[rescue] SBUS Efficient Networks Inc fiber network adapter on a Sparcstation 4

[Kenneth Seefried]

> Some years ago I bought a Sparcstation 4 that came with a Efficient
Networks Inc ENI-155s-MF SBUS fiber network card. I wonder how this machine
was used, probably as a server to justify the cost of a fiber adapter...

Hey...I can use all those months of Cisco, Newbridge and Fore Systems ATM
training I took in the 90s.  If I can remember it.

I kinda doubt it was a server; a SS4 would be a bit underpowered running
ATM 155; maybe ATM 25 wouldn't be too bad. Certainly the server tier we
deployed were significantly beefier.  And there were use cases (e.g traffic
prioritization esp for real time and multimedia transport) where maybe
(maybe) ATM was worth the cost and overhead.  And pain.

One thing I did see a good bit of in ATM networks was one or more smallish
workstation class machines acting as a LECS (LAN Emulation Control Server),
LES (LAN Emulation Server) and/or BUS (Broadcast and Unknown Server), often
the same server and collectively called LAN Emulation (LANE) servers.
*Vastly* oversimplifying and incomplete: since ATM is not much like
Ethernet/TR/FDDI (all PtP/VCs, no broadcasts, etc.), if you want to run
something that looks like IP over it you needed to be able to map things
like broadcasts, multicasts, network membership, etc. to ATM native tech.
Particularly early on, some vendors deployed products (e.g. Cisco
Lightstream) that separated out LANE functions from switching and put it on
a separate COTS box, and every client in the ATM network would chat away
with them to pretend they were on a LAN.

So, I'd guess your machine was one of 3 things:

1) An endpoint (called a LAN Emulation Client or LEC in ATM-speak).
2) It was a LANE server of some mix.  You'd be able to tell from looking at
the installed software and the doco should still be out there on the net.
3) Technically, it could be a pure ATM endpoint with no LANE, but I never
saw any of those outside of a telco network.

ATM is one of the very few network technologies I *never* say "I should
pull together the parts to build a network to play with".

Side note: There was a 622Mbps SBus ATM card.  Sun said it would run in a
SS2.  No, really.  I never tried that as our experience was that it would
bring a SS690 to its knees under load and even the SS2000 showed excessive
load.  ATM didn't last long in the Sun world.  HP never was big on it.
IBM, of course, held onto it for much longer.

KJ
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