On 15/10/18 12:40, Neels Hofmeyr wrote:
On Fri, Oct 12, 2018 at 12:10:25PM +0200, Keith wrote:
With the split setup it involves a complete loss of service, basically, as you say, until location update timeout.
Not complete loss of service:
- any phone that contacts the network to get something done will be told to re-attach. So sending things and calling out (MO) will work.
Ah! Well that's something I did not know, I'm not sure it is what I observed (memory tells me not), but I'll check it all out again.
Another (less elegant) idea I'm having is that we do have some notion of which IMSIs were attached in the HLR database. They have the VLR number stored to match the MSC's identification. If we could employ some tool to graze the HLR db, and over a period of time invoke pagings for all those subscribers, we could blanket re-attach everyone within a short time. I think I'd make that an external tool using the CTRL interface, with some spread over time to not insanely load the network. The one mild problem with this is, it doesn't look like we notify the HLR on phones detaching. That could be resolved by also storing a timestamp of when a subscriber was last attached in the HLR, which I suggest makes sense anyway.
I suggest it does too. In fact, I think it is 100% necessary for the distributed GSM idea where we send broadcast probes to various HLRs asking them for the timestamps of the last seen LUR of an apparently attached (t)IMSI.
thanks!
k/