Configuring a Copper Mountain DSLAM without wasting IPs?

[akohlsmith]

Plain-jane CopperEdge 24-port SDSL DSLAM. I'm able to set it up such that each SDSL modem in the DSLAM has an IP, but that seems wasteful to me, especially since all those head-end modems have no real need for an IP.

Reading through the documentation, it sounds like it's supposed to be possible to use ProxyArp and have a configuation where I route a block of IPs to the DSLAM's ethernet port IP, and each head-end modem is IP-less, using the IP of the upstream ethernet port.

some ascii-art:

[tt]
router ----- [eth] DSLAM [modems] ------------- [ CPE ]
A B C DEFG
[/tt]

(using private IPs, the real system will use public ones)
A - 192.168.1.1/28 and 192.168.1.33/28
B - 192.168.1.2/28
C - (no ips)
DEFG - 192.168.1.34 through .58/28

eg. customer D has an IP of 192.168.1.34/28 and a gw of 192.168.1.33. The head-end modem at C has no need for an IP in this case, and I don't waste an IP for every customer's head end modem.

I'm not interested in PPPoE at all, my customers prefer straight IP routing (as do I).

Has anyone configured one of these beasts as described?

 

[CrashTestDummy]

The big questions are;

1. What WAN card do you have installed?
2. What SCM/BCM combination are you running?
3. What net model are you using and for what cpe?

We have set up several types of CPE using HDIA and CopperVPN netmods using grey IPs and allowing the upstream router to NAT it all out. We have done this with 192 users (both voice and data) with the SCM/BCM2 and DS3 WAN combination on a 5.20.21 chassis.

 

[akohlsmith]

We don't use a WAN card (our uplink is ethernet straight to the router).

SCM HW version is 1.0, 5.0.94 (PROM 2.10.45).
BCM is HW 1.0, 5.0.94 (PROM 1.40.18).

CPE is varied... SpeedStream 5250s, Xpeed x320 and x310s and even some PairGain Megabit Modem 300Ses (not sure if those are going to work though).

I was avoiding gray (private) IP space because I was fearful that the windows clients would have issues. I know they can do ptp but I'm really trying to get this as "clean" as possible.