10 times more bandwidth is not 10 times faster

Complaints from the users about poor response time or an altogether missing connection to the internet, often results in the it-department investing for more bandwidth. But how much do we need, and from which parameters should we choose our new bandwidth?

Internet connections are not “just” internet connections, so what can we expect from a new connection with increased bandwidth?

We will take a look at an example where we upgrade from a 10 Mbit/s fiber to a 100 Mbit/s fiber anticipating that when we increase the internet bandwidth tenfold, then we also increase the user’s speed tenfold.

But before we continue with the example, it is important that we take a look at the properties of an internet connection and which impact these different properties have on the internet connection.

Property 1: Bandwidth [bit/s]
In daily speech, the bandwidth is what we associate to the speed of the internet connection, and that is typically also what we buy when we choose an internet connection. Bandwidth is typically presented in bit/s, kbit/s, Mbit/s or Gbit/s.

Depending on our need for upload and download on the internet, we can choose a symmetrical or an a-symmetrical connection. A symmetrical connection is a connection where there is the same amount of bandwidth for download and upload (e.g. 10+10 Mbit/s), on an a-symmetrical connection there is more bandwidth for download than upload (e.g. 2 Mbit/s download + 512 kbit/s upload).

When choosing an a-symmetrical connection it is important that the relation between download- and upload bandwidth is no more than 7:1, because the connection then, cannot always be used to the optimum effect. Thus, the low upload bandwidth cannot keep up, when acknowledgement packets are being sent on the downloaded data.

Property 2: Delay [ms]

All internet connections have delays which are measured in milliseconds [ms]. The delay we as users experience is from the time we click the Enter key, until a webpage turns up on our screen. The delay can vary from a few milliseconds to more than halves of seconds.

Another type of delay which is not directly dependant on which type of internet connection we have, is visiting an overloaded website which typically will result in further delays. A good example is the Danish Customs and Tax Administration when annual tax returns are ready – then, the “delay” can last for hours.

Delays on internet connections are called Delay, Latency, Round Trip Time (RTT), Ping-time, Lag, etc.Examples of different types of connections and their built-in delay:• ADSL: 20 ms• Fiber: 1 ms• Fiber (Denmark–USA): 140 ms• Satellite: 600 ms

Property 3: Packet loss [%]

As users we would like to avoid packet loss. A large packet loss (>1 %) give problems with VoIP and in general, a poor exploitation of the connection. A large packet loss gives many retransmissons of data packets which are lost and thus, gives unnecessary delays. The reason for packet loss can e.g. be caused by an overloaded internet router which isn’t dimensioned correctly to the size of the connection or the number of users.

Packet loss is measured in percentage and is the difference between number of packets sent and number of packets reaching the recipient.

Property 4: Price, Service Level Agreement (SLA), uptime, time of reaction when reporting an error, …  

The fourth property might not be directly referable to the internet connection itself, but these issues are still very important parameters during daily operations, and expresses the support we want in relation to our internet connection. We can see it as a kind of insurance, that we are quickly able to go online and work again if we should have been so unfortunate as to lose our internet connection. It is here we experience a big difference in the level of support that the internet providers offer as a standard and what they offer as additional services. And remember that there is a good reason for private internet connections being cheaper than that of businesses.

When we have decided which bandwidth, which delay, which media and the time of reaction at the internet provider, then we are ready to upgrade our internet connection.

Do we then get what we expect, when we upgrade the bandwidth?

As stated, there are many elements that come into play when purchasing bandwidth, and normally we do not get quite what we think we get, but what is then to be expected when we e.g. increase our bandwidth tenfold?

Let us go back to our example upgrading from 10 Mbit/s to 100 Mbit/s.

We will start out measuring the time it takes to fetch CNN’s website with a 10Mbit/s fiber connection and, with a 100 Mbit/s fiber connection. Measurements are performed in Wireshark.

CNN.com’s frontpage takes up 2,8 MB = 22 Mbit.

If we only use a simple mathematical formula to calculate the transferraltime from the amount of data and the connection’s bandwidth, Time=Amount/Bandwidth, we get:

  • 22 Mbit / 10 Mbit/s = 2,2 s
  • 22 Mbit / 100 Mbit/s = 0,22 s

But our measuring shows that the real world is more nuanced, and that there are also other factors making an impact than just raw bandwidth. For instance, a webpage is transferred in smaller parts as both the webserver and webbrowser agrees on what should be transferred.

Actual measure at 10 Mbit/s: 9,2 s 

9,2 s total – 2,2 s connection = 7 s overhead

Impact from upgrading: from 10 Mbit/s to 100 Mbit/s 

100 Mbit/s: 7 s overhead + 0,22 s connection = 7,22 s

Reduction: from 9,2 s to 7,22 s = -20% response time

As users we perceive the speed of the internet connection as the time from when we have pushed Enter, until the website appears, and in our test, when increasing the bandwidth tenfold, we are only reducing response time with 20%. Or, you can also see it as increasing bandwidth tenfold, the connection speed only increases with 27% for the users.

Overhead: A part of your bandwidth speed is used for information that is not immidiately visible. This is called “overhead”. When information is sent through the internet, the information is divided into packets. Every packet is assigned some data to make sure that the packet ends up in the right place. The packets take up space in the data current and these extra pieces of information will thus add a delay in the response time.

SmartShare StraightShaper cannot remove the overhead on the connection, but it optimizes the utilization of the bandwidth and stabilizes the connection.

SmartShare also divides the bandwidth equally among the users so that all users will benefit from the increased bandwidth and not just the bandwidth gobbling users as is the case on an internet connection without SmartShare.

Learn more about how the internet works with, and without SmartShare.