OT: old Ciscos, was Re: [HECnet] Ethernet Marks 40 Years Linking People, Computers in a Wired World

[Dave McGuire]

On 05/24/2013 08:58 AM, Clem Cole wrote:
I fear a sad part of this slide show is that many of us remember and were
part of it all.     Some of us   programmed these machines (I admit that I still
have some of these pieces in my basement).   I was disappointed they did not
show a "stinger tap." The picture of the Alto shows the first mouse     the
Hawley Labs mechanical mouse (which I miss for its feel).     Check out the
picture of the first Cisco router using Intel Multibus (with a Motorola 68k
in it) looking so awkward.

  That's a Cisco AGS or AGS+.   I've deployed a bunch of those, and ran one
for my home T1 for a long time (back when that was a lot of bandwidth!), and
I still have one here, but it's about to get shipped out to Josh Dersch in
Washington as part of a swap deal.   But I still have an MGS and a CGS, which
are the same thing but smaller chassis with fewer slots.

  Multibus, yes...but that's not the worst of it!   Some here are no doubt
familiar with NuBus, which is generally known as the expansion slot bus of
the Apple Macintosh II.   It's not an Apple bus, however!   I don't recall
where it hails from, but it's a general purpose bus, and a pretty nice one at
that.

  Anyway, the difference between the AGS and the AGS+ is that the AGS+ card
cage has a second backplane, with DIN-style triple-row connectors, where the
Multibus P2 card-edge connectors would normally go.   That's the Cbus, a
32-bit-wide bus operating at something like 16MHz, quite a bit faster than
the Multibus interconnect.   A Cbus Controller card was plugged in, which
acted as a bridge between Multibus and Cbus.   The Cbus Controller had a bit
of very fast packet memory, and a purpose-built microcoded processor to
handle communications.   Packet memory was slotted dynamically at
configuration time, divided up by the MTU settings on the attached
interfaces.   It was a very nice system; highly capable and very flexible.

  Peter will correct me if I'm wrong here, but the word on the street was
that when the new "flagship" Cisco 7000 was introduced, its routing
performance was lackluster compared to a well-configured AGS+, which caused
some issues with 7000 adoption.   Later 7000-family hardware enhancements
corrected those performance issues.

  To drag this kicking and screaming to on-topicness...I'm sure someone here
can tell the story of where ciscoSystems came from, more or less as a cash
cow that eventually resulted in the founding of XKL.

                        -Dave

-- 
Dave McGuire, AK4HZ
New Kensington, PA