PPPoE poor throughput
I just got a new ADSL2+ line installed. I'm using a Draytek Vigor 120 to bridge PPPoA to PPPoE and doing the ISP login on the pfsense box.
Testing with the ISP supplied router (Huawei HG533) I see over 10Mbps of downstream throughput.
Switching to the draytek + pfsense, I'm seeing much less (about 5 to 6Mbps). Upstream is the same in either case (about 0.6Mbps) and ping is also similar with both configurations.
The draytek is reporting a sync speed that would be consistent with the 10+ MBps of throughput numbers rather than the lower throughput I'm seeing with pfsense. It's syncing at about 13Mbps, with 12db of SNRM and ~30db line attenuation, only very small numbers of CRC errors are being reported by the modem.
I haven't yet tried doing a PPPoE login from a PC via the draytek to see if the modem might be the problem, but I actually lean more towards suspecting pfsense, so I thought I'd post here first to see if anyone could suggest what to try.
Throughput between LAN segments is fine (hundreds of Mbps).
I've ensured the MTU is set correctly (1432 as specified by my ISP, and what was set on their supplied router). I've also tried MSS clamping set to 1432.
I've tried using "fetch" directly on the pfsense box, using a known fast source site to download a big file.
Check the interface between pfSense and your modem. Perhaps it is 10Mbps or perhaps there is a mismatch (one end in full duplex, the other in half duplex). Check the counters of the two interfaces; perhaps one end is seeing lots of errors.
Hi thanks for the reply.
I did check that, but thanks anyway.
I've fixed the problem now.
In case someone else finds this thread and is having trouble with a Draytek Vigor 120 and low throughput, here's what happened:
- I used a PC to make the PPPoE connection to eliminate the pfsense box from the equation, throughput was still poor.
- So it's the modem.
- Reflashed the firmware and reset to defaults on the modem, still no improvement.
Much scratching of the head later, while switching back and forth from my ISP supplied router to the Draytek Vigor 120, I accidentally plugged the Vigor 120, which takes a 9v DC power supply, into the supply for the Huawei HG533 my ISP has supplied, which is 12v 1A. Throughput went up to 10+ Mbps.
Turns out I have an earlier Vigor 120 v2 which some googling reveals had a weak PSU. I'm going to leave it on the 12v supply for now, since if it hasn't killed the modem immediately, I doubt it will. I will contact Draytek for a later model PSU that supplies up to 1A at the required 9v DC.
I'm not recommending anyone that has a Vigor 120 just sticks 12v into it, you could easily kill it I imagine, and I wouldn't have done it on purpose, but it does seem to be coping OK. A better 9v supply capable of delivering 1A is the ticket.
Ah, that's some useful info. Seems like I've been seeing similar things in a number of unrelated products recently, I guess manufactures like to cut costs wherever they can.
Are you aware that Draytek released a number of different firmwares for that modem? They are apparently tuned for different line conditions though I never found any documentation. I experimented with a number of them, and throughput did vary, when I was having stability issues. Perhaps I just had a bad psu.
Thanks for the reply. Yes, I'm aware of the different modem codes available, I was on 332201_A the recommended one for the UK.
Unfortunately, the low throughput came back again with the 12v PSU, so I did try reflashing to 321311_A which is recommended normally for poor lines, mine is a good line but I thought it was worth a try anyway, but it made no difference. When I've tried different modem codes before on other lines, the difference has usually been fairly minor - worth doing (perhaps 10%), but not a massive difference, so I haven't tried any other codes as I don't expect that to be the problem.
I've gone back to the 9v 500ma PSU to ensure I don't kill the Vigor 120 and have contacted Draytek asking them to replace the whole thing. I do think the bad PSU is quite likely the cause - I suspect the reason the problem has come back later with the 12v supply is that the modem seemed to be running hotter (as could be expected) on 12v, so I got the full potential of the line at first, then after a while I think a processor inside the Vigor 120 has throttled to prevent overheating, reducing throughput. A bit of a wild guess, but it's the best I can do.
I'll update the thread once I've got a replacement to confirm if it's fixed the problem.