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Located Very Close to 21CN Exchange, Downstream Speed Great, Upstream 443Kb

jjlukfr
Newbie
Posts: 6
Registered: ‎10-10-2010

Located Very Close to 21CN Exchange, Downstream Speed Great, Upstream 443Kb

I live within 200 metres of my local 21CN and ADSL2+ enabled exchange and at the moment my downstream rate is 23621Kb/s. Lucky me, thiis is faster than the up to 20Mb/s I should expect.
However, my upstream rate is 443Kb/s i.e. very close to but less than that for the standard 448Kb/s for an up to 8M offering and a fair bit less than the >1Mb/s available from Annex A ADSL2+.
I realise that I'm in a fortunate position but would like to get the very most from my connection and would like to determine whether this lower than expected upstream rate is a fault.
I have a Linksys WAG320N router.
9 REPLIES
Superuser
Superuser
Posts: 6,960
Thanks: 990
Fixes: 60
Registered: ‎30-07-2007

Re: Located Very Close to 21CN Exchange, Downstream Speed Great, Upstream 443Kb

Nope, by default PlusNet provision your connection with a 448k upstream cap since a higher upstream speed can sometimes reduce the downstream one. In your case that's not going to be a problem!. Just raise a ticket requesting your upstream to be uncapped and they will do it and your upstream should be closer to 1000k.
jjlukfr
Newbie
Posts: 6
Registered: ‎10-10-2010

Re: Located Very Close to 21CN Exchange, Downstream Speed Great, Upstream 443Kb

Having found a hidden info page for my router, here are the relevant ADSL noise stats etc.
--- DSL Information ---
DSL Driver Version:  AnnexA version - A2pB023k.d21d
DSL VPI/VCI:        0/38
DSL Status:          Showtime
DSL Mode:            ADSL2+
DSL Channel:       
DSL Upstream Rate:  443 Kbps
DSL Downstream Rate: 23621 Kbps
                      Down        up   
DSL Noise Margin:    3.9 dB      34.3 dB
DSL Attenuation:    10.5 dB      1.3 dB
DSL Transmit Power:  0.0 dBm    11.8 dBm
jjlukfr
Newbie
Posts: 6
Registered: ‎10-10-2010

Re: Located Very Close to 21CN Exchange, Downstream Speed Great, Upstream 443Kb

Thanks for the advice MisterW.
A ticket has been raised, I'll let you all know how I get on.
rongtw
Seasoned Hero
Posts: 6,973
Thanks: 1,533
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Registered: ‎01-12-2010

Re: Located Very Close to 21CN Exchange, Downstream Speed Great, Upstream 443Kb

PN ticket responce will tell you 24-48 hours for order to complete ,, but infact it will be near 10 days to uncap line  Undecided
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Community Veteran
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Registered: ‎02-02-2008

Re: Located Very Close to 21CN Exchange, Downstream Speed Great, Upstream 443Kb

Quote from: MisterW
Nope, by default PlusNet provision your connection with a 448k upstream cap since a higher upstream speed can sometimes reduce the downstream one.

I have serious doubts about that (the reduction), do you actually have a reference for it?
It is certainly true that the use of Annex M (upstream up to 2.5mbps and even theoretically 3.5mbps outside the UK)  can and DOES reduce downstream speed as the switchover point between the (lower) upstream frequencies and the (higher) downstream ones is moved. But without Annex M surely ADSL2+ has a fixed frequency allocation?
Any thoughts from PlusNet staff on the "real" reason?  Lips are sealed
Community Veteran
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Registered: ‎15-06-2007

Re: Located Very Close to 21CN Exchange, Downstream Speed Great, Upstream 443Kb

http://community.plus.net/forum/index.php/topic,80204.0.html
Quote
For upstream speed things are a little different. We have a choice of fixing the upload speed to 448kbps or leaving it uncapped (which has a maximum sync rate around 1Mbps). With DSL technologies there is always a trade off between speed and stability, setting the upstream speed to 448kbps means that the line (in one direction at least) doesn't run at the limits of what it's capable of so can offer a slightly more stable experience. We have also noticed that lines set to 448kbps can sometimes run at a slightly faster downstream rate, again we think this is down to the line not running at the limits in both directions so less errors will be seen on the line and thus the line remains more stable.
In my opinion it is the stability bit during the training period as the DLM system doesn't differentiate between upstream and downstream so problems on the upstream can and will increase the downstream noise margin and in extreme cases create banding - this is the last thing you want in the 10 day training period
Community Veteran
Posts: 6,735
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Registered: ‎02-02-2008

Re: Located Very Close to 21CN Exchange, Downstream Speed Great, Upstream 443Kb

Sounds like yet another reason to assume DLM is "broken", especially for ADSL2+. Angry
Over in the "real world" of ADSL2+ with people who've been doing it for a while (without DLM) almost everyone, even on extremely long lines, gets the full 1.3mbps or a very high proportion of it. Lips are sealed
Community Veteran
Posts: 38,460
Thanks: 1,031
Fixes: 62
Registered: ‎15-06-2007

Re: Located Very Close to 21CN Exchange, Downstream Speed Great, Upstream 443Kb

Not only DLM but IP profile
I could get over 20% higher speeds without it - sync 4896kbps - profile 4000kbps
and the aggressive DLM on ADSL2+ is why I have stayed on ADSL1 even though the higher upstream would be nice
jjlukfr
Newbie
Posts: 6
Registered: ‎10-10-2010

Re: Located Very Close to 21CN Exchange, Downstream Speed Great, Upstream 443Kb

Took a while for the change to be made, but here's what I have now.
--- DSL Information ---
DSL Driver Version:  AnnexA version - A2pB023k.d21d
DSL VPI/VCI:        0/38
DSL Status:          Showtime
DSL Mode:            ADSL2+
DSL Channel:       
DSL Upstream Rate:  1112 Kbps
DSL Downstream Rate: 22650 Kbps
                      Down        up   
DSL Noise Margin:    3.6 dB      9.6 dB
DSL Attenuation:    10.0 dB      1.3 dB
DSL Transmit Power:  0.0 dBm    11.7 dBm
I'm happy with that.