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[Pfrog]

Hi

I have a collection of routers and x 4 of them (2700HGV, DG834GT, SAR-600EW & Voyager 2500) show clearly that Interleaving is not enabled (they show Fast Path status).  However BT are insisting that Interleaving is on, - this is what I want as I have a 54db line and require Interleaving for stability.

My ISP has quizzed BT and the following is the response received :


"We have been in contact with BT again, they have checked and double checked.

The can see traffic on the element manager in the exchange clocking up
packets under interleaved.

There is no active date under the fast path logs on the element manager
at BT's end.

Regardless of what the routers show the actual packets of information
being sent to your hardware are being interleaved as they should be."


A few weeks ago I experienced a line card fault in the exchange which pushed my SNR up to 15db.  Once the fault was rectified this was reduced at my request to 9db and ever since I have had this issue about the correct Interleaving status.  Prior to the fault, Interleaving had been on, and showed correctly as such in the router status.

My question is - has anyone else had this issue??  I do find it hard to believe that x 4 routers could be misinterpreting the line status, unless the DSLAM interface is faulty and failing to handshake correctly with the router.  I am now having regular loss of sync which appears to tie in with a lack i]of interleaving.

Any thoughts / advice gratefully received!

[Mick]

All I can think of is that if you can get an IP profile of 7150 (corresponding to a sync speed of 8128 on DSLMax) then you definitely have Interleaving off.  Of course, if your house is some distance from the exchange or you have a noisy line you may never be able to get such a high sync speed/IP profile.  In that case, I am not sure how you can categorically say that you do or do not have interleaving if you cannot trust your router stats - other than by sending/receiving test packets and analysing them bit by bit (to check for burst errors) - but I wouldn't know how to do that.

If your router(s) show that Interleaving is on, it shows its depth (D 4 or whatever), it shows that error corrections  take place (FEC counts go up with time) then I would tend to assume that something is amiss with the support you receive from your ISP and or BT.

[kitz]

Hi and welcome.

Check your line stats to see the recorded errors.
If theres any FEC errors recorded then thats about the best way you will be able to tell if interleaving has been applied

If you have a high rate of CRC and HEC errors and 0 FEC errors then something is amiss for a supposed Interleaved line.


Like you say its highly unlikely that 4 different routers would be reporting wrongly.
Ive not actually heard of this particular problem before, but I have heard of it occurring the other way round on several occasions when BT insist that its off when it clearly isnt.

[kitz]

PS

Micks reply has just reminded me - that on one of my own routers Ive seen it report the line reported as "Interleaved" when it wasnt.
Interleaved depth of 1 = FAST mode.

But then - yet again that is the other way round from what youre seeing :/

[Pfrog]

Thanks for all the comments to date..... 

Just to confirm that I do have a long rather noisy line (52db notional attenauation) and do require Interleaving to be enabled.  BT are insistent that it is but x 4 routers show otherwise and all show a Fast Path status.

I am using the Solwise 600EW at present (with the Routertech 2.6 f/w) and the following is the status :

Modem Status
   
Connection Status         Connected
Ds Rate (Kbps)         3168
Us Rate (Kbps)         448
DS Margin         5
US Margin         18
DS Line Attenuation         52
US Line Attenuation         30
Trained Modulation         ADSL_G.dmt
LOS Errors         0
Peak Cell Rate         1056 cells per sec
CRC Rx Fast         164
CRC Tx Fast         1
CRC Rx Interleaved         0
CRC Tx Interleaved         0
Path Mode         Fast Path

There is no mention of FEC errors and Fast Path is clearly indicated.  There seems no area for doubt however there appears to be nothing else I can do except to accept the word of BT!

 

[roseway]

This really must be frustrating for you. I can't see any room for doubt. Perhaps the best option would be to try to persuade your ISP to get the connection reset so that it starts the training process from the beginning again. This should get interleaving applied almost immediately, as it's the first thing which gets applied when the line is less than perfect.

[kitz]

Hi

As Eric says this must be really frustrating for you.

Ive just checked out who your ISP is...  and Im really very surprised that they have taken the word of BTw after the information that you have supplied to them, as I would have thought their CS would be prepared to take this a bit further.
Looking at your comments it looks like they have at least done a WOOSH test to try and ascertain the status - but the "no active date " should perhaps start ringing some alarm bells.

Although I havent seen any specific examples of BTw saying that Interleaving has been switched ON when it clearly hasn't - I have seen many examples of BTw insisting that Interleaving is OFF when it clearly isnt, so I suppose theres no reason why it cant get stuck the other way around.

Raise another ticket, saying that you've saught advice at an adsl help forum and they are of the opinion that something is wrong somewhere in the system and can they either reject BTws claim or request a profile reset.

Before you do that though - would you do me a favour and post the results of a tracert to the bbc - as this too may help give proof whether or not if you have interleaving applied.

eg

Code: [Select]

C:\Program Files\Support Tools>tracert bbc.co.uk

Tracing route to bbc.co.uk [212.58.224.131]
over a maximum of 30 hops:

  1    <1 ms    <1 ms    <1 ms  192.168.0.1
  2     *        *        *     Request timed out.
  3    15 ms    13 ms    14 ms  10.1.2.1
  4    14 ms    15 ms    14 ms  83.245.126.93
  5    14 ms    14 ms    14 ms  212.58.238.129
  6    14 ms    14 ms    14 ms  rdirwww-vip.thdo.bbc.co.uk [212.58.224.131]

Trace complete.


Due to the time element involved, the above tracert clearly shows that my line is not interleaved.

[Pfrog]

Hi Kitz

Yes - as you indicate, the ISP (Idnet) is certainly one of the better and to be fair to them they did go back to BT by email after their initial phone conversations so I have no quibbles at all with the level of service received.  Very much up to their usual high standards.  They are rather bound by what BT tell them though.

The tracert is :

Tracing route to www.bbc.net.uk [212.58.251.195]
over a maximum of 30 hops:

  1     3 ms     6 ms     2 ms  home [192.168.1.254]
  2    25 ms    31 ms    27 ms  telehouse-gw2-lo1.idnet.net [212.69.63.51]
  3    28 ms    30 ms    28 ms  telehouse-gw3-g0-1-400.idnet.net [212.69.63.243]

  4    25 ms    31 ms    28 ms  rt-lonap-a.thdo.bbc.co.uk [193.203.5.90]
  5    25 ms    25 ms    34 ms  212.58.238.129
  6    26 ms    30 ms    29 ms  212.58.239.58
  7    29 ms    28 ms    28 ms  www-vip.telhc.bbc.co.uk [212.58.251.195]

Trace complete.

Out of interest I have tried yet another router from my collection (2700HG-B) which again confirms the Fast Path status:

DSL Connection Details     
Broadband Link
DSL Line (Wire Pair):    Line 1 (inner pair)
Protocol:    G.DMT Annex A
DSL Channel:    Fast
DSLAM:    Country: {0xB5} Vendor: {50 00 00 00} Specific: {0x00}
ATM PVC Info:    0/38
ATM Encapsulation:    Routed LLC

I confess that I can't make much out of the tracert result??

The suggestion to request a new training period is a good one (thanks Roseway) and something I will probably do.

[kitz]

hmmm the time for those traces is actually bordering the realms of an interleaved line.
I'm way up in the northwest, so unless youre right up in scotland or in NI, then I would expect a non interleaved line to be a bit less than that.

Is that taken from a wireless connection (re the 1st hops?) which would be adding additional time.

I was hoping to see something a bit clearer cut - ie a line <20ms would indicate FAST mode, so Im afraid the results are a bit inconclusive


>> ATM Encapsulation:    Routed LLC

Line shouldnt be routed LLC - although some of BTs dslams are flexible it should actually be
PPPoA and VC-Mux

PPPoE and LLC Based causes additional overheads... and in some cases wont work at all.

[Pfrog]

Yes - I was unclear about the tracert result...... No wireless link although I am using a Homeplug type link to the router which is straight into the master (with no other phone wiring).

Interesting about the LLC reference.  I had noted that before and double checked the 2700HG-B Advanced Config page and it does correctly show PPPoA and Routed VC-MUX so I am assuming that all is well.  I have found the 2700-HG-B (with the basic 4.25.19 SBC f/w) one of the best routers (if not the best of my collection), for holding on to the sync (better I believe than the 2700HG-V).  I have tried many routers / "tweaks" on my line including varieties of DMT Tool, and the DGTeam f/w on the DG834GT.  I see that the 2700HG-B resynced last night once down to 3104 with a current 11db margin.  This is probably as good as I can expect - certainly if I am still on Fast Path.

I found the DG834GT to be versatile on the tweaking of the SNR margin side, but it was a bit iffy holding sync over night on my noisy line.  The Solwise 600EW with the Routertech f/w is also reasonable but it does have a trait which I have noted on a couple of other routers in that if it identifies (correctly at the moment) that the margin is fixed at 9db, it will never ever show a higher figure, even if it is evident that the figure will have improved - during the day for example.  I suspect that this is a side effect of the router chipset used and the handshaking with the particular DSLAM in use.  As you may I gathered I have built up a fair collection of eBay (ie cheaply!) sourced routers.

To be realistic I should probably accept that my long noisy line - I am in the country with a fair length of overhead line - is a real limit to my ambitions but there is that "Holy Grail" aspect of always wanting to squeeze that last bit of bandwidth!

[kitz]

Thanks for the confirmation on VC-Mux - the LCC Based reference made me wonder if that may have been adding a little extra latency.

The powerline adapters look as if they are also adding a tiny wee bit too, but nothing drastic and about the same as some wireless connections so nothing to worry about there.

A shame that the trace proved inconclusive or it would have been a bit more ammunition for you.  In the past several times Ive had latency of up to 32ms on FAST mode after BT have been doing some re-routing, so we cant go off the figures that you have to be sure :/

Its highly improbable that 4 routers would be reporting the status wrong..  so Id go for the suggestion of a reset profile.  Luckily youre with an ISP that should be amenable to trying this for you.


>> but there is that "Holy Grail" aspect of always wanting to squeeze that last bit of bandwidth!

lol I'd be exactly the same - dont blame you
Good Luck and please let us know how it goes.

[Mick]

These are my results with Interleaving enabled:

Code: [Select]

# traceroute -I -n bbc.co.uk
traceroute to bbc.co.uk (212.58.224.131), 30 hops max, 40 byte packets
 1  10.10.10.1        6.455 ms   6.889 ms   7.430 ms
 2  195.166.128.72   29.422 ms  31.327 ms  33.309 ms
 3  84.92.4.90       37.287 ms  38.815 ms  41.254 ms
 4  212.159.4.20     46.793 ms  49.228 ms  50.766 ms
 5  212.58.239.25    54.724 ms  56.685 ms  60.666 ms
 6  212.58.238.149   62.674 ms  58.376 ms  62.033 ms
 7  212.58.224.131   63.288 ms  44.650 ms  45.266 ms
I live in the SouthEast.  So  I would guess that your line has Interleaving disabled (especially if you do not see any FEC counts rising overnight when you line starts resync'ing).

[Pfrog]

Hi

Thanks for all the comments / advice...... I am convinced that Interleaving is not enabled and will request a retrain and will let you know how it goes!

Pf

[Pfrog]

Just a brief update in case anyone may be interested!

Following additional escalation by Idnet, BT carried out further tests and "they did some resets on their side which has
resolved the issue".  Interleaving was then immediately enabled and was reflected in the modem staus as such.  Unfortunately whilst carrying out the "resets", BT yet again increased my SNR Margin to 15db.  I am now awaiting for this to be decreased to 9db - and just hope and pray that in doing so, they don't disable Interleaving again.

The morale of the story appears to be that perseverance pays with BT, and also never to accept their version of events when it is blatantly at odds with the known facts!

[roseway]

Thanks for letting us know. It looks as though things are moving in the right direction. I wouldn't have thought that there was any danger of interleaving being accidentally disabled again.