Instructions for UK ISP VDSL settings don't match options available in LuCI

Installing and Using OpenWrt Network and Wireless Configuration
1

I'm following the VDSL configuration guide for common UK ISPs here for this all-in-one BT Homehub v5a modem router using OpenWRT 24.10.0.

Under the For VDSL (FTTC) steps, step 3 says -

Edit the 'WAN' interface → Physical Settings tab.

which is where things go wrong; editing the WAN interface brings up settings under 4 new tabs (General Settings, Advanced Settings, Firewall Settings, and DHCP Server), none of which show any mention of 'Physical Settings' or 'Custom Interface' that the guide goes on to mention in step #4.

I wondered: Might these instructions be for a different, older set of settings shown in LuCI ... or am I just failing to correctly follow the these steps? (If I can figure out how to embed images, I can show what my Network > Interfaces > wan > Edit screen shows).

(If these steps are out-of-date, how should they be updated for 24.10.x?)

In preparation for switching over to a new ISP, I asked them for a heads up on what settings I'd be expected to use and they came back with -

ISP - Other
VLAN - Enabled
VLAN Tag / ID - 101
Connection Type - PPPoE

and since I'm a newbie regarding OpenWRT and most networking stuff, where VLAN Tag doesn't mean anything to me and doesn't appear to have any corresponding field to set in the wan interface settings shown to me in LuCI, I thought I'd better take this opportunity to also ask if those For VDSL setup steps #1 to #4 (assuming I can eventually find some 'custom interface' field to set to 'dls0.101'?) and the For most ISPs ... steps #1 to #3 should be all that's needed to work with the settings mentioned by my future ISP shown above?

2

UK configs for pasting directly into the /etc/config/network file - https://openwrt.org/docs/guide-user/network/wan/isp-configurations#united_kingdom.

3

On the first edit wan page, pull down the Device list and scroll to the bottom. Click and type dsl0.101 where it says Custom. Then press enter. The change will not be added if you just click away.

4

Thanks very much for the replies. From them, I think it's fair to conclude that those configuration example steps are out-of-date and would benefit future users from being updated in a couple of ways -

  1. The instructions to Set 'DSL' parameters to 'Annex A + L + M(all)' is not available; the closest match is one saying ADSL (all variants) Annex A/L/M + VDSL2 Annex A/B/C, which I assume is now what I should use.
  2. The instruction from @mk24 above, for setting dsl0.101, is now something I'm able to follow and so should replace Edit the 'WAN' interface → Physical Settings tab and Select 'Custom Interface' and enter 'ptm0.101' or dsl0.101 ... instructions.

Regarding the option/work-around of using the /etc/config/network ISP settings listings, my new ISP (OneStream) isn't listed among them so if/when I can successfully switch over, it might be helpful to others if I can add a note for which one (if any are) suitable. Is that something I can do or should I just report back here and hope that someone else can update those listings with a note about what works for OneStream?

After going through the (tweaked) 'United Kingdom - Quick Setup with LuCI' steps, I looked at the contents of my resultant /etc/config/network file to see how it compares with the settings in some of the UK ISP config listings. There are a few notable differences. The quick setup guide says I should expect to end up with something like -

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

config interface 'wan'
        option ifname 'dsl0.101'
        option proto 'pppoe'
        option username 'YOURUSERNAMEHERE'
        option password 'YOURPASSWORDHERE'

and my config dsl 'dsl' section matches exactly. My config interface 'wan' looks like -

config interface 'wan'                                                                                                                 
        option device 'dsl0.101'                                                                                                       
        option proto 'pppoe'                                                                                                           
        option username 'username'                                                                                                     
        option password 'password'                                                                                                     
        option ipv6 '1'

... I.e. I don't have a option ifname but have a similar looking option device. Is this equivalent or is a reference to another config device block elsewhere in the settings file, like these others that I have in there? -

config device                                                                                                                          
        option name 'lan1'
        option macaddr '...'

config device                                                                                                                          
        option name 'lan2'
        option macaddr ...
...
config device                                                                                                                          
        option name 'dsl0'                                                                                                             
        option macaddr ...

... but I don't see a -

config device                                                                                                                          
        option name 'dsl0.101'
        option macaddr ...

So I'm wondering if I'm missing a step to create some named config device ... option name 'dsl0.101' ... device that's now reference by my 'wan' interface settings, or whether I've ended up with newer settings where option device ... is simply a new synonym for an old option ifname ....

.. And if I've nothing to worry about here, then perhaps the quick setup guide could benefit future users by updating the section that illustrates the /etc/config/network, just after where it says ...should look like this when you're done configuring... to now reflect use of option device 'dsl0.101' instead of option ifname 'dsl0.101'.

Thanks again for all the help.

5

TLDR: The setup guide and config file examples I've referenced look to be out-of-date and perhaps not applicable/correct for more recent versions of OpenWRT, leaving new users - particularly newbies like me - in for a great deal of trouble.

The more I look at things, the more questions and concerns I have about the state of the current ISP configuration guide notes, which look to be out-of-date. If I can get some answers/advice, I'd be happy to try to update the guide.

I will try to list the issues I have so far -

  1. The advice from @mk24 to simply type in dsl0.101 in the wan general settings 'Device' drop-down list adds option device 'dsl0.101' to the network config file, under 'wan'. This is different from the example UK ISP config listings, which all show option ifname 'dsl0.101. I think this is significant. I think most/all of the example network config settings come from older OpenWRT versions, which raises the question of what terminology/compatibility differences are there between the older config file settings and those for the lastest version?

I would assume the file settings generated through making LuCI config changes would be the most up-to-date and correct settings to use... But then, since those appear to be different from what we see in the (older?) example UK ISP config settings, how appropriate is the advice from @frollic to simply copy example settings directly to my /etc/config/network file?

  1. As I already mentioned earlier, the setup guide for this router says, to set the DSL annex setting to "Annex A + L + M(all)" and there isn't an exact match in the options for this doing so. The closest matching option ("ADSL (all variants) Annex A/L/M + VDSL2 Annex A/B/C") through the LuCI U.I. creates the setting option annex 'a'. However, this is different from absolutely every instance of the option annex ... field in the ISP settings file examples, all which are in the form, option annex 'b'. So again, is the UI's wording of the ...A/L/M... option the definitive true setting or is the config file's option 'b' the definitive setting, regardless of what it maps to (correctly or incorrectly?) in the UI?

I.e. Is it the case that somewhere prior to OpenWRT 24.10.X, the Annex A/L/M used to correspond with the network setting file value option annex 'b' but in more recent versions this option now corresponds with option annex 'a' in the config file? ... OR is the the network config file value of annex 'b' truly the setting that needs to be used, regardless of what OpenWRT version I'm using (and what the UI drop-down shows) and therefore the guide/wiki is now wrong in saying I should select the Annex A + L + M option and now, instead, should choose ADSL (all variants) Annex B + VDSL2 Annex A/B/C... which now maps to option annex 'b'?

  1. Elsewhere in the UK ISP example network file settings listings, it has a section that says For 22.03.X/23.X builds and then shows -
...
config device
	option name 'dsl0.101'
	option type '8021q'
	option ifname 'dsl0'
	option vid '101'

config interface 'wan'
	option device 'dsl0.101'
	option proto 'pppoe'
	...
...

The use of device 'dsl0.101' here, which is what I get when following @mk24 's instruction above, instead of ifname 'dsl0.101' that's commonly used throughout the rest of the examples, makes me think -

  • These settings should probably also apply to me and that the guide/wiki should instead say, "For 22.03.X/23.X and newer builds".
  • It looks like I may have been right to question whether that instruction to simply type dsl0.101 would have been sufficient; it looks like option device 'dsl0.101' is a reference to a config device setting block that should be elsewhere in the network file... which isn't there from following the guide's steps.
  • My suspicion is that before typing dsl0.101 in the wan device drop-down, I first need to have created this dsl0.101 named device, along with finding a way to correctly give it a VLAN ID of 101... But again, given how network file syntax changes may occur between OpenWRT versions (like we've already seen, going from use of option ifname 'dsl0.101' to now using option device 'dsl0.101' + config device ... option name dsl0.101'... [and also possibly annex 'b' becoming annex 'a'?]), would it be better to instruct users to create these settings through the UI or though entering values into their network config file?

It looks to me like we can (and should) create this new dsl0.101-named device, under Network > Devices > 'Add device configuration'.

This then gives me a load of options, for which I have no guidance so could use some help in figuring out the most correct, up-to-date settings. The 'General device options' are -

  • Device type: I suspect VLAN (8021.q) is the one to go with here.
  • Base device: Don't know; I'd guess wan.
  • VLAN ID: I'm pretty sure 101 is what to go with here, since that's one of the few things my future ISP explicitly specified.
  • Device name: dsl0.101 at a guess.
  • And there are a bunch of other fields (MTU, TX queue length, enable IPv6, IPv6 MTU, DAD transmits) that have defaults in, which I'd be tempted to leave at their defaults ... unless someone here advises otherwise.
  • There's also a load of settings in the 'Advanced device options' tab (Ingress QoS mapping, Egress QoS mapping, Enable promiscuous mode, Reverse path filter, Accept local, Sent ICMP redirects, Honor gratuitous ARP, Drop gratuitous ARP, Neighbour cache ... etc), which I'd leave empty/automatic/default ... unless someone advises otherwise.

I think it'd be nicer (maybe better) to provide the LuCI steps to set this up properly, at least on this United Kingdom - Quick Setup with LuCi guide page and I'd be happy to have a go at updating it (assuming my switch-over all works with whatever settings I end up with)... providing I can get some guidance on everything here.

  1. Because the example ISP configs has a section, "For 22.03.X/23.X builds", which looks closer to settings I get through the more recent 24.10.0 LuCI, along with explicitly setting VLAN 101 settings, I wondered, should I also be ensuring I copy the other blocks shown in that section of config file too, including -
config atm-bridge 'atm'
	option vpi '0'
	option vci '38'
	option encaps 'vc'
	option payload 'bridged'
	option nameprefix 'dsl'

which, along with me not knowing what it means, I don't have in my /etc/config/network file and also -

config interface 'wan6'
        option proto 'dhcpv6'
        option reqaddress 'try'
        option reqprefix 'auto'
        option ifname 'dsl0.101'

?

6

option ifname has been deprecated for some time.

Devices already named in the kernel such as the eth ports do not need a config device section. The dot notation can be used to place a VLAN on an eth-like device without previously declaring the VLAN.

On some routers the kernel does not know how to obtain the Ethernet "factory" MAC address from flash so the firstboot scripts extract the factory MAC and create config device sections to set up the MAC.

7

This is the same option as before, just the description has changed to make it clear that it also enables VDSL2 support (because all the other options except the first three are ADSL only). It is very likely the right choice for a connection in the UK.

8

I think I didn't explain my confusion very well: The wording of the UK LuCI quick setup says, "Set 'DSL' parameters to 'Annex A + L + M(all)' ..." (which, we're agreed is now called " ADSL (all variants) Annex A/L/M + VDSL2 Annex A/B/C"). This produces option annex 'a' in the config file.
Fine.
... However, ALL the example VDSL ISP configs use option annex 'b'... not 'a'.
So that raises the question, "Why does the quick setup For VDSL(FTTC:) steps specifically say to select an annex mode that produces a setting that's different from all the example configs?"

9

Possibly related, both ADSL and VDSL2 standards have an Annex A and B, albeit for different things... IIRC
For ADSL Annex A, B and J define whether or not to spare out the initial subcarriers to allow coexistence with POTS, IDSN, of no coexistence.
For VDSL2 Annex A collects the Bandplans for Northamerica/USA, Annex B the band plans for Europe and Annex C for Japan IIRC (not sure what the rest of the world is supposed to use).
In VDSL2 nomenclature the ADSL Annex A, B, J define bandplans... especially older ADSL modems are likely to have fixed frequency filters for either Annex A or Annex B and hence can be probematic if used with the wring Annex, but for VDSL2 modems that IIRC ist not the case anymore. But you still need to configure the right Annex (even though the one bandplan in Annex A should mostly work in Europe as well).

10

I don't know why the example configurations are like that.

If line_mode is set to "vdsl", then the value of the annex option shouldn't matter, as long as it is one of "a", "b", or "j". In that case, the only effect of the annex option is which firmware is loaded it is not specified explicitly in the config.

Previously, I thought that on VR9 modems, the DSL firmware annex determines the supported carrier set (tone option), so it would have to match. But I just tested that again, and that is actually not the case. The config just seems to be a bit sticky, and a reboot can be required to apply it fully.

Still, combining option annex 'b' with option tone 'a' (i.e. carrier sets A43C + J43 + A43) is a bit strange, because typically the used carrier set matches the ADSL Annex.

The only other possible reason for using option annex 'b', which I can think of, would be if you have an Annex B device: When line_modeis not set tovdsl`, only a DSL firmware which matches the hardware can be used.

11

I just wanted to say thanks to all who helped with replies.

I've made a couple of updates and additions to the wiki and network config ISP listings to clarify and update slightly out-of-date steps/terminology as well as add the network config settings that work for my new, previously unlisted ISP.