What would be a non-transparent bridge?

A "Non-transparent bridge" generally means a Source Routing Bridge (SRB), as used with Token Ring networks. These bridges were "visible" (i.e., not transparent); end stations expressly specified the path each frame would take via a list of ring numbers and bridge numbers. SRBs are no longer used today. (There is a complete discussion of Source Routing Bridges in Chapter 6 of "The Switch Book".)

Trivia: A "transparent" object is one which is physically present, but can be treated as if it was not (e.g., a transparent bridge). The opposite is a "virtual" object, which is not physically present, but can be treated as if it was.

-- Rich Seifert Networks and Communications Consulting 21885 Bear Creek Way (408) 395-5700 Los Gatos, CA 95033 (408) 228-0803 FAX

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Sorry, I meant that SRBs are no longer used for new installations. Of course, legacy networks may last for a *long* time; I know of a few places that still used ARCnet.

-- Rich Seifert Networks and Communications Consulting 21885 Bear Creek Way (408) 395-5700 Los Gatos, CA 95033 (408) 228-0803 FAX

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Oh yes they ARE still used today. I know several fortune 50 comnaies that are still heavily using token ring and still use SRB's. Heck, my local hospital still uses 4mbps token over type1 cable and SRB's.

Sheesh. Ya, come to think of it I know of a place that does too. Arcnet over fiber at that.

Metaphysical, mystical, ethereal. Could it be that Rich is waxing toward the philosophical in his middle age..?

NM

I've never danced on one, but in my time I've kicked around a Vitalink or two... What happens when one implements a virtual bridge within a transparent bridge? Or vice versa?

Sure. While perhaps someone else has said the same thing, I made the realization independently, and use the comparison often in my own classes.

-- Rich Seifert Networks and Communications Consulting 21885 Bear Creek Way (408) 395-5700 Los Gatos, CA 95033 (408) 228-0803 FAX

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How many geeks can dance on a transparent bridge?

Thanks Rich for the history of the concept "transparent bridge".

The contents of your book is very interesting. I will ask if it is available in my school library, and suggest to buy it if not.

I would like to write that in epigraph, on the first page of a training in network introduction. Could I write your name as the author of this trivia?

Regards, Michelot

Ethereal is a network analyzer. ;-)

Two bridging routers configured as half-bridges to form a virtual transparant bridge. Which box does one dance on? Choices, choices...

I actually liked Vitalink TransLAN bridges. It was an interesting concept anyway.