Hey, > > We're using a Cinterion ELS61-E R2 modem and ModemManager-1.14.0. > > It looks like we're facing a PDN activation problem which maybe caused > > by ModemManager. > > > > Our modem is happily connected, using 4G and PDP Context ID (CID) 1. > > The CID refers to type=ipv4 and APN=blablabla.com.bla.bla.gprs. > >
In the effort of obfuscating the info, you rewrote a key part of that APN string making it very difficult to understand :) That "bla.bla" at the end refers to the MNC and the MCC of the network, and when a context APN is shown like that, you can assume that's the initial EPS bearer that's already connected as soon as you're registered. So, the modem registers in the network, you run CGDCONT? and you get CID=1 reported with APN "blablabla.com.mnc001.mcc002.gprs". That means your modem is registered in the network with MCC 002 and MNC 001 and APN blablabla.com. If you attempt to now launch a connection with APN "blablabla.com", ModemManager will lookup an exact APN match, and for the purposes of APN matching, "blablabla.com.mnc001.mcc002.gprs" matches the APN "blablabla.com", so that's why CID=1 is used while in LTE. > > The APN to use is actually blablabla.com but MM reports: > > > > <debug> [1613584864.390514] [modem0/bearer0] found 3 PDP contexts > > <debug> [1613584864.391031] [modem0/bearer0] PDP context [cid=1] > > [type='ipv4'] [apn='blablabla.com.bla.bla.gprs'] > > <debug> [1613584864.391381] [modem0/bearer0] PDP context [cid=2] > > [type='ipv4'] [apn=''] > > <debug> [1613584864.391730] [modem0/bearer0] PDP context [cid=3] > > [type='ipv4'] [apn='blablabla.com'] > > <debug> [1613584864.409742] [modem0/bearer0] looking for best CID > > matching APN 'blablabla.com' and PDP type 'ipv4'... > > <debug> [1613584864.410388] [modem0/bearer0] found exact context at CID 1 > > > In general the UE is allowed to enable an APN only once. > Some modems bridge internally when you use a different CID for attach > and for the data PDN. > AFAIK it is not the case for Intel chipsets (ELS61), and therefore MM > should use CID1 only (because it is used for the attach). That is what happened while in LTE, yes. > > For 3G, obviously it fails: two (activated) CIDs are simply 2 > contexts, and must have different APNs. > I don't understand this statement Giacinto. While in 2G/3G, the logs from Norbert show that running CGDCONT? show no APN already connected, and CID=1 reports the empty APN and not the initial EPS bearer APN as the modem isn't registered in LTE. The CID lookup done by ModemManager ends up finding the context with CID=3 and APN "blablabla.com" and it tries to connect that one, only that one, no other one. Why would it fail like that? -- Aleksander https://aleksander.es _______________________________________________ ModemManager-devel mailing list ModemManager-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/modemmanager-devel
