upload speed

Plusnet for some reason cap the upload speed on ADSL2+ to 448Kb but will uncap this if you ask,
i seem to remember reading that a higher upload has a negative effect on your download speed. is this correct?
i dont have a great connection as it is, so dont wish to lose any of my download speed.

DSL Type:G.992.5 annex A
Maximum Bandwidth (Up/Down) [kbps/kbps]:1,092 / 5,580<<
Bandwidth (Up/Down) [kbps/kbps]:443 / 5,837

The other question, why is the Maximum Bandwidth shown often less then the Bandwidth,
thomson tg585v8 router.

thanks

You've probably picked up two or three points about upload affecting download, but in general it doesn't.

The two cases where I know it can are:

- for people on ISPs who allow Annex M for upload connections. Annex M allows up to 2.5Mbps upload compared to Annex A, (the default in the UK), which only allows around 1.3Mbps to 1.4Mbps. On medium to long lines Annex M can cause a fall in downstream connection speed.

- people doing P2P downloads with too many open streams. This can choke the upload with too high a volume of ACKnowledgements. As broadly speaking the downloading server of a stream will wait for the ACKs before sending the next load, clogging the upstream with these for a lot of streams will cause a waits/slowdowns in the download. Think of how traffic on a crowded motorway can slow to a halt even when there is no actual blockage, and imposing a 50mph can in fact get everyone through more quickly as it prevents that. (Queuing theory ). That's what happens to the upstream with too many streams. But! If you double the upstream sync rate, that's the equivalent of doubling the number of lanes on the motorway. So where this effect is concerned, increasing the upstream sync helps rather than hinders.

In reply to a post by bsanotrun:

i seem to remember reading that a higher upload has a negative effect on your download speed. is this correct?

Plusnet warn you about this when you put in a request for them to uncap your upload.
But I didn't really notice a significant difference in download when they uncapped mine.

I tried the 832K add-on for a couple of days (still on ADSLmax).

Two speedtests showing the two speeds:

http://www.thinkbroadband.com/speedtest/results/id/1...

http://www.thinkbroadband.com/speedtest/results/id/1...

Sorry about the time difference between the two. I generally delete speedtests from my profile, but kept those two for other reasons.

Sounds like a briefing has entered the call centre phrase bank but not for the totally right reasons.

Two lines at house, one ADSL (448) another ADSL2+ 850Kbps. Downstream is only ever affected if I saturate the upstream with packets and is the same effect on both.

Annex M is the only time you eat into downstream sync speed for more upstream speed.

The only reason why I would be concerned about uncapping the upstream is that it makes the line unstable (it might on mine where when the phone rings it sometimes causes a resync due to too many upstream errors and that is with a 24dB upstream noise margin) and the exchange ups the downstream noise margin or worse still caps the line or during the resync the phone ringing drops the downstream margin a bit and hence get a lower sync speed

In reply to a post by Oldjim:

The only reason why I would be concerned about uncapping the upstream is that it makes the line unstable (it might on mine where when the phone rings it sometimes causes a resync due to too many upstream errors and that is with a 24dB upstream noise margin) and the exchange ups the downstream noise margin or worse still caps the line or during the resync the phone ringing drops the downstream margin a bit and hence get a lower sync speed

That sounds more like an unusually poor or even faulty line. The phone ringing should never cause the broadband to fail, quite independent of the connection speeds.

In this case it seems to be on the margin at low speed and bad at high speed, but I suggest quite untypical, in fact rare.

In reply to a post by MrSaffron:

Sounds like a briefing has entered the call centre phrase bank but not for the totally right reasons.

Plusnet: "Please note that by uncapping the upload speed there is no guarantee that the upload speed will increase, in fact it could go down."

Does that make sense, Andrew?

Sounds like utter garbage .

(it might on mine where when the phone rings it sometimes causes a resync due to too many upstream errors and that is with a 24dB upstream noise margin)

Have Plusnet tried to get that issue corrected so it doesn't interfere with the router sync to the exchange?