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Message 111 of 1,014

Re: Unplayable lag when netflix is running

I don't really understand the point your making Keith_Beddoe

Watching YouTube/Twitch/etc, is all using TCP, rather than UDP.

In this instance, upload is minimal - there's simply acknoledgements being sent since it's using TCP. 

Are you trying to suggest that these tiny segments of TCP traffic is causing high pings?

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1,116 Views
Message 112 of 1,014

Re: Unplayable lag when netflix is running

The issue is that the TCP ACKs are queued, and are uploaded as large blocks of data at regular intervals, along with the encrypted quality control information, which is why you do not see the delay on every ping reply.

This can be seen if you monitor the traffic using Wireshark, which is what I did when this issue was first raised.

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1,110 Views
Message 113 of 1,014

Re: Unplayable lag when netflix is running

Thanks for the quick response, but you've not answered the question.

Are you suggesting that the small uploads that are normal during any TCP path, are causing slowdowns?

If the answer to that is yes, who's fault is it?

I'll assume it's BTs fault if there's no response.

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1,108 Views
Message 114 of 1,014

Re: Unplayable lag when netflix is running

There may well be people who are more expert on TCP/IP who can explain it better, as I was brought up on X25 networking, which is a much more robust and secure protocol.

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1,163 Views
Message 115 of 1,014

Re: Unplayable lag when netflix is running


@Reaps wrote:

Thanks for the quick response, but you've not answered the question.

Are you suggesting that the small uploads that are normal during any TCP path, are causing slowdowns?

If the answer to that is yes, who's fault is it?

I'll assume it's BTs fault if there's no response.


Most likely its just network congestion causing data to be buffered. This is not a parameter that BT measure as part of their performance, unless it impacts on download speed.

 

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1,162 Views
Message 116 of 1,014

Re: Unplayable lag when netflix is running

Despite extensive testing, I cannot reproduce the issue on my ADSL connection which has a 10mbs download and 800Kbs upload speed.

This is not surprising as the ADSL equipment in the exchange has direct connectivity to the core network.

There is some multiplexing taking place in the exchange DSLAM, but as BT are "persuading" more people to move over to VDSL, the loading on the DSLAMs is reducing.

Unless BT Retail actually publish guaranteed minimum ping times, you are never going to get an answer.

You have the choice of trying to mitigate the effects within your own local network, or find an ISP which guarantees low latency, which I would suspect you would not find, as they cannot control what happens on the Internet as a whole.

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1,145 Views
Message 117 of 1,014

Re: Unplayable lag when netflix is running

I've moved to Zen - who don't guarantee low latency. They have don't have this issue.

Despite your extensive testing, you're were not necessarily using the same infrastructure hops as I, since i'm most likely in a different part of the network to you.

Since you're our closest contact to BT, you should be raising this internally as some sort of improvement plan. I don't know whether this is your job or not, but if you have access to mods, you should be repeating our story rather than suggesting workarounds, that either don't work or end up costing customers money while they buy new routers with QoS to try and workaround BTs issues.

If they're in the business of being a long term ISP, these issues need to be addressed.

For anyone I know who are thinking about signing up to BT, I usually do tell them of the issues I've had, with no short term fixes available.

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1,238 Views
Message 118 of 1,014

Re: Unplayable lag when netflix is running

"Most likely its just network congestion causing data to be buffered. This is not a parameter that BT measure as part of their performance, unless it impacts on download speed."

 

Sounds like they should. Why they wouldn't be interested in all aspects of their performance is beyond me.

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1,233 Views
Message 119 of 1,014

Re: Unplayable lag when netflix is running


@Reaps wrote:

 

Since you're our closest contact to BT, you should be raising this internally as some sort of improvement plan. I don't know whether this is your job or not, but if you have access to mods, you should be repeating our story rather than suggesting


I have nothing to do with BT any more, I retired nine years ago, after working for nearly 42 years, on just about every type of network from telephony and telegraphy (Telex) to optical fibre.

You could always ask BT yourself, what they consider to be acceptable latency. Its not something that the moderators would know offhand.

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1,227 Views
Message 120 of 1,014

Re: Unplayable lag when netflix is running

I did ask BT, they weren't interested.
They did say it wasn't meant to be like that though, which is why many engineers were sent out.
Fair enough, if you have no route to BT, perhaps the mods on here will have a read of these issues and raise some sort of internal ticket to track it (if only).
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