I am a volunteer teacher trying to get my students fired up by learning Broadband. Accordingly I am building a small scale DSL/PPPoE Broadband network that they can touch, deconstruct and put back together themselves with a little help. Issue is, we have very little budget (I am paying for it personally). It needs to be physical to inspire them (we've tried simulation but the eyes glaze over)

So far we have a DSL modem (a DLink flashed with DD-WRT) and an IP DSLAM (ZTE ZXDSL 9806H) connected with a 50 pin amphenol connector.

What we now need is an upstream BRAS and a PPPoE Server. Given budget constraint I was hoping it might be possible to use a ERICSSON T720G MDU ONU (link removed because reputation too low) as the BRAS (doubling as a OLT for a future FTTx demo) for upstream traffic by connecting to the DSLAM on the upstream GPON interface

This would give us the following 'Broadband' architecture as shown in the picture: enter image description here

Will this architecture work? Or do I need to shell out for some more equipment?


There is an error in the diagram. All traffic needs to go via the PPPoE server (Linux or not)

1 Answer 1


I'd remove the Ericsson box. It isn't a BRAS. From your diagram it looks like you'd be using it as a aggregation switch and the Linux PPP Server would be your BRAS.

Personally, for lab purposes I'd also remove the Linux PPP Server and hook the DSLAM up to a Cisco 3825 or 7200 configured as a BRAS. If you really want the Linux element set up a FreeRADIUS server to do AAA for the PPP sessions.

  • 1
    You could use a Mikrotik router as a BRAS as well. They are inexpensive and don't make nearly as much noise.
    – jda
    Mar 2, 2014 at 6:21
  • Thanks Jona, you're a legend! I think Mictrotik is the answer (especially since having a 'Computer as a Router' will overly confuse them). Am I correct in assuming that any H/W supporting RouterOS could be configured as a PPPoE server? In other words, in the interest of cost & lack of traffic, would the RB750 work as a simple PPPoE server? Mar 3, 2014 at 11:08
  • Yes, even the RB750 can move a fair amount of traffic.
    – jda
    Mar 3, 2014 at 17:17

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