below. On Wed, Nov 26, 2014 at 1:49 PM, Noel Chiappa wrote: > > From: Clem Cole > > A few comments on aspects I know something of: > > > > BTW: the Arpanet was not much better at the time > > The people at BBN might disagree with you... :-) > ​Fair enough... ​ > > But seriously, throughout its life, the ARPANET had 'load-dependent > routing', > i.e. paths were adjusted not just in response to links going up or down, > but > depending on load (so that traffic would avoid loaded links). > > The first attempt at this (basically a Destination-Vector algorithm, i.e. > like > RIP but with non-static per-hop costs) didn't work too well, for reasons I > won't get into unless anyone cares. The replacement, the first Link-State > routing algorithm, worked much, much, better; but it still had minor issues > > damping fixed most of those too). > ​You're right of course. I was referring more to the fact that changes tended to be an issue​. I always give Dave Clark credit (what I call "Clark's Observation") for the most powerful part of the replacement for the ARPAnet - aka the idea of a network of network. Dave once quipped: "Why does a change at CMU have to affect MIT?" I've forgotten what we did at CMU at the time, but I remember the MIT folk were not happy about it. > > > > DH11's which were a full "system unit" > > Actually, two; they were double (9-slot, I guess?) backplanes. > ​Right. ​ > > > > The MIT guys did ARP for ChaosNet which quickly migrated down the > street > > to BBN for the 4.1 IP stack. > > Actually, ARP was jointly designed by David Plummer and I for use on both > TCP/IP and CHAOS (which is why it has that whole multi-protocol thing > going); > we added the multi-hardware thing because, well, we'd gone half-way to > making > it totally general by adding multi-protocol support, so why stop there? > Thanks, ​I never knew that. Makes sense. > > As soon as it was done it was used on a variety of IP-speaking MIT machines > that were connected to a 10MBit Ethernet; I don't recall them all, but one > kind was the MIT C Gateway multi-protocol routers. > ​Thought, didn't you guys have the 3Mbit stuff like we did at CMU and UCB first? ​ > > > > Hey it worked just fine at the time. > > For some definition of 'work'! (Memories of wrapping protocol A inside > protocol B, because some intervening router/link didn't support protocol A, > only B...) ​Hey when we did it, we were trying to a UNIX machine to talk to CDC Cyber and an VMS/VAX. No routers. We were happy to just have those systems communicating ;-) I was not smart enough to see something like ARP - which later seemed like such a D'oh moment. Then again -- at the time 48 bits of Ethernet was supposed to me "enough" and you were not going to need anything else. Funny how it all worked out.​ -------------- next part -------------- An HTML attachment was scrubbed... URL: