The Siri Test: How Much Bandwidth is She Using?
by February 29, 2012

Filed under: Performance Monitoring

In the age of smart phones, data plans and usage caps, many questions come up when looking into your cellphone bill.  It seems there are unlimited applications and features are swallowing up data. Have you ever wondered what else is using up your data? Checking mail, sending mail, playing games and using apps use data and affect your plan and your wallet.

Siri Bandwidth 1Take Apple’s newest iPhone, the 4S. The updated processor, storage and camera upgrades are significant, but the most well known is Apple’s voice recognition capability called Siri.  Apple’s Siri is a time saver and life saver in its most basic term. Before Siri, phones searched manually.  With the Siri enhancement, users can search the web, make calls, get directions, text and more using only their voice.  After the excitement of this feature wears off, the main question that comes up is: how will this affect my data usage?

So, I ran a Siri test. I ran some very basic commands using my iPhone 4S and Siri to find out how much data Siri consumes:

What is the weather going to be like tomorrow?

Play music

Text Fred “Call me after work”

Dial 781-555-5555

Remind me to call Bob tomorrow

I then analyzed all this information with AppNeta’s PathView Cloud using the packet capture capability called FlowView Plus.  Here is a breakdown of the tests and Siri’s data usage based on my requests.  Siri’s data usage fluctuates depending on the question asked. There are many different things you can ask Siri, from “Will it snow today?” to “How do I get to Proctor’s Theater?”   To keep with some sort of standard, I ran each of the captures only for 10 seconds and filtered just the info with my phone as the source or destination.

Siri Bandwidth 2

As you can see from the table, all of the requests differ in complexity. The more complex the question, the higher the data usage.  A simple question such as “what is the weather going to be like tomorrow?” creates 29.4 kB of usage whereas a request such as “Dial 781-555-5555” would create more traffic (38 kB) due to the breakdown of the numbers.  Specific questions often create a back and forth with Siri where the user asks one question, and Siri asks one back, waiting for another response.  Instances like this will obviously take up more data than a typical call request.

These requests create a good number of packets, as every function is broken down into packets. The report below displays packets on a per protocol basis, showing exactly which types of packets are used.  A portion of the packets are traveling over SSL adding a layer of security to the data required.

Siri Bandwidth 3

Siri is a time saver since the feature can eliminate typing, as well as a life saver due to the fact that texting is become a punishable offense and using Siri in that way allows you to text and drive without breaking the law or driving to endanger. However, when data usage is concerned, you must remember that, though Siri is a great capability offered with the new iPhone 4s, it is going to be generating more traffic than running your own queries.