Dual stack connection on EM7430

[Dan Williams]

On Wed, 2017-05-10 at 17:11 -0500, Balaji Sivakumar wrote:
> Hi,
> I have tried modem manager utility to setup dual stack connection for
> EM7430 using following steps, seems am able to create a dual stack
> connection. I have got queries to understand, Can you anyone share
> the
> ideas/comments.

<snip>

> 1.Is this the IPV6(2001::2:9153:6c2f:89af:a96d) address assigned
> through
> mmcli is dhcp-slaac address? Am only able to assign it statically.

This address is provided by the modem firmware, not through IPv6 SLAAC.
   With QMI, IPv6 addressing is always static and provided by the
modem.  Simply set that address on the interface, exactly like you have
already done, create a default route to the given IPv6 gateway, add the
given IPv6 DNS servers to /etc/resolv.conf, and you're good to go. 
SLAAC and DHCPv6 are not required.

> 2. if i understand qmilci has the limitation on dual stack
> connection, is
> this right?

qmicli can certainly do a dual-stack connection, but it works the same
way QMI does internally.  You create two WDS clients, one for v4 and
one for v6, connect each one separately, get each's IP configuration
separately, but apply that config to the same net interface.

qmicli -d /dev/cdc-wdm0 --client-no-release-cid --wds-start-network="apn=foobar,ip-type=4"
qmicli -d /dev/cdc-wdm0 --client-cid=<from step #1> --client-no-release-cid --wds-get-current-settings

qmicli -d /dev/cdc-wdm0 --client-no-release-cid --wds-start-network="apn=foobar,ip-type=6"
qmicli -d /dev/cdc-wdm0 --client-cid=<from step #3> --client-no-release-cid --wds-get-current-settings

(or something like that)

Then use the output from each get-current-settings to configure the net
interface.

Dan

> 
> 
> 
> On Wed, Apr 12, 2017 at 2:38 PM, Aleksander Morgado <
> aleksander at aleksander.es> wrote:
> 
> > On Wed, Apr 12, 2017 at 9:14 PM, Dan Williams <dcbw at redhat.com>
> > wrote:
> > > > Have tried both the options but i still get the policy mismatch
> > > > error
> > > > when
> > > > i try to activate for ip-type=6, even the profiles support both
> > > > IPV4
> > > > and
> > > > IPV6, it allows to create a network either one of them.
> > > > 
> > > > It should be like this right, if we don't specify the ip-type
> > > > option
> > > > as
> > > > part of start-network should be able to transmit message using
> > > > both
> > > > IPV4
> > > > and IPV6.
> > > 
> > > Last I checked with Verizon (over a year ago), specifically with
> > > VZWINTERNET on an MC7750 and UML290, the behavior that you are
> > > doing
> > > was how the Verizon Broadband Access Manager (VZAM) operated to
> > > acquire
> > > an IPv4 and IPv6 address.  And yes, the modem had VZWINTERNET
> > > with a
> > > V4V6 PDP context as shown by CGDCONT.
> > > 
> > > 1) create a WDS client
> > > 2) call StartNetwork with ip-type=v4
> > > 3) get current settings with client from #1
> > > 4) create a new WDS client
> > > 5) call StartNetwork with ip-type=v6
> > > 6) get current settings with client from #4
> > > 
> > > Both v4 and v6 addresses get configured on the same network
> > > interface,
> > > but are acquired through different WDS clients and StartNetwork
> > > requests.  As far as I know, QMI has no "v4v6" ip-type attribute
> > > for
> > > StartNetwork.
> > > 
> > > Perhaps that's changed, would be nice to verify what VZAM or
> > > other QMI-
> > > based Windows connection managers are doing these days to get a
> > > dual-
> > > stack connection.
> > 
> > In ModemManager the flow is a bit different to request this same
> > setup. Instead of calling StartNetwork with a given "IP Family
> > Preference" TLV (as you would have with
> > --wds-start-network="ip-type=X"), we instead call the "WDS Set IP
> > Family" command before calling "WDS Start Network" and if that
> > succeeds, we won't add the TLV. Only if the "WDS Set IP Family"
> > command fails, we do set the TLV.
> > 
> > We could test this approach if we had a --wds-set-ip-family command
> > in
> > qmicli, but we don't yet; patches welcome :)
> > 
> > --
> > Aleksander
> > https://aleksander.es
> > 
> 
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