Problem with libqmi dhclient and Telit910 and ethernet

[Mark Wyllie]

Hi
I am struggling with the following configuration on my
I have a Beaglebone running libqmi, Debian Jessie and dhclient to bring up the cdc-wdm0 device .
I am using libqmi 1.16
It all worked perfectly and the wwan0 is giving me a great throughput.
I have spent around 3 days on this issue exploring DNS/ARP/DHCLIENT and various options. Reached a brick wall
I am now trying to bring up the eth1 interface (as a dongle).
I have read an unfortunate note from Nimbelink regarding this issue where they say:
“A QMI connection requires that any existing Ethernet connection be taken down. This is required so that the DHCP client serving the cellular link can correctly configure the system gateway and DNS resolver. “
http://nimbelink.com/Documentation/Development_Kits/NL-SWDK/30052_NL-SWDK_SkywireQMIAppNote.pdf

And unfortunately as soon as (around 5 seconds after ) I restart the eth1 interface, the system loses track of arp tables, so that the arp table goes from

(working)
arp-v
Address                  HWtype  HWaddress           Flags Mask            Iface
233.sub-166-250-218.myv  ether   02:50:f3:00:00:00   C                     wwan0
Entries: 1              Skipped: 0             Found: 1
To
>arp -v
Address                  HWtype  HWaddress           Flags Mask            Iface
233.sub-166-250-218.myv  ether   02:50:f3:00:00:00   C                     wwan0
192.168.0.2              ether   00:04:4b:5a:be:f6   C                     eth1
which works for about 5-10 seconds
and then degrades to:
>arp -a
? (166.250.218.233) at 02:50:f3:00:00:00 [ether] on wwan0
? (192.168.0.2) at 00:04:4b:5a:be:f6 [ether] on eth1
>
and then rapidly degrades to a DELAY in the arp entry and then FAILED.
And the ping google.com, DNS resolution etc all fails completely.
I do not use modem manager or network manager – just the simple /etc/network/interfaces with eth1 configured as static.

Is there any fix /workround to this.
I saw that ip tables might have some solution /idea to separating the icmp or arp packets out so that the interfaces are separate.
My aim is to have the eth1 as hotspot connected to the 4G but I can’t even get to stage 1!

Many thanks


Mark Wyllie


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