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Author Topic: About my possible bridge tap issue  (Read 19089 times)

Weaver

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Re: About my possible bridge tap issue
« Reply #30 on: December 03, 2015, 11:36:52 PM »

> can see why BS calls it a rats' nest

Having seen a real rats' nest in my small shed some years ago, complete with rats, I appreciate how much it is a wonderful descriptive expression. How the buggers do seem to like metal cables, steel as well as copper! Why on earth is that?
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burakkucat

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Re: About my possible bridge tap issue
« Reply #31 on: December 04, 2015, 12:25:05 AM »

And is it true that he doesn't have an access key to the cabinet.

Yes, it is true. Openreach engineers (or technicians, to use the correct description) are only responsible for the "last mile" . . . the (essentially) analogue access network via which we end users make our connection. The limits of the Openreach domain is the NTE5/A in the EUs' premises and the MDF in the serving telephone exchange. Everything deeper into the network is the domain of Operate and that is a world of (essentially) digital circuits (junction circuits, main core circuits, etc) be they over a metallic pathway or optical fibres. The "fibre" cabinets that we see out in the streets are part of Operate's domain and it is the Operate engineers (or technicians, to use the correct description) who maintain them.

If you were to look closely at the locks on a "fibre" cabinet, you will see three different types of lock on every cabinet. The standard GPO/POTel/BT/Openreach "triangle" lock, a "star" lock and a security lock. Operate engineers will have all three types of key. If an Operate engineer was to release the security lock, then an Openreach engineer could then access, with his "triangle" key, that part of the "fibre" cabinet into which the fibre-optic cable from the head-end exchange enters, the tie-cables are terminated and the low pass filters reside. The other section of the "fibre" cabinet, for which a "star" key is required to gain access, contains the DSLAM, power supply, backup batteries, etc.
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gazaai

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Re: About my possible bridge tap issue
« Reply #32 on: December 04, 2015, 12:42:09 AM »

Is it possible that Operate keep the cabinets security unlocked, as I seen Openreach at the cabinet about once every two weeks?

Oh I can see this being a waste of money then getting an engineer out, if he is just going to do a test within the home and detect nothing. I cant even get him to check the cabinet that's disappointing  :-\
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Plusnet: 80 / 20
MDWS Username: GaZaai

Modem: Billion 8800NL (Bridge Mode)
Router + AP: NETGEAR R7800 (OpenWRT/LEDE)
APs: 2x Linksys Linksys EA6700

burakkucat

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Re: About my possible bridge tap issue
« Reply #33 on: December 04, 2015, 01:07:12 AM »

Is it possible that Operate keep the cabinets security unlocked, as I seen Openreach at the cabinet about once every two weeks?

Sorry, I am unable to answer that question.  :no:

I will, however, ask if you are sure that it was the "fibre" cabinet, and not the PCP, at which you saw an Openreach technician?  :-\
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gazaai

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Re: About my possible bridge tap issue
« Reply #34 on: December 04, 2015, 01:30:00 AM »

Oh you may be right, I haven't really cared to look into much detail but I see them parked next to the two cabinets. But I think it may well be the older ADSL cabinet then.

I know you probably can't answer this question but another opinion is good. So if an openreach technician came out with his HST device and found a bridge tap fault. He would then have to contact someone else who has access to the cabinet to deal with it?

Then it would seem openreach wouldn't really care as my speed is well within the acceptable range. I guess it may still be worth getting it checked and see where it leads. :)
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Plusnet: 80 / 20
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Modem: Billion 8800NL (Bridge Mode)
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Black Sheep

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Re: About my possible bridge tap issue
« Reply #35 on: December 04, 2015, 07:44:44 AM »

Firstly, B*Cat/Weaver ..... cheers lads.  :-[

Now then, back to gazaai ..... if you go back through Kitz forum over many threads, you will see how you are pretty much taking a gamble with an engineering visit !!.

Openreach's mandate is for the Broadband Engineer to perform 3 tests ....... a Pair Quality Test (PQT ..... does as it says on the tin, tests the quality of the pair of wires from your premises back to the Exchange), a VDSL Close-out test (This is a 5-minute test that logs onto the ISP server and basically transmits and receives data whilst looking for FEC/CRC), and finally an Eclipse Test (This is basically to test the low-frequency phone part of the circuit. However, the majority of Broadband faults will see the Eclipse test incorporate a secondary test called CIDT. This 'pings' the router at different frequencies and then gives a test result. The CIDT is great for a HR-type fault, but not 'Bridged Taps').

Alas, all 3 tests mentioned above are unlikely to show a 'Bridged tap'. As I've mentioned earlier, our WHOOSH GEA remote test-bed is very, very good at determining if there is a 'Tap' on a circuit. This same test will have been carried out when you raise a fault, and will be on the engineers notes to say whether one has been detected.

As I've also said many times previously, the tests we perform will identify 95% of fault conditions no problem, it's the other 5% that cause the most consternation.

Add to the mix the fact that you wont know what engineer you're going to get, experience really does count in bundles when dealing with broadband faults. Bearing in mind we are constantly under relentless pressure to 'move on', if the 3 tests outlined above all pass, and you are within the estimated speed bandwidths ........ then a large percentage of engineers would probably close the job off as 'No fault found', and you will be charged.

The only hope you've got is either the tests do show a fault, or you get an engineer who knows what a 'Bridged Tap' is and is willing to look at the Cabinet even if all tests do pass.

 :)
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gazaai

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Re: About my possible bridge tap issue
« Reply #36 on: December 04, 2015, 02:27:49 PM »

On the phone with BT they have done tests on my line but have said it is performing fine. How do I know they are doing a "WHOOSH GEA" test and not just checking if I am connected?

Thanks
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Black Sheep

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Re: About my possible bridge tap issue
« Reply #37 on: December 04, 2015, 02:50:00 PM »

On the phone with BT they have done tests on my line but have said it is performing fine. How do I know they are doing a "WHOOSH GEA" test and not just checking if I am connected?

Thanks

I can't answer that, as I don't have anything to do with BT Retail.
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burakkucat

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Re: About my possible bridge tap issue
« Reply #38 on: December 04, 2015, 03:44:48 PM »

So if an openreach technician came out with his HST device and found a bridge tap fault. He would then have to contact someone else who has access to the cabinet to deal with it?

If the former event came to pass then, yes, I would agree with your latter presumption.

On the phone with BT they have done tests on my line but have said it is performing fine. How do I know they are doing a "WHOOSH GEA" test . . .

There is no way of knowing. If you asked the question it is highly likely that the front desk person, with whom you would be communicating, would not have a clue. Everything is "scripted", with just "yes/no tick boxes".  :-X
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WWWombat

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Re: About my possible bridge tap issue
« Reply #39 on: December 04, 2015, 05:48:57 PM »

b*cat looks towards WWWombat and asks that he please review the above caterwauling.  ;)

I'm not sure you should be converting from 68m to 680m.

But I could be entirely wrong, so I'll read the rest of the thread, then go back and read the PDF, and then research a little more...
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WWWombat

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Re: About my possible bridge tap issue
« Reply #40 on: December 04, 2015, 06:20:52 PM »

I'll bow out now as I seem to be muddying the waters.  ;) :) :)

I think the waters were muddy to start with.

However, you bring a wealth of practical knowledge, learnt/earned at great expense on real, live equipment. That's worth so much more than theory alone.
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burakkucat

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Re: About my possible bridge tap issue
« Reply #41 on: December 04, 2015, 06:28:42 PM »

. . . I'll read the rest of the thread, then go back and read the PDF, and then research a little more...

Thank you. That would be appreciated.  :)
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Black Sheep

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Re: About my possible bridge tap issue
« Reply #42 on: December 04, 2015, 09:03:02 PM »

I'll bow out now as I seem to be muddying the waters.  ;) :) :)

I think the waters were muddy to start with.

However, you bring a wealth of practical knowledge, learnt/earned at great expense on real, live equipment. That's worth so much more than theory alone.

Very kind of you to say so W3. Asbokid said exactly the same a few years ago, and he is was the mutts nuts when it came down to technology in any form. his comments were along the lines of "I've probably read every technical paper there is to read, but never put it into practice in real-life".  

Now, (as certain folk already know), I really am in awe of you guys who 'see' things that would take me a life-time to achieve. What I have learned from the guys (and gals ...... kitz  ;) ;D ), has earned me a modicum of respect at my place of work. It had to be self-taught as out home-grown courses are p1ss-poor.

So, all-in-all ....... I think we make a helluva good team on here with my role as I see it, to a) add balance to the BT-hating debates, and b) give an insight as to how we are told to operate as engineers.

To quote Aristotle, "The whole is greater than the sum of its parts. ...... which I think is very apt for this forum. Right, lets all fill our glasses and ......... well .......  get merry !!  :drink:  ;D ;D
 
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WWWombat

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Re: About my possible bridge tap issue
« Reply #43 on: December 05, 2015, 12:10:35 AM »

. . . I'll read the rest of the thread, then go back and read the PDF, and then research a little more...

Thank you. That would be appreciated.  :)

I found a different JDSU document that calculated differently, with this formula:
"160 Frequency in MHz = Tap Length in feet using the frequency in MHz at the point of the first null, or center frequency of the dip."

I'm on a tablet right now, and can't get the URL to link to. I'll add it later.
I also think the formula is more valid for US copper plant, but it is going to give us the right order of magnitude.

The first dip was around tone 164, or frequency 0.7MHz.

160  0.7 = 228 feet, = 69 metres.

I'll go back and figure out how to explain the original document tomorrow.
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WWWombat

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Re: About my possible bridge tap issue
« Reply #44 on: December 05, 2015, 09:29:59 AM »

his comments were along the lines of "I've probably read every technical paper there is to read, but never put it into practice in real-life".  

Conversely, I've read a lot of technical spec's, usually layer 2 or layer 3 interface specs, and written software to implement them. That software is a bit like Frankenstein's Monster - I let it loose, it does what I tell it, based on what I interpret real life to be from those documents. But the monster can turn on you, because real life has a habit of not quite behaving like the documents say.

I've learnt that it pays to be able to log behaviour of the monster, and to interpret logs to be able to track where real life doesn't match my ideas. Insight into real life behaviour is invaluable.

Quote
What I have learned from the guys (and gals ...... kitz  ;) ;D ), has earned me a modicum of respect at my place of work. It had to be self-taught as out home-grown courses are p1ss-poor.

Funny. I know this place works well at disseminating knowledge, but I don't tend to think it goes as far as others' workplaces. I'm not sure why that last connection doesn't happen - perhaps there are just too few people who could. But I should have seen it - especially as I'm trying to change direction from software to networking

Quote
Right, lets all fill our glasses and ......... well .......  get merry !!  :drink:  ;D ;D
Whoops. I took that bit too literally, and forgot to post this last night!
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