Hello Harald,
On Mon, 2 Nov 2009 22:47:18 +0900, "Harald Welte" laforge@gnumonks.org wrote:
This is actually very funny. According to the protocol, a RA update should only be performed if the MS was/is already GPRS ATTACHED to this network before. It clearly wasn't in this case, as the OpenBSC network never offered GPRS support. Still, it tries it. That's why we're rejecting it.
Not sure if I understand it in detail, from my understanding an RA Update is performed when the Routing Area has changed (or the periodic RA update timer has expired). So if the phone is already attached to a network, shouldn't we receive the RA update if it selects our new RA ?
Best regards, Dieter
On Mon, Nov 02, 2009 at 11:03:42PM +0000, Dieter Spaar wrote:
Hello Harald,
On Mon, 2 Nov 2009 22:47:18 +0900, "Harald Welte" laforge@gnumonks.org wrote:
This is actually very funny. According to the protocol, a RA update should only be performed if the MS was/is already GPRS ATTACHED to this network before. It clearly wasn't in this case, as the OpenBSC network never offered GPRS support. Still, it tries it. That's why we're rejecting it.
Not sure if I understand it in detail, from my understanding an RA Update is performed when the Routing Area has changed (or the periodic RA update timer has expired). So if the phone is already attached to a network, shouldn't we receive the RA update if it selects our new RA ?
a routing area change is a routing area change within one network. if it enters a new network (different MCC/MNC), it needs to gprs attach to this network first.
On Mon, Nov 02, 2009 at 11:03:42PM +0000, Dieter Spaar wrote:
Hello Harald,
On Mon, 2 Nov 2009 22:47:18 +0900, "Harald Welte" laforge@gnumonks.org wrote:
This is actually very funny. According to the protocol, a RA update should only be performed if the MS was/is already GPRS ATTACHED to this network before. It clearly wasn't in this case, as the OpenBSC network never offered GPRS support. Still, it tries it. That's why we're rejecting it.
Not sure if I understand it in detail, from my understanding an RA Update is performed when the Routing Area has changed (or the periodic RA update timer has expired). So if the phone is already attached to a network, shouldn't we receive the RA update if it selects our new RA ?
As it turns out, this really seems to be the case. So even while switching from one mobile network (MNC/MCC) to another, the MS can apparently just perform a RA update and does not have to do a GPRS attach. This explains the beahvior.
It's still quite weird to me, but well, at least we know the phones in question are behaving like they should.
-
Dieter Spaar -
Harald Welte