No one likes to get the dreaded "something failed" phone call in the
middle of the night. While most well designed and properly installed
Ethernet networks rarely experience catastrophic failures, performance
can slowly degrade and then the network slows dramatically. A survey of
400 large companies by PC Week indicated that the average cost
of having a network unavailable for less than one percent, equating to
about 87 hours per year, is more than $7 million annually.
As the number of users on the network grows, so should the server.
Size matters and it is important to consider upgrading servers to units
featuring faster CPU speeds, multiple CPUs, larger backplane capacity,
more memory and larger power supplies. Redundant arrays of independent
disk drive (RAID), which read and write data from multiple drives
simultaneously, are commonly used for networks. These drives may be
housed within the same cabinet as the CPU or as external systems.
Figure 1. Network reliability compared to time
lost and costs incurred.
Storage area networks (SAN) are not connected directly to the server
backplane, but rather as independent network devices connected to the
server through a separate high-performance network segment using
protocols such as Fibre Channel, resulting in increased performance,
but at a relatively high price.
Consider increasing the throughput of your network from 10Mb/s to
100Mb/s or perhaps to 1Gb/s. With the availability of low-cost network
interface cards, routers and switches, it is easy to improve the speed
of a network simply by replacing older and slower devices with current
Consider the type of cabling used to interconnect the devices. Even
CAT5 cabling is not sufficient to support the current generation of
through puts greater than 1Gb/s. In fact, upgrading the equipment
without replacing older cabling may cause the network to perform
Perhaps the most likely point of failure of a network lays within
its connection to the Internet. Several methods can be used to connect
local networks to the Internet, including DS3, DS1 (or fractional DS1)
and DSL to name a few. To reduce costs, most companies purchase the
minimum bandwidth to support a particular facility. Often, network
administrators fail to increase the bandwidth of the connection to the
Internet. The effect of having too little bandwidth for too many users
is obvious, however, another less obvious problem is congestion that is
created over the Ethernet segment while traffic is buffering to the
Internet connection, basically slowing the entire network.
Protecting your network from external, and in some cases internal,
threats will reduce the chances of data loss or infrastructure damage
by hostile users and hackers. Vi-ruses are particularly damaging and
can cause the performance of your network to decrease, or in many cases
cease operating. The National Infrastructure Protection Center (NIPC),
the recently-created arm of the FBI charged with assessing,
investigating and responding to threats to our national network
infrastructure, recommends these tips for small business and home
computer users, but these apply to businesses of any size:
Use strong passwords. Choose passwords that are difficult or
impossible to guess. Give different passwords to all accounts.
Regularly backup critical data. Backups must be made at least
once each day. Larger organizations should perform a full backup weekly
with incremental backups every day. The backup media should be verified
at least once a month.
Use virus protection software. That means three things:
having it on your computer in the first place, checking daily for new
virus signature updates and then actually scanning all the files on
your computer periodically.
Use a firewall. Firewalls are usually software products. They
are essential for those who keep their computers online through the
popular DSL and cable modem connections, but they are also valuable for
those who still dial in.
Do not keep computers online when not in use. Shut them off or
physically disconnect them from Internet connection.
Regularly download security patches. The NIPC publishes
timely information related to potential security threats, as well as
suggestions about securing your network from potential attackers. Visit
its website at www.nipc.gov.