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[Weaver]

What's the record for the lowest ping-time-to-next-hop ever seen on a DSL line which has interleaving turned on?

Just out of interest..

[kitz]

Too many variables to consider - main ones being the depth of interleave..  and also location of the hops/routing.

Obviously the further the distance between the hops then the greater the latency.  Someone living up north is obviously going to have a higher next hop than someone down south.  If youre with a BTW ISP then which RAS you are connected to can also affect your next hop time.

Some routers may give priority to other types of traffic over ICMP ping .. and therefore those may show a higher than 'real-time' traffic amount of latency.

btw Bandwidth does not affect latency.

[Weaver]

@kitz
That's a very useful answer, Kitz, clarifies a number of things.

You mentioned interleave depth choices in your informative article at
    http://www.kitz.co.uk/adsl/interleaving.htm

As for seeing what interleave depth you are on, I assuming I am out of luck at seeing this on the particular DSL router, the faithful Netgear DG834 v3 I'm using right this minute. I captured a report of router state + stats at  http://forum.kitz.co.uk/index.php?action=printpage;topic=4024.0  some while ago and I don't see anything in that lot that looks revealing. Maybe guesswork has failed me or maybe I should dig around a bit more elsewhere.

I wonder if a depth of 64 will be applied by BT Wholesale kit on extremely difficult lines?

[Weaver]

I recall that Kitz wrote an article about finding where you are in the BTW network
    http://www.kitz.co.uk/adsl/RAS.htm

Tip for recognising a RAS identifier or name if you see one mentioned? Is there a kind of naming convention for them?

[Weaver]

Anyway, I'm assuming that 45ms for a ping-to-'nearest' hop is a decent value for an interleaved BTW line where depth is set high?

Sanity check : And where 'nearest' of course is no such thing as I'm assuming [?] it's taking you to the far end of some tunnel, taking you right through BT-land skipping over an unknown number of BTW nodes ?

[GunJack]

If it's any help, I'm on 32 depth interleaving, and get 34-37 ms to speedtest.net's sittingbourne, milton keynes and maidenhead servers, 45-ish to manchester and coventry, and higher to the others.

I'm in north wales on a tiscali LLU dslam

[Weaver]

Thanks gunjack.

So I could be on a depth of 64, thats what I was assuming. The best ping to 'first' hop (first in AAISP-land that is, so not first at all) I've ever seen on the long, long (62dB attn, 2Mbps) line I'm using right now is 45ms.

ESR4.Edinburgh5 or similar is the RAS if I remember rightly, having followed the test described in the article kitz linked to for capturing a log of the ppp session on a Netgear box.

[kitz]

>> Is there a kind of naming convention for them?

ESR4.Edinburgh5

Edinburgh RAS. LAC no 5. Edge router = Cisco ESR no 4

[HPsauce]

For info I normally get around 6or7ms to the BBC with Fastpath and 13 to 14ms (as now) interleaved (depth 160 according to DMT).
That's on Be.  8)

[kitz]

I dont look at my connection any more it only pees me off.

The days of my supposed 24Mb connection are long gone and my deterioration continues.  
Im now down to 20Mb with a target SNR of 3dB. God knows what it would be if I was at default 6db and interleaved.
 
Im like 170 yrds from the exchange, but I hold out little hope of anyone doing anything about the loss of 4Mbps of speed.

The line is stable and generally holds well.  In fact it will hold on quite well at 2db.  Its just every few weeks I'll loose more SNR, which will eventually cause a resync.   At resync I obviously loose even more speed.

I darent resync at any point, so I cant test or play with anything anymore. Ive done all I can here.. and I know many would kill for 20Mbps..  but there is something wrong with this line..  and the loss of 4Mbps is quite a lot.   This line should perform at 24Mbps easy.

[Weaver]

> Im now down to 20Mb

[ ! ]


Sobs.

[Weaver]

A thought. I suppose I should also have asked what the lowest ping time ever seen is on a very BTW short line with no interleave.

Anyone any idea of the typical time the BTW network adds in the trip through BTW-land to your favourite ISP and back?

[torqpoc]

Im now down to 20Mb with a target SNR of 3dB. God knows what it would be if I was at default 6db and interleaved.

Even at 20Mb.. major envy!

Cheers,
T