How tomcat is handling bandwidth sharing across all request

Question

We are developing small video hosting application ,we are not writing any special program for open the video file and send to player , simply we are using tomcat DefaultServlet for above all video request , now we have to benchmark our application for following scenario

1) video size 100MB (1080i HD)
2) Total Network bandwidth 10Mbps (IN/OUT)

Now how to calculate how many max thread is allowed for above scenario ,with out interrupting users viewing experience, here each video response should secure 400kbps bandwidth for no interruption

So my question is how many concurrent users can view videos without interrupt then how to test this scenario ,and how tomcat is handling bandwidth sharing across the request

Answer 1

Tomcat doesn't do any bandwidth sharing internally; that's up to your OS and network infrastructure. Basically divide your network bandwidth's slowest point (probably the ISP connection) by the 400k you say you need per connection. That is the number of simultaneous connections you should be able to support, assuming your server hardware can handle it (which it probably can).

Comments

There are lots of other factors to consider as well. A naive client might download the entire movie before playing it. Disconnects might end up higher than zero, so the client will have to tr-try and -- it being a naive client -- might just re-start from the beginning. A marter client might be able to do a HEAD request to get the file size and then use separate requests for chunks of a single file. If the client thinks its being smart (but is really dumb), it might request those chunks simultaneously "to improve performance".

If your 400kbps requirement per connection is well-researched and correct, then you can handle:

 (X bandwidth in kbps) / (0.7 * 400 kbps)

The 0.7 factor is a rough estimate of network "waste" chatter required to actually communicate. For example, if you have a 100Mbps connection, you can't actually communicate data at that speed: the connection supports bits moving at that speed, but there is more data flying around than the data your application cares about.