The Office Ethernet
Network Installation
is the Single Most Important Structure
for Implementing Technology
in the Workplace.
At this point, the reader may sigh with
relief and wish to move on. Most companies, after all, have an
Ethernet network of some type, and have had one for many years.
However, in the technology world age comes swiftly. There are
a number of issues that can seriously affect an internal network
structure. This structure is completely vital as a core service
for delivering technology to staff desktops. Networks should
never be taken for granted.
- Has the network been examined
and approved by a network professional?
- Is it a 100Base-TX network at
all?
- How can I tell?
- What about Wireless Networking?
Topics Discussed Include:
Why
100Base-TX? The older
10Base-T speed of 1 to 10 megabits per second remains adequate
for the majority of current office tasks. Still, the technology
world is moving to faster networks and your office should be
prepared to follow. Network-enabled software and shared-process
operating systems are placing increasing demands on even the
fastest networks. As a core element of technology in the office,
support and maintenance of the network structure should be a
high priority.
There are several bottlenecks to full 100Base-TX
speed. Companies which have the correct wiring may not be able
to properly employ this type of network connection. A badly installed
100Base-TX network may have serious performance problems, and
can actually cause system crashes and loss of data.
GX4-
Beyond 100Base-TX: A new network standard, GX4 or "1000Base-T"
is now appearing. This Gigabit Ethernet raises the speed of Ethernet
transfers to almost 1 Gigabit per second. This data stream is
faster than most computers can currently process. Gigabit networking
is ideal for linked server systems. As with 100Base-TX, the first
systems are quite expensive. However, this is a technology to
watch. When installing a new network, ask about the installation's
compatibility with the new GX4 (or 1000Base-T) Gigabit standard.
Major 100Base-TX installation
issues include:
Type
of Hub: The technology
that drives a 100Base-TX network is focused on the network hub
devices, where all the cables eventually connect. Hubs have a
series RJ-45 ports that link individually to each client computer.
The correct type of hub can make a huge difference in network
performance. Issues include Dual Speed hubs, Managed or Unmanaged
hubs, and Switched or regular hubs. The wrong choice of hub for
your network configuration can cause significant problems.
Dual-Speed Hubs: A 100Base-TX network is not a
100Base-TX system unless the hubs are rated for that speed. 100Base-TX
"Dual Speed" hubs can also support the older 10Base-T
standard (100/10). This is an important feature for backward
compatibility.
Managed Hubs: Managed hubs communicate and are
controlled by software so an administrator can examine and modify
network performance either from the local LAN or from a remote
site. For large networks requiring top performance, or networks
that must be supported from the outside, a managed hub should
be seriously considered. However, these hubs are quite expensive.
If you do not have a strong need for this feature, you can avoid
the substantial premium for a managed hub.
Switched Hub: Switched hubs are relatively new
to the scene, but will be the new standard for Ethernet hubs.
A switched hub is intelligent, and only directs a data stream
to a port that requested information. The "regular"
type of hub will send all network traffic to all the ports at
the same time, even if those ports have no need of that information.
Switched hubs can greatly speed up networks. They can even cause
an older 10Base-T network to run at 100Base-TX speeds! This hub
type is best used in an office where all the users can connect
to just one hub (as in a 24-port model), and the network traffic
will go to more than one port on the hub. Another good place
for a high quality switched hub would be for linking servers
together. These hubs can also be used to distribute signals to
other hubs, where each additional hub connects to a central switched
hub. Problems with switched hubs appear when all the traffic
moves toward one port, as with a central server. It is possible
for the switched hub to become "flooded", and to suffer
performance problems. Another problem is when switched hubs are
linked together, and all traffic moving between hubs will pass
on one port. As the performance limitations are overcome (and
this is not a significant issue anymore for the higher-end managed
switched hubs), this type of device will become the standard
hub design.
Wiring
Type: Is the wiring in
your network rated for Category 5? It should say so on the outer
jacket of the cable. If it does not, STOP. Wiring must be Category
5 (or better) rated wiring. Installing new Category 5 wires?
Check to see that it has a Plenum-rated jacket, that will not
give off noxious smoke in a fire. And will this cable work with
the new GX4 standard? Not all cables are created equally, even
between different vendors. Category 5e is the current standard
for network cabling, and should be used for all new installations.
EMI
Problems: Sloppy or unprofessional
installation of network wiring can ruin even the finest cable.
Major installation problems occur with Electromagnetic Interference,
or EMI. The biggest cause of EMI problems is the omnipresent
fluorescent lighting- the ballast unit of these lights produces
enough EMI to scramble the network signal in a cable passing
overhead. All installed cables should be at least one foot away
from the housing of any fluorescent fixture- and no cables should
pass over one, in any circumstance. Motors and cable runs along
electrical conduits are also common sources of EMI.
Wall
Jacks: Merlin and other
popular office phone systems use a telephone-type eight position
RJ-45 wall jack, just like Ethernet cabling. Where a proper Category
5 RJ-45 jack may cost $5 each, these telephone-type jacks can
cost as little as $1 each. Many networks were installed with
excellent Category 5 wiring, but inexpensive jacks. Open a wall
plate and take a look inside. The jack should clearly say "Cat
5", stamped or marked upon it by the manufacturer. If there
are any "screw terminals" (any place where a screwdriver
will be used to attach wires), the jack must be replaced to meet
the Category Five standard. Category Five jacks are always "punch
down" types, normally requiring a 110 punch down tool. Examine
the jack carefully. Category 5 jacks are normally labeled, and
if it meets this standard it should surely say so. ("Cat
5") If these jacks are not Category 5, they will need to
be replaced.
Patch
Panels: All these wires
and cables must meet somewhere, and be connected to the central
network. This connection is made at the Patch Panel. Here, each
cable will be carefully stripped of outer insulation and attached
to either a panel of individual RJ-45 jacks or a device called
a "Punch Block". Common problems include a panel of
RJ-45 jacks that are not rated for Category 5, or older punch
block that is not Category 5 rated. Some systems were sold as
"Category 5" with telephone-type 66 block (flat rectangles
of metal with a hooked slot down the center). This was simply
not true, and 66 block is not acceptable. Any connection system
that does not use either Category 5 rated punch block or RJ-45
jacks will need to be replaced. Again, 110 type connections are
the industry standard.
Quality of Installation: Even with the correct jacks, wiring, and patch
panels, the installation can be rendered useless for Category
5 with improper installation. There are two major problems that
can be encountered- Failure to preserve pair twist, and splices.
Category 5 cable is Category 5 because of the tight twist given
to each pair of wires in the bundle, and a certification process.
This twist is vital, and must be maintained as much as possible
until the wires are connected to a jack or punch block. It does
not take much to damage the signal- No more than 1/2 an inch
of wire, and generally less, should be untwisted before the pairs
are punched down. It is also a good idea to punch each pair of
wires so that they are the Same Length. (This can be difficult
to achieve.) Splices are any joins or repaired breaks in a cable
run. There should simply be NO SPLICES in any Category 5 rated
cables. If damage occurs so that a splice is considered, the
run should be replaced with fresh cable. If a splice needs to
be made (and this should never be done for a proper installation),
we have found that tiny overlaps of cable that are soldered side-by-side
to each other makes the cleanest splice. However, this is tedious,
painstaking, and a violation of the specification. A new installation
should under no circumstances contain a splice.
Patch and Line Cords: The cable that reaches from a wall jack to the
computer must itself be rated for Category 5 use. This is important,
as older cables will cause serious problems if left in place.
The patch cords in the "telephone room" between a patch
panel and a network hub must also be Category 5 rated. Another
big problem is using patch or line cords of an improper length.
Cords that are stretched or suffer frequent pulls will take damage
and fail. Perhaps worse, cords that are too long will often be
neatly coiled- this coil can be a focus for EMI, and will act
like an antenna! An extra long line cord should never be neatly
coiled. Drop it into a chaotic heap instead.
Inefficient
Hubs: Hubs installed
for high-speed networking produced before 1999 may not be as
technically advanced as the hubs available today. Most (unmanaged)
hubs are not all that expensive- if your hubs are over two years
old, seriously consider replacing them with a more advanced product.
Price competition in the network industry forces some companies
to lower the quality of their work to meet a particular price
point. Hubs are a core network function. It is worthwhile to
spend a little more for a good product.
Test
the Installation: The
last, but most important, consideration. How do you KNOW that
your network is installed correctly? The wiring is checked. The
jacks are replaced. You have new line cords, patch panels, and
hubs. But is the network really able to function reliably at
100Base-TX speeds? The answer is- probably. But it is a good
idea to test each individual connection, and confirm that the
network is installed properly. For any new installation, testing
should be mandatory. Most installation vendors will include testing
of each jack and cable run as part of the installation. Ideally,
these test results should be documented in an installation report.
Testing must be done with special Category 5 test devices. These
are usually expensive and sophisticated cable certification instruments,
with special software to record all test results. Adequate results
can also be achieved with a more basic Category 5 "cablemeter"
device. Professional installers should always certify an installation
with one of these tools. Several models of popular Ethernet cards
include network test software that can also be used to test a
cable run.
WIRELESS-
Ethernet without Wires:
Click Here for our full discussion
of 802.11 Wi-Fi Networking.
The 802.11a/b standard for Wireless Ethernet promises to deliver
between 2 megabit per second (low end 802.11b, the current standard)
and 70 megabit per second (enhanced 802.11a) Ethernet connections
without any wiring needed. This technology is starting to find
a popular niche, most especially among home and laptop users.
Normal 100Base-TX networks will run at speeds up to 100megabits
per second, although most users have few issues with the slower
speeds found with 802.11 systems. A wireless system consists
of an Access Point, which will support up to 32(b) or 64(a) users,
and 802.11a or b or both a/b receivers. Currently, many 802.11
receiver cards are often laptop PCMCIA cards. 802.11 has become
a popular built-in feature of new laptops. PCI slot desktop adapters
are also available.
Along with NetGear, SoftProse Technology, Inc. believes
strongly that the future of Wireless Networking (Wi-Fi) is with
a mix of the faster 802.11a and 802.11b systems. Many vendors
already offer cards and access points for dual 802.11a/b use,
and we believe this is the optimal scenario at this time.
There are a number of issues of concern when
installing an 802.11 network. First is encryption. The default
setup for an 802.11 network is to run "open key", without
any encryption. Any user can connect! However, the connections
should be encrypted; WEP security protocal is part of the 802.11
specification in 48, 64, or 128bit strengths. The other issue
is the location of the Access Point- It should be in a central
location as close to the users as possible. Performance of 802.11
networking suffers dramatically as users move away from the access
point.
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