VDSL connection problem on lantiq/xrx200

Ordovician · May 8, 2026, 1:38pm

VDSL Connection Problem (lantiq/xrx200)

Keywords: VDSL, lantiq, xrx200

My home Internet connection has been stable for almost 5 years with OpenWRT running on a Plusnet Hub One modem-router (lantiq/xrx200). Last week, the connection stopped working completely. I am now unable to connect.

There are no obvious error messages in the system logs. The hardware appears to be working correctly, but nothing is logged in /sys/class/net/dsl0.101/statistics. In LuCI, the status of the VDSL interface is:

Carrier: Absent
RX: 0 B (0 Pkts.)
TX: 0 B (0 Pkts.)
Error: Network device is not present

I have attempted to troubleshoot the problem with three separate devices:

Plusnet Hub One running OpenWRT 25.12.2
Plusnet Hub One running OpenWRT 24.10.6
Plusnet Hub Two running stock firmware

Internet connectivity fails on both of the OpenWRT routers, however the connection is fine on the stock router. Based on these findings, I conclude that the connection issue is not caused by faulty hardware, since its unlikely that two routers have failed simultaneously. It must be a software configuration issue.

Does anyone here know why I cannot connect using my OpenWRT devices? Thank you in advance for any help received.

My Settings

Here are the DSL settings in /etc/config/network:

config dsl 'dsl'
        option annex 'b'
        option tone 'a'
        option ds_snr_offset '0'
        option xfer_mode 'ptm'
        option line_mode 'vdsl'

config interface 'vdsl'
        option proto 'pppoe'
        option device 'dsl0.101'
        option username '***'
        option password '***'
        option ipv6 '0'
        option keepalive '6 20'
        option mtu '1492'
        option peerdns '0'
        list dns '9.9.9.11'
        list dns '149.112.112.112'
        option multipath 'off'
        option sourcefilter '0'
        option delegate '0'

config device
        option name 'dsl0.101'
        option type '8021q'
        option ifname 'dsl0'
        option vid '101'
        option multicast '0'

Here are some connection statistics provided by the Plusnet Hub Two router:

Data rate: 4.3 Mbps / 19.4 Mbps
Maximum Data rate: 4.4 Mbps / 21.0 Mbps
Noise margin: 5.6/6.1
Line attenuation: 42.5/50.2
Signal attenuation: 49.2/50.4
VLAN id: 101
Upstream error control: Off
Downstream error control: Off

Speculation

It is strange that the connection fails suddenly now after several years of use. Perhaps Plusnet or BT have made changes to the connection settings or to the hardware/software setup at the local DSLAM.

I suppose that the most likely causes of the error are:

Authentication/PPPoE/ISP-side change requiring something the stock router does differently at PPPoE time (PPP options, padi/pado handling, discovery timing or specific LCP/CHAP settings).
Link-layer or device configuration mismatch (MTU, FCS/CRC offload, MAC/PHY flags) that prevents carrier discovery even though the interface appears present.
Some ISPs bind sessions to a device/modem MAC address. Is this now the case for Plusnet/BT OpenReach?

frollic · May 8, 2026, 1:47pm

you can always clone the MAC from the working device, to the other two.

MisterW · May 8, 2026, 1:57pm

I can assure you, Plusnet don’t bind sessions to a MAC.

It sounds to me like to dsl interface isnt running.

SSH to the Hub one and post the results of running /etc/init.d/dsl_control status

Ordovician · May 8, 2026, 2:09pm

Thanks for the reply. Here is the result:

root@OpenWrt:~# /etc/init.d/dsl_control status
running

MisterW · May 8, 2026, 2:16pm

Thanks. From my limited knowledge of how the dsl interface works, that looks ok.

Are there no logs at all from pppd ?

edit: can you try /etc/init.d/dsl_control dslstat

MisterW · May 8, 2026, 2:36pm

@Ordovician just a thought…

You havent changed your password on the Plusnet member centre have you ?

Its the same password as used for the PPPoE connection. The Plusnet Hub 2, of course, will automatically get the changed credentials using TR069

Ordovician · May 8, 2026, 2:45pm

I haven't changed my password in years; though I probably should! There is no obvious authentication error in the logs, which is typical when a wrong PAP/CHAP password is entered.

Here are some of the message logs:

root@OpenWrt:~# logread | grep -i ppp
Fri May  8 13:49:34 2026 kern.info kernel: [   19.900000] PPP generic driver version 2.4.2
Fri May  8 13:49:34 2026 kern.info kernel: [   20.080000] NET: Registered PF_PPPOX protocol family

root@OpenWrt:~# logread | grep -i lantiq
Fri May  8 13:49:34 2026 kern.info kernel: [    0.600000] 1e100c00.serial: ttyLTQ0 at MMIO 0x1e100c00 (irq = 112, base_baud = 0) is a lantiq,asc
Fri May  8 13:49:34 2026 kern.info kernel: [    5.830000] lantiq,xrx200-net 1e10b308.eth eth0: entered promiscuous mode
Fri May  8 13:49:34 2026 kern.info kernel: [   19.860000] IFXOS, Version 1.7.1 (c) Copyright 2009, Lantiq Deutschland GmbH
Fri May  8 13:49:34 2026 kern.info kernel: [   19.920000] Lantiq (VRX) DSL CPE MEI driver, version 1.5.17.6, (c) 2007-2015 Lantiq Beteiligungs-GmbH & Co. KG
Fri May  8 13:49:34 2026 kern.warn kernel: [   19.960000] Lantiq CPE API Driver version: DSL CPE API V4.17.18.6
Fri May  8 13:49:49 2026 kern.info kernel: [   45.810000] lantiq,xrx200-net 1e10b308.eth eth0: entered allmulticast mode
Fri May  8 13:50:10 2026 kern.info kernel: [   66.930000] Lantiq PTM driver, version 1.0.27, (c) 2001-2013 Lantiq Deutschland GmbH

root@OpenWrt:~# logread | grep -i dsl
Fri May  8 13:49:34 2026 kern.info kernel: [   19.920000] Lantiq (VRX) DSL CPE MEI driver, version 1.5.17.6, (c) 2007-2015 Lantiq Beteiligungs-GmbH & Co. KG
Fri May  8 13:49:34 2026 kern.warn kernel: [   19.960000] Lantiq CPE API Driver version: DSL CPE API V4.17.18.6
Fri May  8 13:49:58 2026 daemon.notice procd: /etc/rc.d/S96led: setting up led dsl
Fri May  8 13:50:10 2026 daemon.notice dsl-notify: Switching to TC-Layer EFM/PTM
Fri May  8 13:50:10 2026 daemon.notice netifd: Interface 'vdsl' is enabled

This suggests that the hardware is working fine.

MisterW · May 8, 2026, 3:29pm

I’m on a Plusnet connection myself and have used Openwrt for a few years now albeit on an FTTP connection so there’s no dsl interface to worry about.

From your logs, it doesnt look like the ppp daemon is starting. My logs show

Fri May  8 11:49:16 2026 kern.info kernel: [   11.879056] PPP generic driver version 2.4.2
Fri May  8 11:49:16 2026 kern.info kernel: [   11.883990] NET: Registered PF_PPPOX protocol family
Fri May  8 11:49:19 2026 daemon.info pppd[2586]: Plugin pppoe.so loaded.
Fri May  8 11:49:19 2026 daemon.info pppd[2586]: PPPoE plugin from pppd 2.5.2
Fri May  8 11:49:19 2026 daemon.notice pppd[2586]: pppd 2.5.2 started by root, uid 0

In my case, I guess the ppp daemon starts as soon as the wan physical link comes up. In your case I guess its waiting for the dsl link to establish ?;:

Could you try the /etc/init.d/dsl_control dslstat command, that should show if the dsl link is up

edit: that

suggests there’s an led configured to show the dsl connection. is that correct and is it on ?

Ordovician · May 8, 2026, 3:46pm

Thanks for the info. I appreciate your help.

dsl_control shows the VDSL engine running, but the link is down with no power:

root@OpenWrt:~# /etc/init.d/dsl_control dslstat
{
        "api_version": "4.17.18.6",
        "firmware_version": "5.7.9.9.0.6",
        "chipset": "Lantiq-VRX200",
        "driver_version": "1.5.17.6",
        "state": "Idle request",
        "up": false,
        "atu_c": {

        },
        "power_state": "L3 - No power",
        "power_state_num": 3,
        "upstream": {

        },
        "downstream": {

        },
        "olr": {
                "downstream": {
                        "bitswap": {
                                "requested": 0,
                                "executed": 0,
                                "rejected": 0,
                                "timeout": 0
                        },
                        "sra": {
                                "requested": 0,
                                "executed": 0,
                                "rejected": 0,
                                "timeout": 0
                        },
                        "sos": {
                                "requested": 0,
                                "executed": 0,
                                "rejected": 0,
                                "timeout": 0
                        }
                },
                "upstream": {
                        "bitswap": {
                                "requested": 0,
                                "executed": 0,
                                "rejected": 0,
                                "timeout": 0
                        },
                        "sra": {
                                "requested": 0,
                                "executed": 0,
                                "rejected": 0,
                                "timeout": 0
                        },
                        "sos": {
                                "requested": 0,
                                "executed": 0,
                                "rejected": 0,
                                "timeout": 0
                        }
                }
        },
        "errors": {
                "near": {

                },
                "far": {

                }
        }
}

root@OpenWrt:~# /etc/init.d/dsl_control info
{
        "dsl_control": {
                "instances": {
                        "instance1": {
                                "running": true,
                                "pid": 2617,
                                "command": [
                                        "/sbin/vdsl_cpe_control",
                                        "-i00_00_00_00_00_00_00_07",
                                        "-n",
                                        "/sbin/dsl_notify.sh",
                                        "-f",
                                        "/tmp/lantiq-vrx200-b.bin",
                                        "-l",
                                        "/tmp/lowlevel.cfg",
                                        "-M2",
                                        "-T2:0x1:0x1_2:0x1:0x1",
                                        "-a",
                                        "/tmp/dsl.scr",
                                        "-A",
                                        "/tmp/dsl.scr"
                                ],
                                "term_timeout": 5
                        }
                },
                "triggers": [
                        [
                                "config.change",
                                [
                                        "if",
                                        [
                                                "eq",
                                                "package",
                                                "network"
                                        ],
                                        [
                                                "run_script",
                                                "/etc/init.d/dsl_control",
                                                "reload"
                                        ]
                                ],
                                1000
                        ]
                ]
        }
}

Ordovician · May 8, 2026, 3:51pm

The LED is working. It repeatedly flashes blue a few times.

MisterW · May 8, 2026, 3:59pm

Happy to help where I can. So it looks like the basic problem is the dsl link is not synching.

I’m a bit out of my comfort zone now, its quite a few years since I had an FTTC connection and I never used Openwrt with it.

IIRC the lantiq chipset was never a very good dsl modem whereas the broadcom chipset in the Hub 2 was much better. Could it be as simple as your line has deteriorated/got noisy and the lantiq just can’t sync ?

Your speeds as shown on the Hub 2 aren’t very good. Which would indicate either a long or poor quality line!. Are those speeds what you typically expect ?

Ordovician · May 8, 2026, 4:07pm

You could be right. Until recently, I was getting close to the advertised 80 Mbps down and 20 Mbps up because I live close (~120 m) to the BT exchange.

These are my current line speeds on the Hub 2:

DSL uptime:0 Days 0 Hrs 25 Mins
Data rate:4.235 Mbps / 18 Mbps
Maximum data rate:4.359 Mbps / 21.818 Mbps
Noise margin:5.7 / 7.3
Line attenuation:42.8 / 50.3
Signal attenuation:46.6 / 50.5

Should I report a line fault to Plusnet/BT?

MisterW · May 8, 2026, 4:28pm

Definitely!. If you were getting close to 80/20 previously then your current speeds are way below your MGALS. Given that the noise margins aren't high , it doesn't look like a capped profile, rather it's a line fault.

Use the Plusnet BOT to report a fault

Ordovician · May 8, 2026, 4:32pm

Thanks. I've marked your response as a solution since its likely a line fault rather than an OpenWRT issue.

MisterW · May 8, 2026, 5:53pm

Yes I’d be pretty sure its a line fault. If you’re on the Plusnet forum , then drop me a pm to let me know how it goes. Username is the same as here.

Ordovician · May 13, 2026, 6:56am

I can confirm that this issue was caused by a line fault. A BT engineer crimped new connections to the telephone line. The connection issue was probably caused by water ingress or fatigue due to old age. Thanks again for the help.