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BT v PN IP Profile for speed

goldenfibre
Aspiring Pro
Posts: 2,582
Thanks: 43
Fixes: 2
Registered: 01-06-2010

BT v PN IP Profile for speed

Example1: If BTW set the line ip profile rate of 11.4Mb out of sync rate 13000K then PN current line speed would be 11.4Mb but overall true throughput speed would be 10.4Mb (1Mb loss)
Example2: If BTW set the line ip profile rate of 11.4Mb out of sync rate 13000K then PN current line speed would be 12.4Mb but overall true throughput speed would be 11.4Mb (no loss)
Why can't PN set the current line speed 1Mb higher than BTW ip profile would be best way to avoid 1Mb loss of speed on the line ?
What u think guys ?
1 REPLY
Bright
Grafter
Posts: 363
Registered: 02-02-2013

Re: BT v PN IP Profile for speed

The throughput measured by speed testers (or by timing the download of a file) is measuring the amount of user data that you can get through your connection. But that user data then has to be wrapped up in frames and packets to get it from source to destination across the internet and your broadband link. These add extra data, so the protocols have an "overhead". The BT and Plusnet profiles are limiting the total throughput including these protocol overheads. So the throughput of actual user data will always be lower than your profile because of the overheads added by TCP, UDP, IP, etc and higher layer protocols.
If Plusnet sets it's profile higher than the BT one, that means it would be sending more data to your line than the BT profile and your line sync rate will allow (when your line is running flat out). So BT will drop packets to reduce the throughput to the allowable rate. If Plusnet limits the throughput to the same as (or slightly less than) the BT rate then, if the traffic arriving for you is at a higher rate than the profile, Plusnet can buffer the incoming traffic, prioritise it to make sure the high priority traffic (eg VoIP, gaming, etc) gets through first and if things really get overloaded, it can make sure the packets that get dropped are from the lowest priority traffic streams.
Worth having a read of this.