Date: Sat, 9 Dec 1995 13:35:19 -0800 (PST) From: Tom Samplonius <tom@uniserve.com> To: Joe Greco <jgreco@brasil.moneng.mei.com> Cc: winter@jurai.net, sreid@edmbbs.iceonline.com, freebsd-isp@freebsd.org Subject: Re: Hardware for ISP / WWW server Message-ID: <Pine.BSF.3.91.951209131530.21094A-100000@haven.uniserve.com> In-Reply-To: <199512092006.OAA22400@brasil.moneng.mei.com>
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On Sat, 9 Dec 1995, Joe Greco wrote: > > On Sat, 9 Dec 1995, Joe Greco wrote: > > > > > > > 28.8 kbps modems for dial-up > > > > > > > > Run dialup from a terminal server. A Livingston portmaster is a great > > > > box and has a very hackable security server. (Um... no, rather its easy > > > > to modify to suit your needs) > > > > > > Ewww, no way. > > > > > > A Livingston Portmaster has some pretty gnarly drawbacks: > > > > > > 1) has problems with subnets > > > > None, that I've seen. And I run quite a few sub-nets from various > > Portmasters. In fact, my house is connected by one. > > Tried running one on a non-class-C subnet? Yep. I've routed multiple 255.255.255.240 subnets, as well as had a Pormaster on a 255.255.255.128 subnet. > > > 2) requires you to waste IP addresses due to the way the thing reserves > > > addresses for dropped connections > > > > Huh? You need 30 addresses for 30 ports. There was a reported bug, > > that said that the unit would sometimes use 31 or 32. But still hardly a > > waste. > > Not a bug, a feature. The Portmaster reportedly will try to "hold on" to a > connection pending a reconnect, but on a busy dial in pool you need to > reserve more like 40 addresses minimally. Doesn't happen. On a busy pool, it will just re-use what's available. > > > 3) in the case of dropped connections totally bungles the way its handled > > > > I haven't seen this either. > > This is directly related to 2)... I recently tracked a bunch of hanging > processes out at Exec-PC to this very problem. The Portmasters do something > strange (not quite sure what since I didn't have a network sniffer) that > appears to make FreeBSD's TCP/IP think that the connection is still out > there somewhere... and they have had other problems with this "feature" as > well. I've never seen this before. What kind of hanging processes were they? ... > > > If you want a "real" terminal server, buy an Annex. > > > > A Portmaster can run all ports with PPP at 115,200 baud continous. Try > > that on an Annex. > > Guess it depends which Annex.. > > > > If you want a more flexible solution than either of these two, go get a > > > dedicated FreeBSD box. With the price of a 486DX4/120 motherboard being > > > around $200, 16MB of RAM for about $500, and a 16 port BocaBoard for about > > > $250, you can make a really reasonable terminal server quite easily. > > > > The problem is, is that PC serial hardware will never give you > > performance of a terminal server. > > I would think that you could get pretty decent performance out of a high end > 486, which are dirt cheap. Or perhaps a Specialix card, if need be... and > to be quite honest, I've never seen an ISP where all ports are running PPP > at 115,200 baud continuous. I'm often out at Exec-PC, and they're a large > Portmaster shop (13? portmasters on the 390 lines in their Milwaukee POP). > Most of their lines are connected whenever I look, yet I only see bits of > bursty data here and there. The need for a terminal server to run 115200 > on all ports simultaneously is marketing bullshit. With 28.8K modems and > most graphics being fairly compressed, I would be suprised if the average > CPS on a maxxed out port exceeded 4000cps, and at maybe 20% duty cycle under > "heavy" traffic conditions, for 16 ports that's 13Ktotal/sec or for 32 ports > that's 25Ktotal/sec, which is roughly what I have observed sio to be capable > of on a 386DX/40 (two 230.4K serial ports, 1 in use at 22K/sec, 1 in use > with a 28.8K modem at around 3K/sec). > You are right, 28.8k modems do not require continous 115,200. However, some terminal servers can't handle all ports at 28.8k. What is enough for a "typical" terminal server? I'd prefer that the unit have lots of extra horsepower that you'd never use, rather than it bog down once in a while. As well, Portmaster have faster response time. When I used a PM at home for a dedicated 28.8k line, ping times were consistently faster than my FreeBSD box. > And of course with FreeBSD you can go down to the corner store for spare > parts, and you get the source. What more could you ask for? I've never needed to replace anything in a Portmaster. Tom
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