> On Jun 28, 2023, at 9:56 AM, Jonathan Chapman via cctalk
> <[email protected]> wrote:
>
> ...
>> If you want to link 2 transceivers together on the AUI side then
>> that's a network bridge. Even a basc one is quite a lot of
>> electronics.
>
> DEC's full wirespeed bridge was supposedly considered something of an
> engineering miracle at the time and occupies 2U of rack space!
3U. But yes, it took some pretty good wizardry to run at that speed with the
machinery of the time, certainly at that cost. Along the same lines, designing
the DECbridge-900 was quite an interesting exercise. While it doesn't run
quite at 6 x Ethernet wire speed, it does manage about 60k packets per second.
More importantly, it includes algorithms to ensure that spanning tree packets
are always handled even if the device is presented with an overload. You can
see it in US patent 6,301,224. The DECbridge-900 achieved that performance
with forwarding in software, in a Motorola 68040 at 25 MHz, with a little help
from a 64-entry CAM.
For wiring two 10Mb Ethernet NICs together, a bridge will certainly serve, as
will a pair of transceivers. A repeater will also do the job. Or a DELNI,
which isn't technically a repeater; I don't think it is a device described by
the standard at all, just a piece of magic that interoperates with the standard
by suitable magic.
paul
