As files grow in size they become challenging to move using traditional file transfer methods. This is where file transfer acceleration comes in, turning transfers that can take hours or even days into transfers only taking a few minutes.
When evaluating Internet connectivity both business and consumer users have traditionally looked at the download connection performance as the most important. The speed and reliability of accessing data, whether for web browsing, downloading files, watching streaming movies, listening to music, or viewing webcasts, was considered the highest priority.
More recently applications and operations including data backup, video uploads, file storage, multi-site collaborations and uploading to cloud based services has increased the importance of upload connectivity.
Let’s first take a look at the issue of file size.
Sending large files can be both difficult and expensive depending on the method chosen. Attachment size limits often prevent sending via email. FTP is simple but can be slow and unreliable. Shipping on physical storage solutions is costly and very slow. Proprietary protocols based on UDP can be very expensive, complex to install and manage, and not as flexible as TCP.
The issues associated with transferring files include security, reliability, efficient workflow integration, and many others. But the overriding issue is the speed of the transfer, in order to better appreciate the size of files today have a look at the following chart.
|Average File Size||File Type|
|1 kB||a short email;
or small image
|8 kB||Typical size of a single image file
(about 200 x 200 pixels PNG or GIF)
|30 kB||the maximum recommended size for a JPEG image on a web page (approximately 640 x 480 pixels )|
|50 kB||The maximum recommended total of all the elements on a single web page, including images and HTML|
|500 kB||A 5-page word-processor document with some embedded images|
|3.5 MB||MP3 Song|
|10 MB||Maximum size of an email that you can expect all recipients to receive|
|700 MB||Maximum amount of data on one CD-ROM|
|5 GB||Amount of data on a DVD-ROM USB flash drive
|500 GB||Typical hard drive size on a computer|
|2 TB||Large external backup hard drive|
It’s also important to keep in mind that uncompressed formats are even larger than the file sizes listed here. For example, an average mp3 file is approximately 3.5 MB but an uncompressed song is closer to 50 MB in size.
Now that we have an idea of the size of files we are trying to upload let’s have a look at why it takes so long. There may be many contributing factors but often it is simply your connection. If you try to share video files, or back up virtual machines, archive music, movies, or even photos to the cloud, you find out quickly that it can be a long, tedious wait.
Upload speed is very important. It has a noticeable effect on overall speed, and if you’re trying to upload large files it can dramatically affect your productivity and costs. If you’re unsure what your connection speed is, you should test it or preferably monitor it on an on going basis. Two key metrics are of course upload speed and latency.
Aside from the obvious download/upload numbers, there’s latency, which is measured in milliseconds (ms). The higher the latency the slower the upload.
It might be easier to think of latency as response time, but the determining factor with regard to latency is length. How far away is the server you’re trying to communicate with? If your destination server is 100 KM away there is a 200km round trip.
Light travels at 200,000 km per second. So, if our connection were perfect, we could see a 1.0 ms Round Trip Time. If the destination is much further say Australia (approximately 25,000km round trip from my location) the theoretical best RTT is125 ms. With even minimal packet loss and other overhead issues this can easily double.
The following chart shows the approximate time it would take to upload 1GB, 100GB, and
1TB of data using common upload speeds: 1Mbps, 10Mbps, 100Mbps and 1Gbps
|1 GB||100 GB||1 TB|
|1Mbps||2.5 hours||10 days||99 days|
|10Mbps||14 min||1 day||10.2 days|
|100Mbps||1.5 min||12 hrs||5.1 days|
|1Gbps||8 sec||15 min||2.5 hrs|
Times are rounded and an overhead of 10 % is assumed.
To calculate your own examples check out http://www.numion.com/calculators/time.html
The first step is to consider improving the quality of your connection. While you can’t argue with physics (the speed of light is a constant) overhead issues can be mitigated with various WAN optimization tools, application acceleration tools and network metrics monitoring. The other option is to ensure you are getting the bandwidth you have been paying for and, if necessary change providers or add bandwidth.