Detect Roaming

[cyphorious]

Hello!

I need to write an application, that detects roaming from one access point to another if I'm connected to WLAN. Unfortunately I couldn't find anything that detects roaming for me. All I could find are some explanations in the Bearer API. One sentence says:

The second form of roaming is referred to as Forced Roaming. The system simply changes the link layer without consulting the application. It is up to the application to detect that some of its internal socket may have become invalid.

Since I'm not a network guy I don't have any idea how I could track roaming. It would be enough to know, that the device switched from one access point to another.

Maybe anybody of you can help me out on that?

Thanks a lot!

[rahulvala]

QNetworkSession is the central class for managing roaming related issues.

Class : QNetworkSession

[cyphorious]

It seems, that this only works when my device switches the network. What I want to achieve is to get notified when my device switches Access Points INSIDE one network.

Let's say you have a home network with 3 access points (one in each floor). you are in the first floor connected to your network on access point 1. now you go upstairs and access point 2 offers a better signal strength than access point 1. now your device will switch to access point 2. and this is the event I want to catch.
But in this case - I think - the configuration does not get changed, so QNetworkSession#activeConfigurationChanged or QNetworkSession#preferredConfigurationChangend will not trigger.

[james1980]

Hi cyphorious,

I think the QNetworkSession#preferredConfigurationChangend signal should be emited when access point are changed.

Hav you tried if this signal is emitted or not?

[cyphorious]

Yes, I've tried QNetworkSession#preferredConfigurationChangend, QNetworkSession#activeConfigurationChangend and QNetworkSession#stateChanged (with asking for QNetworkSession::Roaming) but none of them triggered inside my network. I think this is because the configuration does not change in the case of roaming inside a network, but only when you switch between networks (one configuration for each network). That's my guess at least.

Is it possible to catch the hardware address of the access point I'm connected to? Haven't found anything for that, but this could be another approach.

[james1980]

Have you taken a look at the bearer management API 's bearer monitor example. It may be provide some help.

[cyphorious]

Yes I did. And it indeed helped me in many ways, but not in my particular problem with access point roaming inside one network.

[petrib]

If not in Qt and, and this is about Symbian, you can use Symbian C++ calls to get the cell ID. If the cell ID changes, you've experienced a cell handover (which, unless you're really standing in cell edge conditions, means that you've moved as your connection moved (was handed over) from one cell to another.

If you move also from a network operator's IP address routing area to another, then the local IPv4 address for an active connection for the phone probably changes, too. (The routing area will cover many cells, so it won't change for every handover as long as you are within the same routing area.)

[Roose]

If you move also from a network operator's IP address routing area to another, then the local IPv4 address for an active connection for the phone probably changes, too. (The routing area will cover many cells, so it won't change for every handover as long as you are within the same routing area.)

Did you mean that Routing Area Update in cellular network would change devices local IP address?

I believe local IP address will stay the same during entire connection and connection must be rebuilded if operator or country changes. In this case local ip is given from new operators address pool.

[divanov]

Sorry, I didn't read the whole thread, so I might be repeat something.
There are two types of roaming, between access points and different operator networks.
The latter can be detected through Qt Mobility QSystemNetworkInfo
http://doc.qt.nokia.com/qtmobility-1...kStatusChanged
while the former is done through Qt (since 4.7) QNetworkSession
http://doc.trolltech.com/latest/qnet...l#stateChanged