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Standard User Banger
(eat-sleep-adslguide) Wed 14-Jan-15 19:20:06
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Inteleaving


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After my phone fault it seems that interleaving has kicked in. Does interleaving reduce Max sync as the most I used to get was about 19 meg, now I seem to get around the 18 meg mark?

Tim
www.vivaciti.net & freenetname
Billion 7800 on 24 Meg Enta
http://www.thinkbroadband.com/speedtest/results.html...
Standard User micksharpe
(legend) Wed 14-Jan-15 19:38:51
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Re: Inteleaving


[re: Banger] [link to this post]
 
Interleaving won't affect the physical sync speed but it will reduce the line rate owing to more overhead bits being required. Interleaving is only useful for noisy lines. Of course, a noisy line may also cause the sync speed to be lowered. Useful explanation here. I'm not sure if the "sync" speed reported is actually the effective line rate.

Sweet Thames, run softly till I end my song,
Sweet Thames, run softly, for I speak not loud or long.

Edited by micksharpe (Wed 14-Jan-15 19:40:30)

Standard User Banger
(eat-sleep-adslguide) Wed 14-Jan-15 19:51:24
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Re: Inteleaving


[re: micksharpe] [link to this post]
 
Interesting, my Interleave depth for downstream according to routerstats is 96. Hope it turns off soon or will have to get ISP to force it off.

Tim
www.vivaciti.net & freenetname
Billion 7800 on 24 Meg Enta
http://www.thinkbroadband.com/speedtest/results.html...


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Standard User tommy45
(knowledge is power) Wed 14-Jan-15 20:39:05
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Re: Inteleaving


[re: Banger] [link to this post]
 
Well i found that interleave did cause my connection to sync lower both on ADSL and VDSL connections and of course with any BT wholesale based connection you also have the somewhat useless bras IP Profile which steals some throughput off you on top

Edited by tommy45 (Wed 14-Jan-15 20:40:14)

Standard User RobertoS
(elder) Thu 15-Jan-15 00:40:54
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Re: Inteleaving


[re: tommy45] [link to this post]
 
In reply to a post by tommy45:
Well i found that interleave did cause my connection to sync lower both on ADSL and VDSL connections.
Completely different software and behaviours on ADSLx and VDSL. On ADSLx it is the BT Wholesale one and only affects sync on ADSL Max where the full 828kbs is attainable on Fast Path. It drops it to 7616kbps. Even in that case some router/DSLAM combinations don't suffer it.

On VDSL it is the Openreach one running in the cabinets and the loss is well documented at an initial ~10Mbps, with further analysis available from the more detailed stats on the interleaving matrix size.
... and of course with any BT wholesale based connection you also have the somewhat useless bras IP Profile which steals some throughput off you on top
Not really so any more, not since it became a percentage of sync rather than slotting lines into sync bands and started adjusting immediately. This also has been well known for years. In effect on WBC ADSLx it simply (approximately) covers the loss due to ATM overheads by restricting the data put into the 53-bit packets to the remaining 48 bits. The actual percentage setting is 88.2%. On VDSL which doesn't use ATM it is ~96.79%.

My broadband basic info/help site - www.robertos.me.uk | Domains,site and mail hosting - Tsohost.
Connection - Plusnet UnLim Fibre (FTTC). Sync ~ 57.1/14.8Mbps @ 600m. - IPv4BQM IPv6BQM

"Angels can fly because they can take themselves lightly." - G K Chesterton.
Standard User ian72
(eat-sleep-adslguide) Thu 15-Jan-15 08:40:12
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Re: Inteleaving


[re: RobertoS] [link to this post]
 
On VDSL fastpath my downstream is normally around 48-50Mb but when interleaving occasionally kicks in it drops to around 40Mb. Generally sits there for about 6 weeks and then goes back to fastpath. At the same time my upstream normally increases by about 1Mb (from 15 to 16). And latency goes from 9ms to 16/17 ms.

All of these stats are taken as per Samknows monitoring.
Standard User RobertoS
(elder) Thu 15-Jan-15 12:17:58
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Re: Inteleaving


[re: ian72] [link to this post]
 
As I said smile.

My broadband basic info/help site - www.robertos.me.uk | Domains,site and mail hosting - Tsohost.
Connection - Plusnet UnLim Fibre (FTTC). Sync ~ 57.1/14.8Mbps @ 600m. - IPv4BQM IPv6BQM

"Angels can fly because they can take themselves lightly." - G K Chesterton.
Standard User ian72
(eat-sleep-adslguide) Thu 15-Jan-15 13:32:26
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Re: Inteleaving


[re: RobertoS] [link to this post]
 
In reply to a post by RobertoS:
As I said smile.


Indeed, was confirming with a real world example on my own line to back up your statements...
Standard User kwikbreaks
(eat-sleep-adslguide) Thu 15-Jan-15 14:18:15
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Re: Inteleaving


[re: tommy45] [link to this post]
 
Strangely enough I found with one router (I forget which) mine synced faster with interleave on - I assumed that the router noise margin algorithm had figured in a bit of an advantage from the error correction. In any event on that ADSL line with that router I found that running fastpath had an adverse effect on the throughput.

I am not running a hacked FTTC modem so have no stats but I'm guessing mine will still be fastpath if that is how it started out as I've seen no instability at all.
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