Unlimited broadband - what does it mean exactly?

[#1]

I've just signed up with Plusnet on the standard unlimited broadband package but I'm confused by the help pages explaining what unlimited means.
This one http://www.plus.net/support/broadband/speed_guide/broadband_speeds.shtml has a graphic showing that all traffic gets line speed all the time. Whereas this one http://www.plus.net/support/broadband/speed_guide/traffic_management.shtml says there is traffic management depending on what type of traffic it is. How can there be traffic management while at the same time all traffic is getting line speed all the time...it seems to contradictory?
In particular if I want to use only P2P will I get full line speed (17M for me) all the time if I'm not using any other type of traffic?
Also if I use a VPN, Cyberghost in this case which uses port 9081, will it be permanently speed limited?
Thanks for any help.

[#2]

There are no arbitrary rate limits.
There is still traffic management to give one type of traffic priority over another, noticeable if you are receiving more than one type of traffic and the same time, and across the plusnet network as a whole, in case plusnet don't have enough bandwidth to meet the total demand from all their customers.

[#3]

So in fact that graphic in the first link I gave is not true then? It claims all traffic gets line speed all the time. So I would expect to get full line speed using P2P if it was the only traffic being used by me but apparently this isn't the case. In which case Plusnet are misleading their customers by claiming it is unlimited.

[#4]

No. Just because there's traffic management giving it a lower priority doesn't mean it's not going to run at line speed 24 hours a day under normal circumstances.
Also, the Advertising Standards Agency allows services described as unlimited if:

Quote

The legitimate user incurs no additional charge or suspension of service as a consequence of exceeding any usage threshold associated with an FUP, traffic management policy or the like; and Provider-imposed limitations that affect the speed or usage of the service are moderate only and are clearly explained in the marketing communication.

http://www.asa.org.uk/News-resources/Hot-Topics/Broadband-advertising.aspx

[#5]

Honestly, Plusnet do not throttle any traffic, they proritise some of your traffic above some of your other traffic (only ever a good thing) and may, only in exceptional circumstances, slow down things like P2P when network capacity is ckose to maximum(I don't remember this actually happening in the last few years).
In normal circumstances, if you were only using P2P then that would get your full available bandwidth.

[#6]

Where is the traffic management applied? Is it at the customer's end in their router or at plusnet's end - or both?

[#7]

It's at the Plusnet gateways end. The main purpose is that when it comes to feed the data down the line to you, if the total traffic flow being sent to you is more than the capacity of your line, it knows which type of traffic to throttle first.

[#8]

Jelv meant 'prioritise' rather than 'throttle' (different meaning and customer expectations) at the gateway traffic with the highest priority is sent through first while lower is buffered and sent later. Every packet of data is sent at line speed to you regardless of its priority.

[#9]

Not true. Low priority packets are dropped and it's down to the protocol to request the resend.
(Can you imagine how how huge the buffers would have to be to store and forward packets for 750,000+ connected users?)

[#10]

I'm sure I read somewhere, there was some buffering going on, I don't remember anything mentioning the dropping of packets. Anyway, regardless of the minutia of how traffic prioritisation actually works, in the terms of the original OP's question there's no "throttling" going on.

[#11]

There is definitely a lot of buffering, although of course only a limited amount will be buffered before further packets are dropped. Even if you're only downloading one file, there will still be buffering going on at plusnet because data almost always initially gets sent towards you faster than your line can handle (you don't send your line speed to each web server you visit). The buffering was given as the explanation for why the plusnet current line speed reduces the sustainable tcp throughput slightly.

[#12]

Quote from: RPMozley

in the terms of the original OP's question there's no "throttling" going on.

If I've interpreted the foregoing discussion correctly I'd have to disagree.
Take a simple example. Say I'm streaming video while simultaneously downloading P2P and those are the only two network activities but each individually would take full line speed. According to the webpage about traffic management the P2P bit rate will be reduced, i.e. throttled, to accomodate the higher priority video stream. Yes, the total line rate is constant, assuming no network problems, but there is undeniable throttling of the lower priority P2P traffic occuring.
Of course the customer has a degree of control over this throttling as, in this case, if they wish to finish their P2P download at full line rate they have to stop the video streaming traffic and then (if i'm right?) the P2P will get full line speed. I believe that's correct and if so can understand why plusnet would traffic manage in this way to prioritise critical network traffic and stop the video stuttering or VOIP crackling etc. but their web pages didn't make that at all clear to me.
Am I right?

[#13]

Looks about right to me.

[#14]

The perceived effect to the customer, in the case of your example, would look like throttling as the p2p data rate would indeed drop to accommodate the streaming traffic.
Most customers regard 'throttling' as an arbitrary fixed cap on speeds, in terms of this definition that's not what's going on I'm sure you will agree. That's why I object to the use of the word "throttling" as people who have not understood the explanation (which, I might add, you have done correctly) will incorrectly assume there's a fixed cap on speeds, after all this is an open forum for all to see. 

[#15]

I'd modify your statement slightly:

Quote from: RPMozley

Most customers regard 'throttling' as an arbitrary fixed cap on speeds for some traffic types even if the line isn't being fully utilised