Unique MAC Addresses-New IE Products


Thread Starter

Willy Smith

Hi I must have missed something here. May I ask why we have a requirement for an official set of addresses. I assume these addresses represent I/O points? Bob Pawley

Hullsiek, William

Each address represents a unique end-node, or interface-point for a router. This allows Ethernet to be 'plug and play' or 'plug and pray' as possible. An Ethernet packet, consists of approximately 1520 octets or bytes. If you encapsulate a digital i/o, of 2 bits per signal, you can move 1520 * 8 / 2 = 6080 points per packet. (This assumes no overhead). State of the shelf today is 1 Gigabyte per second, so if you are running raw Ethernet packets, you can move alot of data quickly and reliable. But this is a stochastic process not a deterministic process, i.e., you play the odds that things work well most of the time. - Billiam -
No, the addresses represent the address of an ethernet interface (such as a network adaptor card in a PC). Every ethernet interface made has a unique address built into the hardware. What this has to do with this list I do not know, this is what the electronic product development engineer needs to know, not the end user, the point about having built in unique adresses is that the end user need know about or bother about it (go on, how many of you knew your network card had its own unique ethernet address). What process engineers should be aware of is that intelligent hubs can be hard wired to route these adress's to specific ports. This is generally done automaticly, the hub monitors where packets come from to build its own routing table, but in the case that ethernet becomes widely used for industrial I/O, I think some hard wiring will be a good thing.

Dave Ferguson

Some of us who want to understand our jobs completely did and do know this. Maybe your response and attitude is why so much is taken for granted in projects and why so many times projects end up over budget. You better know a little about everything especially when it comes to TCP/IP and Ethernet communications or the rest of us will enjoy your old job.... Just my humble opinion........"Never stop Learning, education is lifelong........." Dave Ferguson Blandin Paper Company UPM-Kymmene DAVCO Automation