# HL8548 CDC ethernet connection problem (Linux)

**URL:** <https://forum.sierrawireless.com/t/hl8548-cdc-ethernet-connection-problem-linux/8652>\
**Category:** Legacy HL Series\
**Created:** [July 11, 2016, 9:43am UTC](https://forum.sierrawireless.com/t/hl8548-cdc-ethernet-connection-problem-linux/8652 "2016-07-11T09:43:19Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Nazdravi](https://avatars.discourse-cdn.com/v4/letter/n/43a26b/32.png) [@Nazdravi](https://forum.sierrawireless.com/u/Nazdravi)\
**Post date:** [July 11, 2016, 9:43am UTC](https://forum.sierrawireless.com/t/hl8548-cdc-ethernet-connection-problem-linux/8652/1 "2016-07-11T09:43:19Z")

</div>

Hi all,  
since I have registered my modem device to Sierra Airvantage it often fails to setup a CDC ethernet connection. After switching on power it seems that a connection already exists but it is unusabe within the operating system.

```auto
AT+CGDCONT?
+CGDCONT: 1,"IP","internet.eplus.de","0.0.0.0",0,0
+CGDCONT: 5,"IP","internet.eplus.de","10.198.65.111",0,0
OK
AT+WPPP?
+WPPP: 2
OK
AT+XDNS?
+XDNS: 1, "0.0.0.0", "0.0.0.0"
+XDNS: 5, "212.23.103.4", "212.23.103.8"
OK
AT+CREG?
+CREG: 2,1,"9D1D","08AD768F",6
OK
```

With the known sequence

```auto
at+wppp=1,1,"blau","blau"
OK
at+xdns=1,1
OK
AT+xcedata=1,0
  <== firing up dhcp client on different terminal
    [root@lw-dimm-cpu12 ~]# udhcpc -f -i eth1
    udhcpc (v1.22.1) started
    Sending discover...
  >
+CME ERROR: 4 (some times also error 100, some times ok)
```

the resulting state can be a working ethernet interface (in the minority of attempts) or ending up with an xcedata error. It seems that parts of the connection automaticly become established (valid nameservers are listed for cid 1). Any ideas to run a stable internet connection setup or to force the module to a defined initial state before attempting to start the connection? The modules firmware version is RHL85xx.5.5.18.0.201506301553.x6250\_1.

Before booking in at Airvantage the state was as follows and connection attempts succeeded regularly:

```auto
at+wppp?
+WPPP: 2
OK
at+wppp=1,1,"blau","blau"
OK
at+cgdcont?
+CGDCONT: 1,"IP","internet.eplus.de","0.0.0.0",0,0
OK
at+xdns=1,1
OK
at+cmee?
+CMEE: 1
OK
AT+xcedata=1,0
  <== firing up dhcp client on different terminal
    [root@lw-dimm-cpu12 ~]# udhcpc -f -i eth1
    udhcpc (v1.22.1) started
    Sending discover...
    Sending select for 10.115.99.251...
    Sending select for 10.115.99.251...
    Sending select for 10.115.99.251...
    Lease of 10.115.99.251 obtained, lease time 172800
    deleting routers
    adding dns 212.23.103.9
    adding dns 212.23.103.8
  >
OK
```

Kind regards  
Arndt