Broadband Related > ADSL Issues
ADSL / PPP / ATM / Hawk Tester
Gee:
Good morning all,
I had a recently interaction with a BT Openreach engineer that was dispatched due to a line dropping it's PPP session constantly. All EU checks had been performed..test socket, replacement router and cabling and so on, but errors could still be seen on the line.
I am led to believe that errors on the line can cause the PPP session to drop, while sync still stays up. I spoke with the SFI engineer who stated that he should not of been sent out as it is the PPP session that was dropping, but no sync. His tester did not show any drops and he stated there was nothing he could do.
In regards to the tester that the engineer uses, how to they test for PPP drops? Obviously their tester doesn't authenticate with each ISP's network, so do they simply look for any errors while the tester is on the line?
I was advised their testers does not perform an ATM layer so wouldn't be able to mimic the issue?
Black Sheep:
Hi
Firstly, I'd be very surprised to see an engineer using the more-or-less obsolete HAWK tester, for anything other than the TDR function. This function can 'see' a high-resistance fault better than the hand-held testers (EXFO or JDSU), that we currently use today .... especially a 'near-end' HR condition. :)
Now then, the problem that is dropping PPP session.
Our mandate as Openreach engineers, is to perform various industry agreed tests including ......
A PQT (Pair Quality Test - IE: The pair of wires that feed your house from the Telephone Exchange).
A DSL Close-out test ( This is the broadband test that logs-on to the ISP's radius and passes data back and forth for a pre-determined amount of time - industry standard is 5 mins, but can be set for longer if required).
An Eclipse/Fast Test2 test (Depends on how the task has been built, or how the tests is performed, but basically only tests the low-frequency phone side. As mooted, the test can also incorporate a further high-frequency test that will ping the router at various frequencies across the bandwidth).
A QLT (Quiet Line Test - used to listen for audible noise on the landline).
You are right in your assumptions that PPP can be lost whilst the router remains in synch ...... I would say (generically) in order of probability the fault is likely ............ 1) Router 2) HR fault 3) IP addressing settings (Static or Dynamic) 4) REIN.
However, you mention the engineer could see errors during his testing ??? This really boils down to the severity of the errors and what kind of error it is ?? CRC or FEC ??
A further trick we use to magnify a potential issue is to ring the landline, or make an outgoing call on the landline (usually 17070) to see if the errors increment dramatically ... pointing towards a probable metallic fault somewhere.
I don't suppose you could post some router stats up so that the proper clever people on here can peruse, and hopefully identify an issue ??
burakkucat:
--- Quote from: Gee on August 21, 2017, 11:52:29 AM ---I was advised their testers does not perform an ATM layer so wouldn't be able to mimic the issue?
--- End quote ---
I think that really depends upon which SIM (module) is being used with a JDSU HST-3000. They certainly have the ability to emulate a combined modem plus simple web-browser.
NewtronStar:
--- Quote from: Black Sheep on August 21, 2017, 08:51:47 PM ---
A DSL Close-out test ( This is the broadband test that logs-on to the ISP's radius and passes data back and forth for a pre-determined amount of time - industry standard is 5 mins, but can be set for longer if required).
--- End quote ---
This one is interesting when the OR engineer is doing the close-out test and you do a sneaky call from mobile to the landline/circuit this will confuse the engineers results is that true ?
Black Sheep:
I suppose it could, NS. ;) :)
Navigation
[0] Message Index
[#] Next page
Go to full version