hardware_network

This is part of The Pile, a partial archive of some open source mailing lists and newsgroups.



Subject: Re: Dial-in-Server
From: Ramon Gandia <rfg@nook.net>
Date: Tue, 29 Jun 1999 11:14:34 -0800


redhat-list@mb.actech.net wrote:
> 
> On Tue, 29 Jun 1999, Stephen Lavelle wrote:
> 
> > My company has just acquired a new site which is about 2 kilometers from our
> > present location. At the present site i have a linux box (Red Hat 2.0.36
> > Kernel) which provides file sharing for windows users on the lan (with
> > Samba). The linux box also masqs for the windows users on the network (in
> > the private 198.168.*.* ip series numbers) to provide www and email
> > services.
> > When the new site is up and running i would like to provide file sharing
> > for the remote windows machines on our linux server so that both sites can
> > share databases etc.
> >     If anyone has any suggestions about how to implement this in an effective
> > and cost effective way (dial in, direct cable etc) I'd be grateful
> > Regards,
> > Stephen
> >
> 
>    You can do radio at 2 megs per sec at a cost about $5K.  And 10 Megs
> about $11K.  Laser is also an option if line of site.

Young Design makes a 2 mbps radio link, web based interface
for easy admin and ethernet connection (bridge).  http://www.ydi.com
Prices are about $1300 per end; with larger antennas and
amplifiers they will go 30-40 miles, in your case the standard
stuff should suffice.

If you prefer wireline, you can get 768K over a single wire
pair and 1.544 over a two pair line.  Many phone companies
will charge you T1 pricing for the two pair line.  In Nome
that comes out to about $600 per month.  The single pair is
not considered a data line, so the cost is $50 per month.
Big difference.

The lines need to be "unconditioned copper"; ie, they are
NOT T1 lines, just two plain wires end to end.  Bridge taps
do not bother it.  The equipment is made by Pair Gain, and
comes in the Megabit Modem 768 (single pair, and you need
the master and slave called the 768 Plus and the 768).  It
works out of the box with ethernet interface.  The second
type is called the Campus.  You can get different interfaces
for it: ethernet (Campus Rex), V35 sync, V35 Fractional sync,
and DSX-1.  They claim that you can have different interfaces
at each end, but I have not found that to be the case.

Pricing on the Megabit Modem is about $1100 Plus, and 900 for
the 768, or about $2K or a bit less for the pair of required
units.  They are totally transparent to operation of an ethernet
link.  You plug them into your hub at this end, and the other
end into its hub and you have a link between the two.  The
distance supported is about 3-5 miles over unconditioned copper.
http://www.pairgain.com   I use these quite a bit over here,
and they are totally solid performers.

===

From: Jason Costomiris <jcostom@jasons.org>
Date: Thu, 22 Apr 1999 21:03:24 -0400
Subject: Re: <OT> router feasibility?


On Wed, Apr 21, 1999 at 08:34:12PM -0400, p wrote:
: I was thinking of taking a Pentium class computer and installing a
: couple quad port ethernet/fast ethernet card, and maybe a couple ATM
: nic's if I can acquire some drivers..  I was then going to use this
: machine as a router.  Before I even try this I was hoping to run it by
: the venerable experts here:)

There are some things that Linux is great at, and there are
things it's just ok at.  Being a router is not Linux's
strong suit.  You need to move that kind of bandwidth?  Get
a real router, or better yet, a nice L3 switch, like a
Catalyst 550x.

: 1. Which is the most appropriate distro?(Stampede, Redhat? LRP? or would
: FreeBSD or Solaris or whatever be better?)

Not Solaris.  FreeBSD, or whatever Linux distribution you
like, only using a 2.2 kernel.  The LRP is okay as long as
you're not going to swamp the poor defenseless PeeCee
hardware :-), and don't need a totally reliable router. [1]

: 2. What kind of machine would I need to do this?  Would a pentium 133
: w/32meg ram suffice?

Not even close.  You'll swamp the backplane.

: 3. What is the best qual-port ethernet card?(best meaning most stable
: driver)

The Matrox Shark (tulip based) is a great card.  Nokia uses
those as the quad fe's in their FreeBSD based firewalls.
Great cards.  They run around $1k a piece.

: 4. Can the hardware handle a sustained 50% utilization on all of these
: interfaces?  Would a system like this be flooding the PCI bus?  What
: would happen if the PCI bus gets flooded?

I doubt the box could handle 50%, full duplex, even half duplex on all
8 fast ethernets, and a pair of ATM nics.  Let's look at the math:

8 FE's running full duplex is 800 Mbps of bandwidth (at
50%).  2 ATM NICs running full duplex is 310 Mbps.  That's
over 1100 Mbps.  That's more than the PCI bus will handle,
IIRC.  You're also not accounting for traffic bursts.

: 5. Can linux handle a sustained 50% utilization on all of these
: interfaces?

Since the hardware doesn't have the guts, it's kind of
irrelevant, eh? :-)

: 6. What else am I missing?

A Cat 5505, Supervisor III, RSM, some ethernet ports and a couple of 
ATM ports.. :-)

[1] Routers should not have floppy drives or hard drives.
Boot from solid state, like flash, and then run from RAM is
what you need.  Also, Linux isn't specifically tuned to
perform routing functions, like IOS is.

===


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