SHARED BROADBAND ANNOYANCES
OUTGROWING YOUR ROUTER?
Our Ethernet network shares a DSL connection
with a router. The router has four ports, but now we're adding a
fifth computer to the network. Do we have to buy another
When it comes to routers, it's one to a
customerone router plugged into one DSL modem. Your solution lies
in a hub or a switch, which connects computers together. The hub or
switch, having collected the connections of multiple computers, can
be connected to the router. To connect the hub/switch to
the router, use one of the ports you're currently using for a
computer. Plug the computer you're removing from the router into
the hub/switch. In fact, you could connect all the computers to the
hub/switch. (See Chapter 1 to learn the differences between hubs
WIRELESS ROUTER IN A WIRED
My husband won a door prizea wireless router. We
have a wired network (two computers and a hub), and we share a
telephone modem. It's annoying to think we have this free device
that would let us switch to a cable modem for Internet access, and
we can't use it unless we buy the equipment to change our network
Hold it! You don't have to change a thing. Wow,
for the most expensive device on the network. Good job!
You can use a wireless router without moving your network topology
to wireless communication because all routers, wireless or wired,
have Ethernet ports.
Take a peek at the back of the router. You
should see one port labeled WAN, and that's the port you use to
connect to the cable modem (WAN stands for wide area network, and
it's a reference to the Internet). Then look for one or more ports
labeled LAN. Those are the ports you use to connect your computers
to the router (LAN stands for local area network).
If you find one LAN port, run Ethernet cable
between that port and your existing hub. Read the documentation
that came with the hub and the router to see which port on the hub
you should use for the connection (usually, it's the hub's Uplink
If you find two LAN ports, plug your two
computers into those ports and sell the hub (or save it for the day
when you expand your network with more computers).
CABLE MODEM SPEED VARIATIONS
We have cable access and we've noticed that
during the early evening, when the whole family is usually on the
network, our transmission speed is markedly slower. A friend told
me that it's because the network is crowded with users sharing
bandwidth. It's annoying that four people accessing the Internet
could cause this
. It's also annoying to
money each month to get speeds that don't seem much faster than our
previous telephone modem provided.
Your friend is correct, but he is rather
imprecise. The network referred to is the cable access provider's
network, not your home network. Cable access works more or less
like your network, with a number of computers attached to a single
network. The network "hub" (I'm using the
at your cable company's
(CMTS), the jargon for which is the
. The head end has a
certain amount of bandwidth, which is divided among the current
Most cable companies have plenty of bandwidth,
and although you might notice a slower speed when the
of school and the parents are home from work all over the
neighborhood, it should never be as slow as your telephone modem.
If it is, call tech support.
To test your broadband speed,
check out CNET's Bandwidth Meter at
CABLE ACCESS UPLOAD AND DOWNLOAD SPEED
My cable company provides high-speed download
capacity, but the upload speed is a fraction of the download speed.
For this monthly fee, why don't I get equal speed?
The upload speed is always much slower than the
download speed for several reasons. The slower upload speed lets
the cable company save some bandwidth, which keeps the system
robust when lots of users are online. Also, this is a way for cable
companies to discourage users from running big, busy servers (such
as a business would run) for the price of residential service. In
truth, you don't really need a lot of upload speed unless you're
running an Internet site from your home, or you use your computer
Incidentally, when data is sent at a slower
speed, data loss is usually less, and the cable system can manage
any problem with signal quality. When data loss occurs at high
speed, many data packets have to be sent again, which effectively
the speed of the data transfer. As a result, your download
what it's advertised to be, but the upload
speed is usually right on target.
Some cable companies now offer "business
packages" in which the upload speed is slightly higher than the
normal residential upload speed. These packages are not designed to
let you run business web servers, but they can be useful for
workers who telecommute and upload a significant amount of data. If
upload speeds are important to you, switch to DSL.
UNCAP CABLE MODEM SPEED
about a way to pay for one speed, and
then change the way the cable modem operates to get the real
maximum-possible speed. It's called uncapping, and it's annoying
that it's apparently a secret known only to computer
Information on uncapping is available all over
the Internet, and
, many of the web sites that
describe it (or offer software to uncap your cable modem) don't
explain the important features:
It's illegal, and cable companies have
prosecuted people who try uncapping.
It's really close to
to do with
today's cable modems.
If you manage to uncap your modem, your cable
company will discover your trick quite quickly, and then you're in
Many of the software
downloads offering uncapping features are really viruses.
If you've never
heard of uncapping, see the sidebar
"Uncapping Cable Modems:
An Urban Myth in the Making."
The technology behind the
uncapping function exists only for cable Internet access; DSL
on a totally different technology that can't be
Cable data transmissions can be blazing fast,
but all cable companies cap the transmission speed to make sure
multiple users get a fair share of the bandwidth. The cap is
imposed on the modem, not the wires. Today's cable modems operate
under a technology called
(Data Over Cable Service Interface Specification) to manage the
modem's behavior. DOCSIS controls the way the modem communicates
with the cable company's head end. When the modem checks in, the
head end matches the modem's MAC address (a unique number assigned
to the modem during manufacturing) against the specifications for
this connection (the package you purchased). The head end downloads
a configuration file to the modem. The file contains the IP
address, the settings for the speed cap, and other communications
instructions. The cable modem begins communicating once it receives
the configuration file.
You can't stop this process, so you can't uncap
the speed. Some people think that if they can learn the MAC address
of a modem
to a customer who's allowed to transmit at
higher speeds, they can use known technology to change the MAC
address of their modem to get a different configuration file from
the head end (one with a higher-speed cap). This doesn't work
because the head end won't let two MAC addresses on the network at
the same time, just the way your home network won't let two
computers with the same IP address participate on the network.
BUY YOUR OWN CABLE MODEM AND SAVE
My cable company will either rent or sell me a
modem. Is it possible to buy a cable modem from a source other than
the cable company?
Yes, you can now buy cable modems, so you're no
longer locked in to your cable company's rates. A few
the cable companies had a monopoly and forced you to either buy or
rent a modem from them. Today, Linksys, Netgear, D-Link, and other
manufacturers all offer cable modems.
Make sure the cable modem
you purchase is DOCSIS compliant.
ENHANCE YOUR DSL SPEED
I have residential DSL service, but it seems a
little slow. How can I increase the speed of my DSL modem?
There are two ways to get faster DSL
The maximum speed available for DSL services
depends on your location relative to the telephone company's CO.
The further away you are, the lower the maximum attainable speed.
When you sign up for DSL services, the telephone company
the maximum speed available for your house. If you live too far
from a CO, you can't get DSL service for any price.
A wide range of DSL technologies is available
today, although some are specific to certain providers and some are
available only in certain
. However, a few are common
enough to be available through any of the DSL service providers who
serve your neighborhood. Your distance from the telephone company's
CO can affect the maximum speeds mentioned here.
(Asymmetric Digital Subscriber Line) is the common form of DSL for
residential subscribers. The signal is asymmetric because most of
the bandwidth is devoted to the downstream direction. A small
portion of bandwidth is available for upstream communication. ADSL
offers speeds up to 6.1 Mbps for downloading and up to
640 Kbps for uploading. When you subscribe to ADSL, the telephone
your phone line to separate the DSL data signals
from your regular telephone services (telephone, fax, and telephone
(sometimes called GLite, splitterless ADSL, or Universal ADSL) is a
way to provide ADSL without sending a technician to split the line
end (the split is at the telephone company's CO). DSL
Lite provides speeds up to 6 Mbps downstream and up to 384 Kbps
upstream (slightly slower than ADSL, but very few people notice the
DSL) offers speeds up to 1.544 Mbps (higher in Europe) in both
directions (that's why it's called symmetric). SDSL doesn't use an
existing telephone line split for DSL services. Instead, the
telephone company runs a line
for the service. Many
DSL providers call this "Business DSL." The service usually
includes a number of fixed IP addresses.
Usually, you need filters only if you installed
your DSL equipment yourself. More and more DSL providers offer a
self-install option, and to make self-installation more attractive,
they charge you for a professional installation. They send you the
modem, a piece of Ethernet cable, and some filters.
The big difference between a self-install and a
professional install isn't the way the equipment is installed and
connected (a modem connection to a computer, or to a router, is the
same no matter who does it); it's in the way the telephone line is
When the telephone company sends a professional
installer to your house, the telephone line is split just as it
enters your house (usually at the gizmo attached to your house by
the telephone company, which is called a
Network Interface Device Box
). The wires
carrying the DSL frequencies are directly attached to the phone
jack you're using for your modem; in fact, most of the time the
installer adds a new phone jack just for this purpose. That jack is
delivering pure DSL frequencies, and because you never use it for
telephone services, you won't have a problem.
When you install your own DSL equipment, no
telephone company personnel come to your house. Your telephone line
is split back at the telephone company's office, and the DSL
frequencies are connected to your DSL port at the phone company.
This means the lines coming into your house are ready for (and are
delivering) both DSL and telephone services. It doesn't matter what
telephone jack you use for your DSL modem, and because it doesn't
matter, you might have a problem. Hence, the need for filters.
The general rule of thumb is that you must live
within 18,000 feet (about 3.5 miles) of the CO. However, other
factors can extend this distance. If your phone company uses
24-gauge wire instead of the older 26-gauge wire, the data signal
can be carried a couple hundred feet further. If your phone company
cable (not a common scenario), you gain several
hundred feet more.
DSL services are priced by speed. If you live
close enough to the CO to have plenty of choices, your maximum
speed is a matter of how much you're willing to pay each month.
DSL UPLOAD AND DOWNLOAD SPEED
My DSL service has a pretty fast download speed,
but a much slower upload speed. I maintain web sites and need to
increase the upload speed.
You can buy DSL services with high upload
speeds, as long as you're willing to pay the priceand it can be a
rather hefty price. You might have to change the type of DSL
service you subscribe to, and that, in turn, can change the way
your telephone lines are used (see the sidebar "Overview of DSL
Unlike users of cable services,
DSL users don't
for bandwidth with their neighbors. Each
DSL line is independent, which makes it easier to custom-design
your upload and download speeds.
DSL LINE FILTERS
I was told that the DSL signal uses a totally
different part of my telephone line than my telephone. However, my
DSL provider said I had to put a filter on every telephone jack in
the house. Why don't they warn you that DSL messes up your
You have it backward. Your DSL provider isn't
using filters to protect your phone lines from DSL interference;
the filters protect the DSL frequencies from telephone frequency
interference. Telephone equipment is always "listening in" on the
phone line, so the telephone knows when to ring and the fax machine
when to pick up. The
isn't "high tech," and can cause a short circuit in the DSL signal
and interfere with data communication.
The filters provide a way to stop the telephone
frequency from moving into the DSL frequenciesfrequencies it has no
business occupying (see Figure 6-6). Plug one end of the filter
into the phone jack, and plug your telephone or fax machine into
the RJ11 connector (which should have a marking, such as the word
"phone" or an icon that looks like a telephone).
Figure 6-6. Filters protect your DSL
signal from your telephone signal.
If you have more than one
telephone line coming into your house, you have to filter only the
that serve the line your DSL uses.
DSL AND HOME SECURITY SYSTEMS
Our home security system dials out when security
is compromised. It uses the same telephone line as our DSL modem
and telephones because we have only one line. After experiencing
all kinds of trouble with our DSL Internet access, we learned that
the security system is interfering with the DSL frequencies. We're
told we have to bring in a second telephone line and use it for
either the security system or the DSL service.
If your DSL system was professionally
installedand your line was split at your house and the DSL
frequencies were delivered to the telephone jack for your modem.
Unfortunately, DSL providers usually ignore this whole subject, and
about security systems when you're asked if you want
to self-install your system. If you have a security system, tell
your DSL provider you need a professional installation.
BUYING DSL SERVICE FROM THIRD-PARTY
My local telephone company offers DSL services,
but I'm really not a fan of their service and response time for my
telephone service. Can I buy DSL services from somebody else?
Yes, unlike cable companies that usually have
exclusive franchises for an area, the services available over
telephone lines are
to competition. DSL services are included
in that paradigm. Before you get excited, remember that no matter
who provides your DSL service, they have to use your telephone
company's lines. So, in a way, you're still locked into your local
I use a third party DSL provider for my
broadband connection, and I've been happy with the service. My DSL
provider (Speakeasy.net) actually subcontracts the technical side
to another company (COVAD). When I have a problem, I call Speakeasy
and they immediately begin diagnostic procedures while I'm on the
telephone with the support person. They check the modem, and the
configuration back at the CO. (COVAD has a
in the phone
company's CO.) If the problem is with the phone line (the most
common scenario), COVAD notifies my local phone company (perhaps
they just yell down the hall), so I don't have to make that call
(which is always a frustrating experience). The phone company makes
of COVAD, and that seems to hasten the
telephone company response time. At one time I thought I might be
the improved service the telephone company provides for
my DSL services, but my neighbor who gets her DSL directly from the
telephone company invariably has longer outages and more
frustrating support experiences than I do. Oh yeah, my monthly cost
is the same as my neighbor's, (the telephone company customer).
ROUTERS ARE NOT SPECIFIC TO MODEM
I went to a local store to buy a router to share
our DSL connection. How can you tell whether the router is for a
DSL modem or a cable modem? Is there some technical code in the
model number that I don't know about?
Routers talk to both DSL and cable modems
because the router's technical job is unrelated to the type of
broadband communication your modem provides. Your modem connects
your home network to your broadband provider, which in turn sends
your communications on to the Internet. Your router's job is to
merge the multiple
of your network (your computers) so
that they can address the modem. The router just delivers the data;
the data signal into the proper technology for
your broadband provider.
ROUTERS AND FIREWALLS
Our network shares a DSL connection with a
router. The router doesn't have a built-in firewall, and I'm not
sure how to protect the network.
If your router doesn't have a firewall, you must
run a firewall on every computer on the network. The router sits
between your network and the Internet, and if an Internet intruder
can get past the router (which he can if the router isn't protected
with a firewall), he can get to every computer connected to the
router (even if the computers are connected to a hub or a switch,
which in turn are connected to the router). Look at Zone Labs'
ZoneAlarm firewall, which you can download for free at
WIRELESS ACCESS TO A WIRED ROUTER
We have a wired network and share our broadband
connection with a wired router. My laptop from work has a wireless
network adapter. How do I join this computer to the network so that
I can get to the Internet?
You have two choices for mixing a wireless
computer with a wired network:
is a device that connects to both wireless and wired devices. It
has an antenna (to communicate with wireless devices) and an
Ethernet port. Use an Ethernet cable to connect the access point to
your wired router.
DEVICES TO A ROUTER
Our home network is growing into a mix-and-match
configuration. The original network, two computers and a router, is
located on the second floor. On the first floor, we want to network
two computers using either phoneline or powerline connections so
that we don't have to run Ethernet cable to the first floor. How do
we get the first-floor computers on to the Internet?
You need a
, which is a device that connects to
both an Ethernet device (your router) and a phoneline or powerline
device. Locate the bridge on the second floor, near the router. Use
an Ethernet cable to connect the bridge to the router. Then, plug
the bridge into the appropriate connector (a phone jack for a
phoneline network or a wall plug for a powerline network). All
manufacturers of networking equipment sell bridges.