Exepected transfer times

[digiposter]

Using DSL reports. I've found out that my upload speed is about 750K.

If I want to transfer a 4 gig file to another cable modem user. 1.5M Download speed. How long would you expect this to take?

The reason I ask is because I download 4 gig files from other facilities using digidelivery and it's just over an hour. I'm seeing it take 24 hours.


Question 2
It also took about an hour to upload to the digidelivery unit which was longer than I expected.
Does the compression happen within the software before it goes to the Digidelivery Unit? Or within the digidelivery box?
If within the Digidelivery box, is that why it takes so long to upload to the unit? Or do I have an internal network problem?

Thanks in advance!

[Gordon Lyon]

There are a lot of factors that affect upload and download speeds. The rule of thumb is that the smallest pipe in the connection is the limiting factor. If you're working with a DigiDelivery server on your LAN and your DSL upload speed is limited to 750k, that will be the limit of anyone else's download speed. If you're actually using a server on another network, the limiting factor is either going to be that network's connection speed to their ISP, or the recipient's connection speed to their ISP - whichever is slower. Does that make sense?

In any case, you need to be aware of the difference between theoretical and actual throughput. Inefficiencies like latency, dropped packets, overall network traffic, solar flares, etc. all contribute to bringing actual throughput down to something substantially below theoretical throughput - often by as much as 90%. This is why it's always hard to predict actual transfer times. However, there are some tests you can run if you have a DigiDelivery server on your network to make sure that you're not accidentally routing stuff through the ISP when you don't need to. See Testing Performance on page 20 of the Admin Guide.

To answer your specific question, yes the compression and encryption are performed on the workstation before posting to the server, and could be contributing to the upload time. The additional time required to perform the compression is usually more than made up for in the savings on Internet transfer time. However, the gain depends on the material: Files which are already heavily compressed may take a long time to process and not shrink much. AC-3 files are a good example of this. Also, If your delivery is not going out over the Internet but is simply going to be downloaded by someone else on your network, it's probably faster to bypass the compression. You can always test this yourself by unchecking the "Optimize for Internet Delivery" checkbox.

Thanks, Gordon