u might be on the fastest local broadband package but still not
satisfied with the speed?
speed is not jus determined by bandwidth...
dun forget latency....
read on to understand the whole network infrastructure and whether
u are getting ur money's worth from your ISP
***************
The term bandwidth in computer networking refers to the data rate
supported by a network connection or interface. One most commonly
expresses bandwidth in terms of bytes per second (bps). The term
comes from the field of electrical engineering, where bandwidth
represents the total distance or range between the highest and
lowest signals on the communication channel (band). (See
below)
Network bandwidth is not the only factor that determines the
"speed" of a network as perceived by the end user. The other key
element of network performance, latency, also affects network
applications in important ways.
What is Bandwidth?
Manufacturers of network hardware have done a great job of
promoting the concept of bandwidth. Virtually everyone knows the
bandwidth rating of their modem or their broadband Internet
service. Essentially, bandwidth represents the capacity of the
connection, and it's obvious that the greater the capacity, the
more likely that greater performance will follow.
Bandwidth can refer to both actual and theoretical throughput, and
it is important to distinguish between the two. For example, a V.90
modem supports 56 Kbps of peak bandwidth, but due to limitations of
the telephone lines and other factors, it is impossible for a home
dial-up network to actually achieve this level. Likewise a Fast
Ethernet network theoretically supports 100 Mbps of bandwidth but
this level can never be achieved in practical use thanks to
overhead in the hardware and in the computer's operating
system.
High Bandwidth and Broadband
In the Internet realm, networkers sometimes uses the term high
bandwidth to distinguish higher-performing Internet connections
from traditional dial-up access speeds. Definitions vary, but high
bandwidth connections support data rates of at least 64 Kbps and
usually 200 Kbps or 300 Kbps and higher. The definition of high
bandwidth differs from the definition of broadband. Technically,
the term broadband refers to the method of communication and
bandwidth refers to the amount of data that passes through the
connection over time.
Measuring Network Bandwidth
A number of tools exist for computer networkers to measure the
bandwidth of network connections. On LANs, these tools include
netperf and ttcp. On the Internet, numerous "bandwidth test" or
"speed test" programs exist, many made available for interactive
use through public Web pages. Anyone who uses these programs
quickly learns that bandwidth is a highly variable quantity that is
difficult to measure precisely. In a nutshell, typical network
architectures involve multiple layers hardware and software, as
well as time sharing.
Bandwidth is just one element of what a person perceives as the
speed of a network. Another element of speed, closely related to
bandwidth, is latency. Latency refers generally to delays in
processing network data, of which there are several kinds.
Latency and bandwidth are related... (see below)
... . Whereas theoretical peak bandwidth is fixed, actual or
effective bandwidth varies and can be affected by high latencies.
Too much latency in too short a period of time can create a
bottleneck that prevents data from "filling the pipe," thus
decreasing effective bandwidth.
Latency and Satellite Internet Service
Satellite-based Internet access service perfectly illustrates the
difference between latency and bandwidth. Sattelite Internet
connections possess both high bandwidth and high latency. When
loading a Web page, for example, most satellite users can observe a
short but noticeable delay from the time they enter a Web address
to the time the page begins loading. This high latency is due
primarily to propagation delay as the request message travels at
the speed of light to the distant sattelite station and back to the
home network. Once the messages arrive at home, however, the page
appears extremely quickly, often seeming to explode onto the screen
thanks to the high bandwidth of the incoming data.
Besides propagation delays, latency also may also involve
transmission delays (properties of the physical medium) and
processing delays (such as passing through proxy servers or making
"hops" on the Internet).
Measuring Network Latency
Network tools like ping and traceroute measure latency by
determining the time it takes a given network packet to travel from
source to destination and back, the so-called round-trip time.
Round-trip time is not the only way to specify latency, but it is
the most common.
Conclusion
Two key elements of network performance are bandwidth and latency.
The average network user is probably more familiar with the concept
of bandwidth, but latency matters too. Businesses use the term
Quality of Service (QoS) to refer to measuring and maintaining
consistent performance on a network by managing both bandwidth and
latency.