Zyxel XGS1250-12 V2: SPF lowerlayerdown

Installing and Using OpenWrt
1

Hi everyone,

I am running OpenWRT v24.10.2 on a Zyxel XGS1250-12 V2 network switch. I have plugged in an Zyxel PMG3000-D20B GPON modem in the SFP slot, and want to access its configuration interface which is available at 10.10.1.1.

So I added a new interface in the wan zone in LuCi, setting a static IP address from that network, but ip a shows the interface as NO-CARRIER LOWERLAYERDOWN:

11: lan12@eth0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue master switch state LOWERLAYERDOWN group default qlen 1000
    link/ether 72:49:a2:16:a5:b6 brd ff:ff:ff:ff:ff:ff permaddr 00:e0:4c:00:00:00
    inet 10.10.1.2/24 brd 10.10.1.255 scope global lan12
       valid_lft forever preferred_lft forever

What does that mean? While there is indeed no fiber plugged in currently, I should be able to access the modem' internal configuration, right? Or am I missing something?

Thanks a lot!

2

On my Zyxel PMG3000-D20B, the configuration interface is on 10.10.1.1.

No...without a active fiber plugged in, the interface stays down.

3

You're right, that's what I meant (see the ip a output above), the address in the post was just a typo, I corrected that.

With the stock firmware on the network switch, I'm able to access the fiber modem even without plugging a fiber in. I just plugged my laptop into the switch and gave myself an IP in the 10.10.1.1/24 range, and it worked. That's why I'm wondering why it doesn't work with OpenWRT, does LOWERLAYERDOWN mean the SPF port is not yet supported by OpenWRT?

4

Since i've got only a Banana Pi BPI-R3 where i can plug the GPON module in, i get a different output on the regarding port:

3: sfp1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN qlen 1000
    link/ether 42:6d:31:xx:xx:xx brd ff:ff:ff:ff:ff:ff
    inet 10.10.1.2/24 brd 10.10.1.255 scope global sfp1
       valid_lft forever preferred_lft forever
    inet6 fe80::406d:31ff:fe31:3144/64 scope link 
       valid_lft forever preferred_lft forever

As i still haven't got the fiber connected (with no schedule from the executing company), that's the only thing i can offer at the moment.
Maybe this NO-CARRIER LOWERLAYERDOWN just happens only on your Zyxel switch.

Edit:
I just found this useful link which explains the difference between down and lowerlayerdown.