IP routers operate at layer three on the OSI model and allow two Ethernet networks to operate within one internetwork.  LAN to LAN or LAN to WAN connections is possible.

Power-over-Ethernet (PoE) injectors and splitters allow for the sharing of power and data over the same Ethernet cable.  Injectors source 48 volt power to end devices while splitters tap power from the cable to power non-PoE end devices.

Related Products

Product	Summary
Unmanaged Switches	Switching hubs offer greater network expansion than repeating hubs and multi-speed operation. A plug-and-play unmanaged switch offers installation convenience by not requiring any configuration without a sacrifice in performance. Some models include features such as Auto-MDIX and Auto-negotiation. See Products
Managed Switches	The ultimate in performance and flexibility can be found in a SNMP compliant managed switch. By configuring the switch through either a web page or console screen, features such as Virtual LANS, Quality of Service, Cable Redundancy and Port Mirroring can be invoked. See Products
Configurable Switches	A configurable switch fits in between an unmanaged and managed switch. Although a configurable switch does not support the SNMP protocol, several other features usually found on managed switches can be found on an configurable switch. See Product
Media Converters	Our media converters offer the lowest latency since they are pure media converters and not 2-port switches. Conversion from copper to fiber optic cabling is possible without the loss of Auto-negotiation features. See Product
Routers	Ethernet routers allow either a LAN to LAN connection using Ethernet or a LAN to WAN connection using either an internal or external modem. Connection to the Internet is possible. Our routers feature a built-in stateful firewall, DHCP server, dial-in and dial-out functionality. Routers are needed to provide remote access to automation equipment. See Products
PoE Injectors	Within the IEEE 802.3af Power Over Ethernet standard, the EIPE Power Injector functions as power sourcing equipment (PSE) and will fully power one powered device (PD) by supplying 15.4 W of power. The advantage of the EIPE is that it can be powered by a 24 VAC/VDC supply and therefore does not require a 48 VDC source to generate the required PoE voltage. See Products