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1994-04-05
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TOASTERNETS
An introduction on building your own.
By Tim Pozar
1. - DEFINITION OF TOASTERNET...
Recently with the development of low cost software and
hardware that supports the Internet networking protocols and
the commercialization of the Internet, a level of access for
users and new concept in coopretive networking has been
born.
"Toasternet" is the generic term for Internet-connected
computer networks built very cheaply so as to have a cost
that a small busness, school or individual can afford. In
fact, it has been joking said that these networks are so
cheap, you can connect everything in sight, including your
toaster. Generally speaking, most Toasternets exist to meet
a group's or individual's communications needs, rather than
profit as a motive.
At the same time Toasternets are poping up everywhere with
low cost access to the Internet, there is a push to develop
programs to provide better naviation tools for the Internet
to aid in search and retrival of information. The most
notible tools/programmes are Gopher, WAIS, and World Wide
Web.
2. - WHAT'S BEHIND THE MIRRORS...
The Internet has typically used expensive technology to
transport its packets. Lease lines, microwaves, and fiber
are tradionally costly and require a technical knowlege that
most folks don't have. These "costs" are translated into
high access fees to connect to the Internet.
Recently, with the development of personal computers and
networking hardware and software, the cost and expertise to
install local and wide are networks has dropped dramaticly.
Some of the advances are:
May 21, 1993 1
* Dial-up telephone modems using standards like V.32bis or
V.FAST and compression standards like V.42bis to create
links over low-cost, residential lines have just become
fast enough to run networking protocols like the Internet
Protocol (IP).
* Packet routers can be built out of inexpensive personal
computers running public-domain or shareware software like
KA9Q, PCROUTE, or 386BSD can send IP over these fast
modems from the Internet to computers running client
software for the users.
The hardware and software advances are only half of the
story. A non-profit, or cooprative "agreement" is made
between the members of a Toasternet. The agreement can also
includes the nonexclusive use of the network where, members
can also resell their connections, and the agreement may
also include the non-restriction of data unless existing law
may prohibit it.
With the use of these tools, the availiblity of a close
access point to the Internet (aka. Point Of Presents - POP),
and the cooprative nature of toasternets, the Internet can
be accessed at a very low cost to the user.
3. - HOW INTERNETWORKING IS DONE...
A Toasternet looks just like any other Wide Area Network
(WAN), where leased lines, and/or radio links are used to
connect hubs to other links that eventually connect to each
machine or host in the network. Since a Toasternet is not an
isolated network there needs to be at least one link to the
outside world. This link is a connection to an Internet
provider at the most convenient POP to the network.
We will start looking at the Toasternet layout from the IP
provider's POP going towards the hosts. This is more of a
technical tour through the net and we will cover more of the
politics and social aspects of the Toasternet later.
3.1 - The POP
The POP would normally be a commercial provider. The
provider would require a monthy fee and a startup fee to
install. The startup fee may include the purchase of a
2 May 21, 1993
commercial router ($4,000 to $20,000). The montly fee would
vary with the bandwith that the Toasternet requires. Monthy
fees are typically less than $1000 a month for 56 Kilobit
per second (Kb/s), and upwards to $2000 a month for T1 or
1.544 Megabits per second service.
3.2 - Routers and Links
From the POP the Toasternet starts it's distribution. A
number of technlogies may be mixed and matched to create
data paths to deliver IP to the user.
3.2.1 - The Links
3.2.1.1 - Lease lines (i.e., T1 and 56Kb/s)
There are several leased line options offered by your local
phone company. The lines you would be most likely use for
high speed data links are [FIXME: right nomanclature?] 56K,
T1. 56K linkes will support (as you would imagine) 56
Kilobits per second and T1 will supply 1.544 Megabits per
second. 56K and T1 are used for long distance runs where you
need to get data to the next Central Office (CO) area, LATA,
state or country.
It should be mentioned that there is another high speed link
that most phone companies will offer. It is called T3 and
will provide data at 45 Megabits per second. Normally these
links are pretty expensive, and until a Toasternet gets
several thousand hosts on it's net, T3 would not be
accessable to a Toasternet's pocketbook.
[FIXME: How about fiber?]
Cost of lease lines vary with distance and speed of the
link. Normally the local telephone company will charge for
the distance of the link and for each end termination. An
example breakdown for cost of a 30 mile 56Kb/s link would
be:
(FIXME: get real prices)
May 21, 1993 3
Installation ....................... $1000*
Termination ($100 per end) .......... $200*
Milage ($1/mile after 10 miles) ..... $ 20*
In contrast, a T1 link would run: (FIXME: get real prices)
Installation ....................... $1000*
Termination ($100 per end) .......... $200*
Milage ($2/mile after 10 miles) ..... $ 40*
[*Pacific Bell 5/1/93 for the SF LATA]
These prices may be higher or lower in your area as the
local phone companies' rates vary wildly.
Lease lines are a bit more involved and more expensive to
order than your average residential line. A bit of planning
is involved. For instance, where you install a leased line
needs to be considered at some lenght. You want to design
the link to be the most effective for the speed needed and
the area you need to serve. You also want the link's ends to
be placed at locations were they can stay for some period of
time since each move will cost you another installation fee.
Please see [FIXME: What is the real ref?] 3.2.1.5 for
considerations in choosing the what kind of link you need.
Additional hardware is required for lease lines. Each end of
the leased line is terminated with the equivalent of a
modem. These boxes are called Customer Service Units/Data
Service Units, or CSU/DSUs. Prices for CSU/DSUs will start
around $550 and go up to about [FIXME: get prices from
Dowty] $750.
On the CSU/DSU you will have at least three connections,
power, lease line connection and interface connection. Power
should be simple enough where you just plug it into the
closest power outlet (See [FIXME ref?] 3.x for bullet
proofing your network). The lease line connection will be
tied to the lease line, and the interface will go to the
router.
CSU/DSUs can be ordered with a number of different
interfaces. The most common is V.35. V.35 defines the
[FIXME: Hardware and electrical? Does it include RS-422
too?]
[FIXME: What's happening with RS-232C as an Interface?]
[FIXME: What's happening with async vs. sync as an
Interface?]
4 May 21, 1993
3.2.1.2 - Dial-up phone lines. (i.e., POTS, ISDN, Switched
56)
Unlike lease lines, dial up lines can be temporary links.
The data path needs to be "built", when needed, by dialing
the number of the other end of the link.
3.2.1.2.1 - POTS
"Plain Old Telephone Service/System" or POTS lines are the
voice lines that we commonly used to dial up our relitives,
work, etc. As most of the readers to this essay would
already know, with the addition of a device called a modem,
this POTS line can be used to transfer data over it. At this
point in time, maximum speeds of a POTS circuit is 14.4Kb/s
for the V.32bis standard protocol, and 28.8Kb/s for V.FAST.
Addionally, the compression standard V.42bis for modems can
increase the througput up to four times. It is claimed that
with a V.FAST modem using V.42bis can have a potential
thoughput of 115.2Kb/s. This, by the way, is as fast as the
serial port of a PC using a 16550 UART will do.
There are a number of advantages to POTS lines. The best,
pertaining to your telephone provider, is that they know how
to order it and install hundreds of them a day. This solves
most of the hassles with installation. In my area, Pacific
Bell can take weeks to engineer and
3.2.1.2.2 - Switched 56 and ISDN
These tarrifs are digital dial up phone lines. The POTS
circuit described above is an analog phone line. With POTS
circuits you are transmitting different tones that represent
the digital signalling or the data that is traveling from
one end of the line to to other. Digital circuits vary the
voltage from one level to another that represent digial
signaling.
You do not need a "modem" that converts the data into tones,
but you will need a device much like the leased lines'
CSU/DSU that will "condition" the data for the digital
circuit. They will also handling the signalling needed to
"dial" the other phone you need to connect to. These
devices are called [...FIXME].
Switched 56 has a data throughput of 56Kb/s and ISDN is
May 21, 1993 5
64Kb/s or 128Kb/s depending on if one or both "B" channels
are used. Tariffs for the above will be in the range of $10
to $50 a month, and could include a per minute charge of
around $0.01 a minute. There is some effort by state Public
Utility Commissions and concerned individuals to see that
phone companies offer unmeasured residental rates.
3.2.1.3 - Radio links (i.e., AX.25 via KA9Q or PPP over
high-speed microwave)
Radio's main benifit is that the monthy cost can be
significantly less than leased lines. Unfortunatly, high
speed radio links can be costly to install. A T1 link could
run as high as $30,000 for the link. There is some work by
Amateur radio operators, and advances in spread spectrum
radio that promise very low cost links that could move data
as fast as T1 (1.544Mb/s) and T3 (45Mb/s) speeds.
There are two paradymes for radio, point to point or point
to multipoint. Point to point connections are more like SLIP
or PPP connection where all of the traffic between two or
more networks are going through a radio link and are
terminated by a single router at each end. Normally point to
point connections are used for high-speed backbones that
carry the traffic to each POP.
Point to multipoint links are more like ethernet or tokenet
hardware where all hosts are trying to share the same
resource. In this case, a single frequency or band of
frequencies are used to talk to two or more hosts. These
links are used for hubbing out connections and are more
applicible to POPs feeding the last mile connections to
hosts.
When two or more radio transmitter want to "talk" at the
same time there
Licensing concerns...
Satilite links... Concerns about the 230mS delay
per hop.
6 May 21, 1993
3.2.1.4 - Special Phone Company Supplied Tariffs
3.2.1.4.1 - LADD Circuts
A LADD (FIXME: Local Access D..) is a plain old pair of
copper wires going from a customer's premises (prem) through
a Central Office (CO) back to another customer's prem. This
type of circuit does not have any amplifiers or equalizers
built in and, in phone terms, it is called a "Dry Pair".
Two strong points for LADD circuits are the low cost,
ussually $8/month, and the ability with low cost line
drivers to send data up to 115Kb/s.
3.2.1.4.2 - OPX
3.2.1.5 - Considerations on choosing the right link.
Chossing the right link involves anserwing a number of
questions about how the link will be used.
* Is this a temporary link?
* Can the link go up and down as demand warrants?
* If it is a temporary link, can the user(s) of the link be
happy with the speed of a dialup SLIP or PPP link? With
V.32bis/V.42bis modems, the speed would be around 21Kb/s.
ISDN links would be 64Kb/s or 128Kb/s depending on how
many B channels used.
* Are both ends of the link within line-of-sight of each
other? Can one site see the roof of the other site?
* Is the end of the link feeding many high demand users?
May 21, 1993 7
3.2.2 - Routers
At each branch of the links, routers are used to route the
data down the proper path. Typical routers are:
* Commercial (CISCO, 3com, Livingston)
* Shareware/Public Domain (KA9Q, PCROUTE, 386BSD)
4. - CASE STUDIES...
4.1 - TLG
(ONE PARAGRAPH) topology (20 words)
constituency (WE'RE SO SOCIALLY RESPONSIBLE WE CANT
STAND IT) history how it started
4.2 - RAINnet
(TWO PARAGRAPHS) topology (20 words)
constituency (WERE SO RIGHTEOUS WE CANT STAND IT
EITHER) Randy brags here (yes Randy) history
how it started
IP suppliers: how they came to exist our
troubles with (in context)
-- CONCLUSION What we are doing now. (ONE PARAGRAPH) Where
we're headed.
With the combination of the development of Toasternets and
better navigation tools the Internet ....
8 May 21, 1993
CONTENTS
1. - DEFINITION OF TOASTERNET........................... 1
2. - WHAT'S BEHIND THE MIRRORS.......................... 1
3. - HOW INTERNETWORKING IS DONE........................ 2
3.1 - The POP....................................... 2
3.2 - Routers and Links............................. 3
3.2.1 - The Links 3
3.2.1.1 - Lease lines (i.e., T1 and
56Kb/s) 3
3.2.1.2 - Dial-up phone lines. (i.e.,
POTS, ISDN, Switched 56) 5
3.2.1.3 - Radio links (i.e., AX.25 via
KA9Q or PPP over high-speed
microwave) 6
3.2.1.4 - Special Phone Company
Supplied Tariffs 7
3.2.1.5 - Considerations on choosing
the right link. 7
3.2.2 - Routers 8
4. - CASE STUDIES....................................... 8
4.1 - TLG........................................... 8
4.2 - RAINnet....................................... 8
- i -
