LEDE device as ADSL bridged modem

Hello,

as this is my first post on LEDE forum I would like to say hello :slight_smile:

I bought Netgear DM200 and tried to use it as ADSL modem connected to other xDSL router (without ADSL modem builtin). Unfortunately, on stock firmware, when modem is switched to modem-only mode (which is supposed to be bridge I think) I can not set very important settings like: VPI, VCI or even if this is ADSL or maybe VDSL connection. So as there is LEDE snapshot build for this device I decided to give it a try.

I installed LEDE from snapshot and was able to log in over ssh. It gets synchronized but I am unable to configure it to act as modem in bridged mode.

Here is my config:

config interface 'loopback'
        option ifname 'lo'
        option proto 'static'
        option ipaddr '127.0.0.1'
        option netmask '255.0.0.0'

config globals 'globals'
        option ula_prefix 'XX:XX:XX:XX:XX:XX::/48'

config atm-bridge 'atm'
        option vpi '0'
        option vci '35'
        option encaps 'llc'
        option payload 'bridged'
        option nameprefix 'dsl'

config dsl 'dsl'
        option annex 'a'
        option xfer_mode 'atm'
        option line_mode 'adsl'

config interface 'lan'
        option type 'bridge'
        option ifname 'eth0'
        option proto 'static'
        option ipaddr '192.168.1.1'
        option netmask '255.255.255.0'
        option ip6assign '60'

config device 'lan_dev'
        option name 'eth0'
        option macaddr 'XX:XX:XX:XX:XX:XX'

config interface 'wan'
        option ifname 'dsl0'
        option proto 'pppoe'
        option username 'username'
        option password 'password'
        option ipv6 '1'

config device 'wan_dev'
        option name 'dsl0'
        option macaddr 'XX:XX:XX:XX:XX:XX'
config interface 'wan6'
        option ifname '@wan'
        option proto 'dhcpv6'

config interface 'wan' is I think irrelevant but I did not remove it.
I tried to use information from this thread [SOLVED] Turning a Xdsl lede router functionally into a bridged vdsl-modem but without luck.

I tried to use it directly connected to PC over Ethernet but also no luck. I even isntalled LUCI but LEDE UI us a but more complex than some stock ones and I did not find easy way to set this bridge. Of course there is ADSL bridge section in Interfaces but it was already filled up with what I set in config file.

Anyone tried to use LEDE powered device as such modem?
One more thing: when I use some spare ADSL modem in bridge mode router is able to connect to internet over PPPoE, sam as PC directly connected to it, so problem is for sure in configuration.

Thanks in advance for any help

OpenWRT has relatively poor support for xDSL modems, because of the absence of open source modem drivers.

See if any of this is helpful:
https://wiki.openwrt.org/doc/hardware/xdsl
https://openwrt.org/toh/netgear/dm200

LP,
Jure

I, too, am a first time poster, and am also struggling with properly configuring my Netgear DM200 for full bridge mode (I would also like to know how to do half bridge just so that's an option.) I'm bumping this thread in the hopes anyone has any ideas, as I'd prefer not to have to rollback to Netgear's cruddy stock firmware. I loathe Netgear in general but couldn't find another standalone VDSL modem, and since this one is commonly available and widely supported by most ISPs I figured what the hell.

I'm running version 18.06.0, the latest firmware available as of the date of this post.

Thanks in advance!

No advantage in using Openwrt as bridged modem

Most the guides talk about configuring the OEM firmware to bridged mode. Since no advantage in Openwrt firmware when you are in bridge mode it is just passes thru traffic

I checked the user manual for the DM200

Page 69 of the manual is what you need to read (Disable the Modem’ s Routing Features and Use the Modem as a DSL Modem Only).

fwiw, refer to section 9.8 of lede install guide for HH5a. VDSL Bridge mode works fine on HH5a and Openreach ECI modems running 17.01.4. I've also tested 18.06.0-rc1 on the ECI modem.
https://openwrt.ebilan.co.uk/viewtopic.php?f=7&t=266

Update: Not suitable for DM200 which only has one LAN port. See posts below.

1 Like

No biggie, but I like the ability to ssh into my bridge-mode HH5a and get statistics vie the terminal, also the ability to install helpful tools like ethtool, iftop, nano and even midnight commander is nice to have...

Best Regards

Is there a good user guide on openwrt.org ?
Or
Is a luci package available ?

The question is asked often so there is a need for it.

First, full disclosure - I'm an OpenWRT noob; DD-WRT is my favorite firmware, which is what I'm running currently on a Buffalo WBMR-HP-G300H (currently the ONLY compatible combo unit) and now on a Linksys WRT3200ACM, which is replacing the Buffalo unit due to the Buffalo only supporting ADSL2+ (I'm being upgraded to VDSL2 in the next couple of months) and N-Wireless as opposed to AC. Also, the Linksys is a MUCH more robust unit in general due to being a newer model. Unfortunately, it's only a router, hence why I need a separate VDSL2 modem. DD-WRT isn't available for the Netgear DM200, and frankly ANY open source firmware is better than ANY stock firmware - ESPECIALLY Netgear's.

Additionally, I want the DM200 to switch seamlessly between an ADSL2+ connection and a VDSL2 connection, and it doesn't seem as if the stock firmware will, whereas OpenWRT has an "auto" setting. I relocate frequently and want everything set up so I just plug it in and it works. I expect a backwards compatible device to be capable of this. It seems as if you have to change the configuration even if it's in bridge mode with stock firmware, though if anyone else has more experience with this unit and can tell me otherwise then great.

So yes, there ARE advantages of running third party firmware even when using the device in bridge mode.

Interesting manual, but there's a few issues with it when trying to apply the instructions to a DM200. First, the manual assumes a 4 LAN/1 WAN/1 DSL port device. As the DM200 is only one DSL port and one LAN port, some common sense adjustments need to be made when regarding the given instructions. It seems that in general you're creating a WAN BRIDGE interface from the DSL port to the LAN port; that much I took away from it. With the DM200, once this is done with the ONLY LAN port, you lose access to the configuration interface and have to reset the device completely to access it again. I would be okay with this, however the issue I'm running into is the modem won't revert the changes successfully and give me the option to "apply unchecked", meaning the device changes the LAN port back to static functionality when rebooted. Attempting a power cycle while on the same screen, and logging back in on another tab, results in a "Forbidden" error when attempting to "apply unchecked". I also tried unplugging the modem before the 30 second cycle was complete, which appeared to work, yet it didn't function correctly once plugged into my router. There also doesn't seem to be an option to save the settings without applying them, and subsequently rebooting the device without losing the configuration changes.

Basically at this point I'm at a loss, and I consider myself pretty tech savvy in general. It seems as if I will have to revert to stock firmware on this device in order to use it as a full bridge. And buying another standalone VDSL2 modem doesn't even seem to be an option... I'm surprised these are so few and far between.

Thank you for pointing out the DM200 only has one LAN port. That indeed would pose a big problem when trying to configure the DM200 using LuCI as the instructions assume there are at least two ethernet ports.

The only workaround I can think of would be to configure/manage via the serial interface and/or SSH which is more difficult and less convenient. Perhaps edit the configuration files on a computer then perform a one-time upload of these settings to the modem. Any changes only become effective when you reboot the modem. Then use serial interface to subsequently edit any settings.

Someone may correct me if I'm wrong, but with regards to the 'auto switching' between VDSL and ADSL. I don't think it will actually work in practise. For example, in the same 'DSL' section in LuCI, you may observe there is no 'auto' option for 'Encapsulation mode'. ie. VDSL usually uses PTM and ADSL uses ATM. Similarly, VDSL connections require the ifname (VLAN tag) to be set to 'dsl0.xxx', and for ADSL, the ifname would be just 'dsl0' when using OpenWRT 18.06.

TPlink TD-W9970 is an inexpensive VDSL router with VDSL bridge mode option costing similar to the DM200, but I presume it is not available in your location. TD-W9970 can't run OpenWRT.

(Correction. I incorrectly quoted more expensive TD-W9980, which as pointed out by @takimata can run OpenWRT)

If the DD-WRT firmware on your Linksys WRT3200ACM router supports VLAN tagging, I would suggest to set up a VLAN trunk between the DM200 and the router. One VLAN carries the bridged DSL, another VLAN provides access to the configuration interface of the DM200. And if it doesn't support VLANs, replace DD-WRT with OpenWrt. :wink:

Start with VLAN 1 for the configuration interface. On the DM200, change the LAN physical device from eth0 to eth0.1, disable the DHCP server and give LAN an IP address different from the router, but still within the LAN address range. On the WRT3200ACM, look up the WAN physical interface. Let's assume it is eth0. Now set up the LAN interface as bridged (should be the default) and add the physical interface eth0.1 to the bridge while keeping the other physical interface (e.g. eth1.5) that's already there. I based this guide on OpenWrt, you may have to adapt it a bit for DD-WRT.

Once you've got this working, add VLAN 2 to carry the bridged DSL traffic. On the DM200, create a WAN bridge between dsl0.xxx and eth0.2, where xxx is the VLAN ID used by your ISP. On the WRT3200ACM, change the WAN physical interface from eth0 to eth0.2.

Let us know if you have any questions. There is also some VLAN documentation in the OpenWrt Wiki.

It's no big deal that there isn't an additional WAN port on the DM200... again, I WANTED a standalone modem. It just means once the settings are configured properly it has to be completely reset before accessing the configuration interface again. I can live with that provided I can actually get it configured correctly.

I had another go at it, this time configuring the LAN settings and saving WITHOUT applying, then configuring the WAN BRIDGE. I was able to successfully "apply unchecked" when going about it in this manner. This indicates a possible bug in the firmware that the OpenWRT developers may want to look into, so hopefully this gets back to whoever it may concern.

That said, it STILL doesn't work. It looked like it tried to sync but with no success. I'm guessing you're right about not being able to autosense the type of connection. I might try manually specifying an ADSL connection to see what happens. Worst case scenario I'll ALWAYS have at least one ADSL modem on hand (ESPECIALLY the Buffalo unit since they're nearly impossible to obtain anymore, and I'm a stickler for keeping spare networking equipment handy) so once I actually DO have VDSL service I can reconfigure the DM200 and leave it as such and swap the equipment entirely if it becomes necessary to revert to an ADSL connection (hopefully there won't be any left in Australia within the next couple of years or so given the NBN is over 50% complete.)

I DO have a D-Link DSL-2877AL I COULD use... it just means I bought the Netgear for nothing. I WOULD use the D-Link as my actual router IF a) it supported DD-WRT and b) it had Gigabit Ethernet LAN ports (seriously Gigabit WAN and 10/100 LAN... who designs a product like that?!?!)

1 Like

Thanks for those instructions... if those settings are necessary I can certainly apply them. My feeling is that once you have a properly configured DSL modem bridge, it's just a question of configuring the PPPoE settings on the router and it should just work (or a half bridge in which case I could configure the router for DHCP and swap for an HFC cable modem or FTTP connection without reconfiguring the router.) The fact that it's not working means the modem is not configured correctly. If necessary I've got a couple of known working standalone ADSL modems I can use to test the router configuration if I need to, though given the LED wasn't indicating I had DSL sync I doubt the router is the problem.)

Mainly I just want to get to the point where my Linksys WRT3200ACM becomes my actual router. That unit is high end enough that I shouldn't need to swap it for a while. I've had the Buffalo unit in service for over six years and would continue to use it if it weren't for the fact that the modem only supports ADSL2+, besides it's time for AC wireless so I would have had to retire that unit one way or another. I would have retired it sooner had I actually had access to the NBN by now... literally every other address I've lived at was upgraded AFTER I moved out and the address I'm living in now is "in progress". Ugh...

Of course OpenWRT, or ANY custom firmware, for that matter, isn't available for the D-Link DSL-2877AL. I'd be better off reverting the Netgear DM200 to stock firmware and configuring it as a bridge the easy way.

I'll try it one more time with OpenWRT, this time with manual settings for an ADSL connection. Fingers crossed...

The configuration I proposed is untested, but I did my best to give a working example. I wouldn't describe it as "necessary", but very useful. It allows you to keep access to the DM200's web interface even when the device is set up as a DSL bridge. You can then switch between ADSL and VDSL, enable/disable VLAN tagging towards the ISP, and investigate any issues, all of this without having to reset the device each time.

It helps to ACTUALLY read posts properly BEFORE commenting. Oops.. my bad. I understand the reason for VLAN tagging now.

I'm not fussy about having access to the configuration interface once the modem is configured properly. I basically WANT it to function as a "dumb" bridge. I'm happy to push the reset button if necessary to make changes. Though VLAN tagging certainly is a good solution for those that absolutely need to have their cake and eat it too. And yes, DD-WRT supports it.

I was thinking the other solution is to open the unit for access to the serial connection and thread the wire in such a way that it could fit through one of the ventilation holes and wire accordingly to an RJ45 port, then I could just use a Cisco serial cable to a Serial to USB adapter to gain access that way. Might be an interesting side project...

Be careful
The cisco serial cable is rs232
The modem serial is TTL

They are different voltages , will cause damage

1 Like

I learn something new every day. That said, would it necessarily matter so long as the pinouts are correct? The cable itself doesn't have anything to do with voltage?

I could use an RS-232 cable... just thought it would be neater to have a "Cisco" service port on the Netgear.

Cable it self is just copper.
Just don't connect it to an rs232 port.

https://openwrt.org/docs/techref/hardware/port.serial

As long as your serial to USB adaptor is TTL 3.3V