Multilink PPP using VLANs, two 1.5 meg DSL modems?

  • I am trying to figure out how to set up Multilink PPP on two 1.5 megabit DSL modems, for 3 megabit combined bandwidth. We're in a rural area where 1.5 meg is the max speed available on a single copper pair regardless of distance.

    (It's not entirely clear if my ISP CenturyLink even supports multilink PPP, but it's been suggested to me to just try it and see if it will work. They do offer it in some areas. If they don't support it here, I can still use pfSense to just load balance across the two DSL lines.)

    Apparently the existing documentation skips over some setup details.

    Part of the challenge is that the initial pfSense setup creates WAN and LAN interfaces and auto configures them. But the autoconfigured WAN interface created during initial setup isn't actually going to be used, since it is going to be changed to a PPP multilink pool later.

    So it looks like none of the DSL modem ethernet interfaces should be assigned to the WAN initially, as this can get in the way of creating the multilink pool. Instead, I need to make up a fake port that doesn't exist and assign the WAN to that, just to satisfy the initial setup.

    As part of this setup, I am using an external NetGear GS105E ProSafe 5-port gigabit switch (currently the cheapest VLAN-capable switch on NewEgg). While creating the initial pfSense VLANs for the switch, I am temporarily faking the WAN connection by assigning it to a VLAN ID that doesn't exist and won't be used.

    NetGear GS105E, Easy 802.1Q VLAN config:

    • Port 1 - VLAN: 1

    • Port 2 - VLAN: 2

    • Port 3 - VLAN: 3

    • Port 4 - VLAN: 4

    • Port 5 - VLAN: ALL

    pfsense 2.01 initial install:

    • Will you be using VLANs? Yes

    • create -> em0 -> VLAN 1

    • create -> em0 -> VLAN 2

    • create -> em0 -> VLAN 3

    • create -> em0 -> VLAN 4

    • create -> em0 -> VLAN 5 (no assigned ports)

    Assign interfaces:

    • WAN -> em0_vlan5

    • LAN -> em0_vlan4

    • OPT1 -> em0_vlan1

    • OPT2 -> em0_vlan2

    • OPT3 -> em0_vlan3

    Web GUI setup:

    Skip the wizard, click on logo

    Interfaces -> OPT1

    • Enable

    • Rename to DSL_LINE1

    • Type: None

    Interfaces -> OPT2

    • Enable

    • Rename to DSL_LINE2

    • Type: None

    Interfaces -> (Assign) -> PPPs -> Add

    • Link Type: PPPoE

    • Interfaces: DSL_LINE1, DSL_LINE2

    • PPP username / password

    Interfaces -> (Assign) -> Interface Assignments -> WAN

    • Change network port to: PPPOE0(opt1,opt2)

    Reboot pfSense

    At this point it looks like the Multilink PPP setup should be done, and it should Just Work. Is this correct?

    The modems I intend to use are basic "TP-LINK TD-8616 ADSL2+"  with no internal routing capabilities.

    Apparently, nothing needs to be done with the DSL modems or the assigned pfsense interfaces?

    No IP address assignments or anything is needed on them, just plug the modems into Switch port 1 and port 2 and PPPoE will automatically handle the rest?


  • Centurylink does this on VDSL but not ADSL.

    If you can get one of the local ISP's to do it then you can get it as Ive done at a remote site we have.

    Olypen is our ISP in case your near Washington State.

    it looks like none of the DSL modem ethernet interfaces should be assigned to the WAN initially

    Correct.  You assign the pppoe interface to WAN.

    http://pfsense Ip/interfaces_ppps.php    Create a ppp.  Choose two or more interfaces.  Set your credentials here.   (not opt1 and 2 but actual interfaces)  You  dont need interfaces assigned past this.

    http://pfsense Ip/interfaces_assign.php   Set your WAN to your new pppoe interface.  Pretty much that easy.

    Modems must be in bridge mode.

  • FYI, the PPP interfaces list does not show any raw device ports for my VLANs. The only choices are:

    em0 (xx:xx:xx:xx:xx:xx)
    OPT1 (renamed DSL_LINE1)
    OPT2 (renamed DSL_LINE2)

    However, it turns out that this does not matter. After getting it all hooked up tonight as documented in my first post, PPP works properly with OPT1 / OPT2 selected

    I do not yet have the second DSL line installed (these are preparations for arrival). But I can tell that multilink PPP is working because I can unplug the one phone line from one DSL modem, plug into the other modem, and after a few seconds the Internet is accessible again via pfSense.

    It doesn't matter if one modem or the other is left disconnected and powered, the link works anyway with either one. So woohoo, multilink PPP has failover capability too.

  • Just because you can get a connection from either line doesn't prove that you can get it yet. remember that the provider does have to support it.  For ADSL Centurylink does not. And if they did they would have to turn it on for you. You need to call and ask.

    I wouldn't get my hopes up just yet.

    I have Century Link for my DSL and have to use another ISP (that I talked into doing mlppp) to provide service for me.

    Good Luck!

  • I also recommend Olypen if you're in Washington state,  i have two dsl lines also with mlppp.