Author: Barbara Schmitz, Chief Marketing Officer, MEN Mikro Elektronik
Ethernet as a communication medium is perhaps the most important element of the CompactPCI Serial specification beside PCI Express, SATA and USB. Ethernet can be implemented for low acquisition costs, is well-established, future-oriented, versatile and easy-to-handle. It allows to build up systems without complex switch and bridge technology.
Ethernet interface boards (like the G211 from MEN) extend the number of available boards of the system slot CPU on a separate slot. The connection is done via PCI Express on the P1 connector. Ethernet mezzanine boards (such as the GM1 from MEN) are plugged directly onto the system slot CPU and lead up to eight Ethernet ports to the backplane via the dedicated P6 connector. They are used for the communication with (intelligent) peripheral slot boards in a star or a mesh architecture. Switch boards offer additional possibilities. Using an Ethernet switch in the system slot, multicomputers with CPU boards in the peripheral slots can be built up – also via the P6 connector. A switch in the peripheral slot (such as the G301 from MEN) on the other hand offers the typical characteristics needed for connecting external devices – without software overhead.
The G301 provides four Gigabit ports at the front panel, which only need one slot in the system both for the RJ45 and the M12 version. The fifth port is connected to the system slot CPU via PCI Express. An optional sixth port is available on the Ethernet connector P6 and can be used to connect internal and external communication structures.
All four front connections support Power over Ethernet (PoE) and are able to supply up to four external devices simultaneously according to Class 1 (4 W) and Class 2 (7 W) as Power Source Equipment (PSE). G301 is an "unmanaged" switch, i.e. it is not detected by other CompactPCI Serial boards and does not need its own software. "Fixed managed" configurations can optionally be stored in the EEPROM.