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[adslgeek]

Hey there,

I have seen some customers on Huawei 880 synching on an 7645kbps Actual synch rate, but with a high Attainable (eg 22Mbps) and this appears to be on ADSL2+ only.

Dunno if anyone else has seen this as a trend?

Cheers,

[adslgeek]

Hey also, I have seen similar with one of the Mako modems but this synchs at 7616 (But using ADSL2+), and with a higher attainable (I am not sure if Mako are sold outside NZ?).

The Dlink 502T in NZ is seeing a synch rate of 7547kbps synch, but not a factor when interleaving is removed.

And last but not least is some of the old Linksys routers (I am assuming eg WAG200) a similar reported issue of slow actual synch, but I have not confirmed the synch rate that this is having, but it is near the 6 or 7Mpbs range (and on ADSL2+)

I suspect that if interleaving is off, this is not a problem, (As this is similar to a Dlink issue) but I have not tested this just yet.

Again - not sure if this is relevant to the UK modems, but keen to hear if others are seeing this too. :-)

[kitz]

Not seen/heard anything like that.  One of the major UK LLU providers uses the 882 rather than the 880 though.

The main thing that strikes - Is the line actually configured to adsl2+?
7645 seems like either an (LLU) adsl1 sync - or alternatively it could just be throttled to that speed by the provider.

The routers may well be adsl2+ compatible, but if the exchange/MSAN/line config isnt adsl2+ then the router wont be able to actually sync at the higher speeds.

The fact that it shows a high attainable rate, is just an estimation by the router of what speeds would be available if adsl2+ was available on the line.
I had an old Voyager router which was only adsl1, yet it used to show an attainable figure that was in the realms of adsl2.

[adslgeek]

Kitz you will love this one!

It turns out in NZ we have interleaving depth of 12dB and that router firmware hadn't been configured this way, and this was what was causing this synch rate issue.

To fix, I sent through heaps of detail through to Huawei and they have re-written the firmware and that works sweet.
The other way to fix it is to remove interleaving which is fine as long as the line is OK. What interleaving depth is used in UK?

There is a large formula which you can use to calc the synch rate based on interleaving depth, but I didn't follow it that well. 

I have done a bit of research and this also impacts Mako routers (not sure if they are sold in UK) with a similar synch rate, and the Dlink 502T synchs at 7547kbps also with most of their firmware versions.

I have noticed several other synch rates that seem fairly common so I will continue to try to work out if they correlate to a particular brand. I understand that without DLM in NZ there are about 10% of the modems have synch rates close to the 7Mbps mark but with (much) higher attainable..

Cheers,
Adslgeek.

 

[hake]

It would be much appreciated if you could please provide a link for this firmware download.

[Azzaka]

...
I have done a bit of research and this also impacts Mako routers (not sure if they are sold in UK) with a similar synch rate, and the Dlink 502T synchs at 7547kbps also with most of their firmware versions.
...

This may also be that the modem cannot cope with INP as it uses Extended Ethernet Framing. Just a thought.