Reg: IPv6 on MC7354

Bjørn Mork bjorn at
Wed Feb 8 08:57:05 UTC 2017

Balaji Sivakumar <shivbalaji1985 at> writes:

> Thanks Bjorn for the reply, I got the idea and it works for me well.
> Do you have any suggestions/ idea on creating dual stack connections on
> single /dev/cdc-wdm device ? we are getting 'Policy Mismatch error'.

I wonder if that is caused by trying to "convert" a single stack
connection to dual stack? 

QMI is (or was?  this might be fixed in newer versions?) weird wrt dual
stack.  There is no way to request an IPV4V6 context when connecting,
since you can only specify a single family per connection request.  But
only the first connection request will actually create a network
context.  The second one, for the second family, will simply return the
family specific data from the existing dual-stack connection.  Or fail,
if that connection is single stack.

One way to make the first connection dual stack is to predefine a dual
stack profile matching the APN.  I don't think this is supported in
qmicli yet, but you can use AT commands to do it:

 at+cgdcont=1,"IPV4V6", "yourapn"

You should check your list of configured profiles first, to make sure
you don't mess up a profile you want to keep and also make sure you
don't have any other (single family) profile for the same APN. If you
have then that might be selected instead and you end up with a single
family connection.

Then issue the two family specific connection requests referring to this

 qmicli -d /dev/cdc-wdm0 --client-no-release-cid --wds-start-network=apn=yourapn,ip-type=4
 qmicli -d /dev/cdc-wdm0 --client-no-release-cid --wds-start-network=apn=yourapn,ip-type=6

Don't know if this was what you already tried.  It's been a long time
since I did anything like this manually.  ModemManager tends to DTRT
nowadays, so I just lean on that.  If you are still having problems then
you should study what ModemManager does to initiate a dual stack


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