ADLS2+ speed worse than ADSL2 with 7800N

Hi,

I have replaced an old modem happily chundering on ADLS2 whith 7800N to take advantage of 2+ (and rationalise other networking bits - switches, APs, IPV6, etc.) However the 2+ performance is terrible compared to 2 with the 7800N. Downloading a 1.2MB file over ftp gave ~700KB/s on ADSL2 (same as my old modem) and only 7KB/s with ADSL2+ which lots of stalls.

All I need to do to change performance is to toggle 2+ from the ADSL op mode modulator list and resync, all other router settings are the same. The ADSL status shows no problems and gives a downstream value of ~12000 with ADSL2+, only 9655 with ADSL2.

FTR the line stats are:
SNR Margin(Upstream) 6.5
SNR Margin(Downstream) 3.2
Line Attenuation(Upstream) 20.3
Line Attenuation(Downstream) 29.0

I also turned off Annex M mode even though I don't have it. Firmware is 1.06e. The WAN status page shows no errors or drops with either 2 or 2+

Where to go with this? Since it is my own modem, not the ISP's (PlusNET) I assume they will say the down/up-stream numbers look good from their end. Or is it possibly an exchange issue they can chase up? Or chase up with Billion as a firmware issue? Or some cunning router setting I have missed?

TTFN

Mile

Any idea what chipset the exchange is using? I have a 7800 and have a support request open with Billion for pauses in downloads. My line syncs at 19788 and I see pauses in large files the most which affects download speed but this doesnt happen with my speedtouch router. For me it happens on ADSL1, 2 and 2+ but if I swap the modem to the speedtouch its ok.

My exchange has a Broadcom chipset and the billion also a broadcom chipset but Billion are thinking either an incompatibility with the exchange or something my ISP is doing.

Using adsl info --vendor - can't find anything else that might give the info but I have only had this wee beastie up and running for just over a day - I get the following:

> adsl info --vendor
adsl: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 8000
Max: Upstream rate = 1292 Kbps, Downstream rate = 10944 Kbps
Path: 0, Upstream rate = 1279 Kbps, Downstream rate = 9655 Kbps

ChipSet Vendor Id: IFTN:0x8279
ChipSet VersionNumber: 0x8279
ChipSet SerialNumber: 2301230123012301230123012301230

From what I came make out IFTN is Infineon/Huawei manufacturer/chipset. I haven't had time to investigate any more today but have run of the roost tomorrow evening so can investigate further without upsetting the locals.

FWIW the previous modem had been off for a week while we were away and when I turned it back on it was having problems holding a sync for more than 4 or 5 minutes. I had the 7800N ready to install next weekend and this just brought things forward. The 7800N seems to be having no problems on ADSL2. Whether the old modem behaviour indicates that BT may have done some "maintenance" at the exchange last week I don't know.

Mike

I got a 7800n last December - brilliant and not one lost connection.
I don't download much, but last week got an update for AMD Catalyst Controller. It was 151764kB, and twice during the download, it paused for some seconds before resuming.
Not sure if it's happened before as I don't always watch.
One other thing I have noticed just since getting the router, is that every now and then, a web page delays in opening ...I get a page but with nothing in the address bar for around 6-8 seconds before it loads. It's mostly if I click on a link in a commercial email.

I don't know anything about exchange chipsets. I'm on ADSL2+.

Here's mine

> adsl info --vendor
adsl: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Max: Upstream rate = 1249 Kbps, Downstream rate = 22320 Kbps
Path: 0, Upstream rate = 1022 Kbps, Downstream rate = 19887 Kbps

ChipSet Vendor Id: BDCM:0xa188
ChipSet VersionNumber: 0xa188
ChipSet SerialNumber:

Maybe barking up the wrong tree totally but I just sort of latched onto your download pauses effecting speeds. I get that sometimes single pause or multiple rapid pauses but so far ping and tracert show no problems.

Who's your ISP?

Edit: I have played with virtually every setting on the router including QoS and firewall and none of them make a difference. I can also plug my speedtouch into the EWAN port on the 7800 and again problem goes away so sort of rules out the switch part of the router.

Edited by Banger (Tue 28-Feb-12 01:39:27)

Interesting TrishaH. These are the very pauses I am talking about. Correct me if I'm wrong but you are with Zen on BT 21CN?

I sometimes get stalls in normal browsing too, beginning to wonder if it's router modem firmware at fault as I can swap router and it doesn't happen.

Yes Tim - Zen/21CN

I followed your original thread with interest, so when I started getting those stalls in browsing and then that interrupted download, I knew for sure it was the same fault you'd described.

I had a Netgear DG834G on Pipex (as was) but started getting constant disconnections last Sept/Oct - was more or less totally ignorant of all things router and broadband based. I did think it was TalkTalk taking over, and indeed it did get worse at that time, so I moved to Zen - I still got the disconnections, but they pinpointed the router as the problem after a short time.
So, after asking here, I got the 7800n in December - and that's when the browser glitches started. I'd immediately thought of your thread, and wondered if it were the same thing. Last weeks update download convinced me.
The Netgear may not have held on to my connection, but it didn't stall as far as I know - certainly not with browsing.

I don't find it too annoying because I download little, so still happy with the Billion.
It's just great to have a steady, consistent connection.

Trisha

Thanks Trisha I will mention this to Billion Support on my ticket. Hope they can fix it.

OK Tim ....you work late too

I'm off for sleep now!

Trisha.

Yea me too. Thanks for the info. Take care.