Mobile IPv6
Device support
As the modem establishes an IP(v4) PDP context with the network, to do IPv6 the modem would need to support it (or use a full PPP context).
Devices which do/don't support an IPv6 PDP type (there are AT commands to query the modem's capabilities):
Nokia E51 (IPv4/IPv6)
ATI Nokia AT+GCAP +GCAP: +CGSM,+DS,+W AT+CGDCONT=? +CGDCONT: (1-2),"IP",,,(0),(0) +CGDCONT: (1-2),"IPV6",,,(0),(0)
Huawei E220 (IPv4/PPP, IPv4/IPv6/PPP)
ATI Manufacturer: huawei Model: E220 Revision: 11.110.01.03.00 +GCAP: +CGSM,+FCLASS,+DS AT+CGDCONT=? +CGDCONT: (1-16),"IP",,,(0-1),(0-1) +CGDCONT: (1-16),"PPP",,,(0-1),(0-1)
ATI Manufacturer: huawei Model: E220 Revision: 11.117.10.02.00 +GCAP: +CGSM,+FCLASS,+DS AT+CGDCONT=? +CGDCONT: (1-16),"IP",,,(0-2),(0-4) +CGDCONT: (1-16),"PPP",,,(0-2),(0-4) +CGDCONT: (1-16),"IPV6",,,(0-2),(0-4)
Vodafone (Huawei) K4505 (IPv4/PPP)
ATI Manufacturer: Vodafone (Huawei) Model: K4505 Revision: 11.828.03.00.11 +GCAP: +CGSM,+DS,+ES AT+CGDCONT=? +CGDCONT: (1-16),"IP",,,(0-2),(0-3) +CGDCONT: (1-16),"PPP",,,(0-2),(0-3)
ZTE MF112 (IPv4/IPv6/PPP)
ATI Manufacturer: ZTE CORPORATION Model: MF112 Revision: BD_P671A2V1.0.2B05 +GCAP: +CGSM,+DS,+ES AT+CGDCONT=? +CGDCONT: (1-16),"IP",,,(0-2),(0-3) +CGDCONT: (1-16),"PPP",,,(0-2),(0-3) +CGDCONT: (1-16),"IPV6",,,(0-2),(0-3)
ZTE MF627 (IPv4/IPv6/PPP)
ATI Manufacturer: ZTE INCORPORATED Model: MF626 Revision: BD_P673M3V1.0.1B02 +GCAP: +CGSM,+DS,+ES AT+CGDCONT=? +CGDCONT: (1-16),"IP",,,(0-2),(0-3) +CGDCONT: (1-16),"PPP",,,(0-2),(0-3) +CGDCONT: (1-16),"IPV6",,,(0-2),(0-3)
Network support
I (met) have tried connecting with a K4505 and an A&A L2TP-handover SIM using a PPP context, but it doesn't work. An IP context gives you a CONNECT response immediately, with a PPP context it sits there for a couple of seconds before returning NO CARRIER.
I see the same results with a Vodafone contract data SIM.