jdc at nterprise.net
Fri May 12 12:02:39 MDT 2000
My apologies for the length...this started as a very short "blurb", but
ended as a book...
I recently found/subscribed to BLUG and had hoped to make it to the
meeting last night, but that's another story...
I've been perusing this month's lug archive and wanted to add a few
RE: Java for Linux...can someone post a synopsis of last night's
discussion? Was there a functional comparison between the different
JDK/JRE's? I've been tasked with investigating the viability of moving
some java apps from Solaris/Sparc to Linux (at least for the development
environment where $5000 machines aren't as much a necessity). Blackdown?
Sun? IBM? Green Threads?
RE: Lexmark 7000 printer driver for GIMP...if it's compatible with the
5700, someone (I forgot who) has added a beta printer driver for the 5700
to Ghostscript5...so if you filter your GIMP output through Ghostscript you
should be able to print on a 7000.
RE: DSL & Viawest...CAVEAT: I am a former employee of Viawest Internet
Services (until April 2000), and was the sysadmin for @denver.net (since
its inception in 1995) which they purchased in September 1999. I left for
a better job, more money, and less stress, and still have quite a few
Brief technical discussion: There are basically 7 prevalent digital
bandwidth technologies for Internet access: ISDN, Frame Relay, point to
point, ADSL, SDSL, cable, and satellite. ISDN (and iDSL) operates most
commonly at 128Kbits/sec, although it is possible (depending upon the
blessing and assistance of your ISP) to multiplex ISDN connections
together for faster bandwidth. However, US West does not price ISDN very
well (they want you to go to *DSL) thus ISDN is really only a viable
option if you can't get DSL in your neighborhood (chiefly if you're too
far away from a digital central office). ADSL is asymmetric...it
transmits in one speed and receives at a different speed. SDSL is
synchronous DSL, transmitting and receiving at the same (usually much
higher than ADSL) rate. Frame Relay is a shared "ring" of
users...functionally similar to a dedicated point-to-point T1 if there are
no other users competing for the bandwidth, but usually with a guaranteed
minimum bandwidth. Point to point is (obviously) expensive, but
guarantees that you are the only user of bandwidth between you and the
With DSL (any flavor) and ISDN there are THREE associated costs:
one is the cost of the router, which varies by manufacturer and capability
(speed, phone ports, NAT/PAT, etc.)
two is the cost of the line itself, which ranges from 19.95/month
(megabit basic DSL) to $70/month (ISDN) or even
higher if you want high-bandwidth SDSL. I've seen T-1
equivalent SDSL from $199/month. Remember, that's just for the
line (which most often also includes your local phone calling
service). The most common provider for ADSL LINE service is
US West, although a very small number of ISP's have equipment
in high-demand US West CO's to "essentially" run a dedicated wire
from your house to their equipment...thus putting your digital signal
on their presumably more reliable "backbone" earlier in the process...
but sometimes the tradeoff is that you don't get local voice calling
on those circuts. Jato and Northpoint are the two predominant
SDSL carriers in Colorado. Both companies have equipment in
many telephone central offices throughout a metropolitan area that
carries the data back to their network...but your ability to purchase
ADSL/SDSL is entirely dependent on whether your chosen carrier
(US West, Jato, Northpoint) has appropriate equipment in the CO
closest to your home/office, and whether your home/office is close
enough to that CO. Thus, you've got to make the call to the
appropriate carrier to find out.
The third cost is the fee paid to an ISP to accept your traffic from your
carrier of choice, put it on the Internet, receive it from the Internet,
and pass it back to your carrier (who then passes the traffic back to your
home/office). US West is both a carrier of ADSL traffic, AND one of the
options as your ISP...and there are separate charges for each service.
You can, however, choose from dozens of other ISP's to receive your ADSL
(and SDSL) traffic. I think Jato and Northpoint both act in an ISP *and*
data carrier capacity, but they usually target higher-end customers.
What separates the wheat from the chaff? In short, it is the bandwidth
capacity of the data carrier divided by the number of customers on that
circuit. There is also similar issue for the ISP...how much bandwidth
divided by how many customers...however if the DSL line carrier has
oversold capacity, then an "open" pipe between the DSL carrier and the ISP
isn't going to improve matters any. Conversely, if the data carrier has
plenty of bandwidth but the ISP's pipe to that carrier is too small...
And don't just assume that because Company X is a data carrier, that their
ISP service will have an adequate pipe!
ADSL has a LOT of subscribers for a very cheap price, and thus the
bandwith/customer ratio is very small...I often heard complaints of "we're
not getting the bandwidth we paid for". No bandwidth is guaranteed for
ADSL from US West!
SDSL is a "premium" service, thus the carriers presume a smaller
bandwidth/customer ratio, provide better customer service, etc. SDSL is
much cheaper than dedicated point-to-point, and cheaper in most cases
compared to frame relay unless you have a multipoint network.
AT&T @home (cable) offers pretty darn fast downloads (up to about
900Kbits/sec in my experience), but limits upstream data to 128Kbits for
$40/month. And, my cable connection has been down three or four times a
month for anywhere from 2-8 hours at a time! Yet I'd reccomend @home
before ADSL unless you need to provide outbound services (mail, web, etc.)
I haven't used @work, but presumably the difference is that they don't
rate limit your outbound data...and charge a heftier price. For serious
use, I'd recommend SDSL or frame...but if you want the most reliability
and can afford it...99% uptime guarantees on a dedicated T1 are the only
game in town (realize that the uptime guarantee is ONLY on the pipe
between you and your ISP (and often on the ISP's pipe(s) to the Internet),
but not necessarily on the pipe between you and some arbitrary point out
there on the Internet).
John-David Childs (JC612) Enterprise Internet Solutions
Systems Administration http://www.nterprise.net
& Network Engineering 8707 E. Florida Ave #814 Denver, CO 80231
Pardon this fortune. Database under reconstruction.
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