≡ Menu

Ford on Feature Interaction

On the Pulver Blog, Carl Ford has written a short piece on feature interaction.  He notes that the web model for SIP doesn’t seem to be being applied as one would expect.  In effect, telecom companies are rolling out SIP services to their islands, because they don’t want to pass control of the call to a proxy.  Feature interaction is the boogeyman that gets raised.  Feature interaction is the idea that some features may interact differently from expectations because of interactions with other features.  For instance, try setting up Vonage’s simul-ring feature on your home phoneline so that it rings your cell phone as well as your landline, and then phone your house from your cellphone.  You can’t call home any more because your cell phone voice mail picks up every time. If you’re interested in more information on feature interaction, check out the ICFI ’05 web site.  ICFI is a somewhat regular conference on feature interaction which has been running since the mid 1990’s. 

Feature interaction is the concern raised, but isn’t this really just a case of a poorly designed feature?  To use the Vonage example again, shouldn’t Vonage’s proxy have the brains to be able to figure out that it’s one of the simul-ring phones initiating the call?  I suspect the real issues are security and billing issues.  For instance, have billing systems been designed to handle the case of what happens when the call goes off network, and potentially returns later. 

{ 3 comments… add one }

  • Carl Ford June 5, 2006, 1:13 pm

    I still think its one of interaction. The model you brought up of VONAGE is a good one, since they are not in control of the wireless network (yet ;

  • Alec June 6, 2006, 2:15 am

    No doubt, Carl. I think feature interactions can be designed for. I guess what I am questioning is whether it makes business sense for the network operator to design for them.

  • Carl Ford June 6, 2006, 6:16 am

    I think that we are in violent agreement. What that means to me though is that the network is going to continue to fracture. In effect the Internet has come back to its roots. An Inter network of Virtual Networks.

    Some how this does not feel like the mission of the standard.

Leave a Comment