1
Introduction to the RRT
(Reactive Repair Tool) Data
Version 1.0
January 2015
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About this document
Broadband diagnostic agents can use this document to familiarise themselves with BT Wholesales improved RRT
(Reactive Repair Tool) screens; including the new 28 day data view. This will significantly enhance the existing 14
day RRT view from January 2015 onwards.
Confidentiality and Legal Statement
The content of this document is confidential information for Customer use only and should not be disclosed
without British Telecommunications plc (BT's) permission. Please treat it accordingly and do not forward,
republish or permit unauthorised access.
Please note that BT has taken reasonable care to check that the information contained in this document is
accurate at the time of issue, however, it is subject to change.
Applicable BT standard terms and conditions apply.
© British Telecommunications plc
2015 British Telecommunications plc
Registered office: 81 Newgate Street London EC1A 7AJ
Registered in England no: 1800000
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Contents
•
What is RRT? (4)
•
How to Obtain Access to the Reactive Repair Tool (RRT) Data (5)
•
Where to Access the Reactive Repair Tool (RRT) Data & Graphs (6)
•
Knowledge Based Diagnostics (20C KBD): Viewing RRT Data (7-10)
•
New Knowledge Based Diagnostics (21C WBC copper): Viewing RRT Data (10-14)
•
Self Service Repair Tool (20C & 21C WBC Copper): RRT Historic Data (15-24)
•
RRT Data: Best Practice Guidance (25-30)
•
RRT Graph Parameters: Descriptions (31)
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What is RRT (Reactive Repair Tool)?
RRT is a valuable diagnostic tool that utilises graphs to show the DSL level performance of an End Users
customer service.
RRT has been available via the KBD tools for many years and supported diagnostic effectiveness within KBD, as
well as providing additional detail for CP users to analyse if required.
The enhancements that have been provided from January 2015 onwards will significantly improve the quality of
RRT information available and should allow a skilled analyst to better diagnose how a DSL service is performing.
Where a service is operating correctly, diagnostic effort can then be focussed elsewhere; but where the service is
not operating as expected a range of ‘self-service’ options may be possible to help resolve potential issues before
consideration needs to be given to requesting an engineering visit.
The RRT changes from January 2015 are;
 Additional access points provided to view RRT historic information for a service
 14 day maximum historic view enhanced with a 28 day option in KBD and as a standalone
 The ability to capture a graph image via the right click and ‘save picture as’ option is enabled. This will
save the graph as a ‘JPEG’ or ‘Bitmap’ image which can then be pasted into a circuit record, e-mail, etc.
28 Day view changes
 (21C) Addition of four 28 day Line Power views for “Tx Power”, “Rx Power”, “Power Status Mode” and
“Politeness Back off indicator”
 Addition of 28 Day “Loss of Link” view
 Addition of upstream and downstream 28 day views of line attenuation (NB: not available in daily view)
Daily View changes (1 hour sampling)
 Addition of Daily views of Upstream and Downstream “Mean Time Between Errors’ (MTBE)
 Addition of four Daily Line Power views for “Tx Power”, “Rx Power”, “Power Status Mode” and “Politeness
Back off indicator”
 Addition of Daily “Loss of Link” view
What are the benefits for Customers?
Communications Providers will now be able to review the line performance over 28 days and confirm how
stable the attenuation has been in both directions of transmission. This will improve identification on those
lines where attenuation is varying significantly due to a potential line issue.
Analysis of the improved data availability provided within RRT will better inform the analyst whether to place a
modify order to make remote adjustments to the customer’s service to provide the best possible performance.
Additional Dynamic Line Management (DLM) capabilities are being launched in March 2015; which will
enhance the CP users ability to ‘trade off’ service speed for improved stability.
The availability of daily MTBE views can provide an improved view of service operation in 1 hour snapshots in
the new RRT Historic Data functionality.
This information can be used to confirm the approximate time of service impacting events. In addition where
there has been no service impacting event; an analyst will be able to focus their investigation elsewhere.
The daily MTBE views will allow the presence of REIN (Repetitive Electrical Impulse Noise) to be confirmed
more effectively; reducing the need for an engineer where no REIN is evidenced. Where necessary, action
can then be taken by the Communication Provider to adjust service settings to improve the service
performance, whilst the environmental noise source remains.
REIN is Broad-spectrum Radio Frequency Interference from faulty or poorly designed third party electrical
equipment. Interference starts out in the power network and may impact nearby telecoms network cabling
(local access or End User network).
Often the interference is due to third party electrical equipment; usually the power supply or filtering
components, resulting in excessive levels of disturbance.
Remember though, to the owner of the REIN source equipment, it may still be operating as expected.
REIN sources do not have to be connected to the BT network to cause problems.
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How to Obtain Access to the Reactive Repair Tool (RRT) Data
To register on btwholesale.com, select Log In located at the top right of the screen. Then click on Set up a new
account and follow the instructions. Alternatively, go to www.btwholesale.com/register.
My Admin
To obtain access to the RRT graph detail your company must first set up a My Admin account on BT
wholesale.com. A nominated individual or multiple My Admin profiles can be set up as required.
The My Admin representative(s) can then authorise the access requests for their company.
To apply for a My Admin profile, select Applications, then Admin Portals, then My Admin, and complete the
My Admin Application form which you’ll find in the Downloads section on the right hand side of the page.
Send the completed form to btwholesale.direct@bt.com via the CP applicant’s manager or the Account Manager.
The CUG ID details are mandatory and access to the application cannot be processed without this information.
My Admin access lead time is up to 5 working days.
Accessing RRT graphs and other applications
To obtain access to the RRT data options log into BT wholesale (https://www.btwholesale.com) then:

Select the Applications tab and then select My Applications.

Select Subscribe to other Applications on the right side of the screen.
On the next screen, scroll down to the Manage Faults section

Check the Reactive Repair Tool option and click Submit/Ready at the bottom of the page.
Once access is granted applications will be visible in the users My Applications menu.*
*Please note: RRT (Reactive Repair Tool) will be visible and functional in the KBD and Self Service Repair tools.
Log In
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Where to Access the Reactive Repair Tool (RRT) Data & Graphs
The RRT data can be accessed via the following applications:
Knowledge Based Diagnostics (20C KBD): a separate RRT 28 Days Data button is available as well as the
default 14 day view in the Local Access Network field.
New Knowledge Based Diagnostics (21C WBC copper): a separate RRT 28 Days Data button is available as
well as the default 14 day view in the Local Access Network field. Additionally, there is an RRT Historic Data
button which provides a standalone and more detailed 14 and 28 day view of the RRT data and graphs.
Self Service Repair tool (20C and 21C RRT standalone data): There is a RRT Historic Data option in the drop
down menu; which provides a standalone and more detailed 14 and 28 day view of the RRT data and graphs.
Please note: There is a >24 hour latency on RRT data for 20CN and WBC copper circuits.
Once you've selected the required application you'll be asked to enter a PIN number provided by BT Wholesale.
Enter this PIN and click Ready.
If you already have access to Fault Diagnostics, this will be your existing PIN. The same PIN is used to access all
test applications on the My Applications menu.
If you've forgotten your PIN, click the Forgotten PIN link and answer the security question that you set up when
first registering on BT wholesale.
You will be sent a reminder of your PIN and when you next log in, you'll be prompted to change this.
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Knowledge Based Diagnostics (20C KBD): Viewing RRT Data
The user can view the 14 day or 28 day RRT data for a 20C asset via the Knowledge Based Diagnostics
application, or as a standalone test via the Self Service Repair application.
Using the 20C KBD option the user can view the 14 day option by selecting the View RRT Graph option within
the Local Access Network field; or the 28 day option by selecting the RRT 28 Days Data button.
The extended view of the RRT results is designed to help users complete a more informed diagnostic analysis.
The RRT graph detail can only be viewed after a KBD test has been run to completion.
It will be available for 24 hours after completion of the KBD test.
If another KBD test is run within that 24 hour period in the same asset then the new RRT graph detail will be
displayed against the new test and the original detail will be deleted.
The DSL (Digital Subscriber Line) layer data is provided to the Reactive Repair Tool (RRT) database every 24
hours by DLM/BIP. It provides DSL layer information on the Upstream and Downstream line rate during this
period, as well as SNR margins, Line Loss, Errors, Initialisations etc.
Please note: If no RRT data is available in these fields then no graph detail will be available.
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Knowledge Based Diagnostics (20C KBD): 14 Day View via Local Access
Network button
To access the 14 day RRT data click on the Local Access Network button in the KBD ‘Drill Down’ view (where
data is available) and select the View RRT Graph link at the bottom of the RRT Prognosis screen.
The Prognosis screen provides useful high level descriptions on the various DSL parameters performance;
including minimum, average and maximum values.
Local Access Network (RRT) outcomes:

PER = PERfect

NBS = Never Been in Synch

NSC = No SynCh

DCN = Dropping CoNnection

LTB = Lower Threshold Breach
There are 7 parameters displayed for 20C assets in the RRT graphs 14 and 28 day views (see below).
In this example the Downstream Actual Line Rate and Downstream MTBE (ES) parameters are selected.
The parameters can be selected and deselected as required to display any two parameters at the same time.
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Knowledge Based Diagnostics (20C KBD): ‘One Day 15 Minutes’ View
In the KBD views of RRT the user can also select the One Day 15 minutes View. Again, this displays up to two
parameters on the graph at the same time, but the timeline is divided into 15 minute blocks.
To display the graph enter the required date, from the list in the 14 day view, in the One Day 15 minutes View
field and click on the Display Graph button.
To view the graph detail in full screen mode, click on the maximise pane at the top right of the graph screen
Please note: The MTBE parameters cannot currently be viewed on the One Day 15 minutes View (see error
message below). So there are 5 RRT parameters displayed in the 20C KBD One Day 15 minutes View.
The day can be moved forward or back within the 14 day period by selecting the < or > buttons.
To return to the 14 day or 28 day view, select the ^ button.
To close the graph view from either the 14 day or 24 hour views, click on the ‘X’ button.
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Knowledge Based Diagnostics (20C KBD): 28 Day View
To access the 28 day RRT data click on the RRT 28 Days Data button (where data is available).
There are 7 parameters displayed for 20C assets in the KBD RRT graphs 28 day view.
In this example the Downstream Actual Line Rate and Downstream MTBE (ES) parameters are selected.
The parameters can be selected and deselected as required to display any two parameters at the same time.
Please note: Similar to the 14 Day graphical view the MTBE parameters are not available in the One Day 15
Minutes View; so there are only 5 parameters visible in the single day view.
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New Knowledge Based Diagnostics (21C WBC copper): Viewing RRT Data
There are 14 day and 28 day RRT data options for a 21C asset via New Knowledge Based Diagnostics.
Again, the user can view the 14 day RRT data within NewKBD by selecting the View RRT Graph option within
the Local Access Network field; or the 28 day option by selecting the RRT 28 Days Data button.
The extended view of the RRT results is designed to help users complete a more informed diagnostic analysis.
The RRT graph detail can only be viewed after a KBD test has been run to completion. It will be available for 24
hours after completion of the KBD test.
If another KBD test is run within that 24 hour period in the same asset then the new RRT graph detail will be
displayed against the new test and the original detail will be deleted.
The DSL (Digital Subscriber Line) layer data is provided to the Reactive Repair Tool (RRT) database every 24
hours by DLM/BIP. It provides DSL layer information on the Upstream and Downstream line rate during this
period, as well as SNR margins, Line Loss, Errors, Initialisations etc.
There is also a standalone RRT Lookup for the asset being viewed via the RRT HISTORIC DATA button. (Refer
to the Self Service Repair section for more detail on this functionality).
Please note: If no RRT data is available in these fields then no graph detail will be available.
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New Knowledge Based Diagnostics (21C WBC copper): 14 Day Graphs
To access the 14 day RRT data click on the Local Access Network button (where data is available) and select
the View RRT Graph link at the bottom of the RRT Prognosis screen.
The Prognosis screen provides useful high level descriptions on the various DSL parameters performance;
including minimum, average and maximum values.
Local Access Network (RRT) outcomes:

PER = PERfect

NBS = Never Been in Synch

NSC = No SynCh

DCN = Dropping CoNnection

LTB = Lower Threshold Breach
There are 11 parameters displayed for 21C WBC copper assets in the KBD RRT graph 14 day view (see below).
In this example the Downstream Actual Line Rate and Downstream MTBE (ES) parameters are selected.
The parameters can be selected and deselected as required to display any two parameters at the same time.
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New Knowledge Based Diagnostics (21C WBC copper): One Day View
In the KBD views of RRT the user can also select the One Day 15 minutes View. Again, this displays up to two
parameters on the graph at the same time, but the timeline is divided into 15 minute blocks.
To display the graph enter the required date, from the list in the 14 day view, in the One Day 15 minutes View
field and click on the Display Graph button.
To view the graph detail in full screen mode, click on the maximise pane at the top right of the graph screen
Please note: The MTBE parameters cannot currently be viewed on the One Day 15 minutes View (see error
message below). So there are 9 RRT parameters displayed in the 21C KBD One Day 15 minutes View.
The day can be moved forward or back within the 14 day period by selecting the < or > buttons.
To return to the 14 or 28 day view, select the ^ button.
To close the graph view from either the 14 day or 24 hour views, click on the ‘X’ button.
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New Knowledge Based Diagnostics (21C WBC copper): 28 Day View
To access the 28 day RRT data click on the RRT 28 Days Data button (where data is available).
There are 11 parameters displayed for 21C assets in the RRT graphs 28 day view (see below).
In this example the Downstream Actual Line Rate and Downstream MTBE (ES) parameters are selected.
The parameters can be selected and deselected as required to display any two parameters at the same time.
Please note: Similar to the 14 Day graphical view the MTBE parameters are not available in the One Day 15
Minutes View; so there are only 9 parameters visible in the single day view for 21C WBC copper assets.
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Self Service Repair Tool (20C & 21C WBC copper): RRT Historic Data
The Self Service Repair tool RRT Historic Data functionality is a standalone RRT lookup that does not require a
KBD test to be run before the RRT data can be viewed.
The user can view 14 day or 28 day RRT data for a 20C or a 21C asset via the Self Service Repair application.
The level of data in the RRT Historic Data functionality is higher than that via KBD and is equivalent to the BT
Wholesale view previously only visible to BTW agents via the Woosh system.
Unlike the KBD single day RRT view of 15 minutes bins, currently the RRT Historic Data view displays data in
one hourly bins for all graphical options.
The user can also run a standalone RRT Lookup from the New Knowledge Based Diagnostics test screen via
the RRT HISTORIC DATA button for the selected 21C WBC copper asset.
To run the RRT Historic Data option log into the Self Service Repair application in the users My Applications
menu; select Perform Actions, select RRT Historic Data from the drop down menu, enter the 20C or 21C
service ID and click on the READY button. An Acknowledgement screen will then be displayed.
The DSL (Digital Subscriber Line) layer data is provided to the Reactive Repair Tool (RRT) database every 24
hours by DLM/BIP. It provides DSL layer information on the Upstream and Downstream line rate during this
period, as well as SNR margins, Line Loss, Errors, Initialisations etc.
Please note: If no RRT data is available in these fields then no graph detail will be available.
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Self Service Repair Tool (20C & 21C WBC copper): Actions & Results screen
To view the RRT data select the Work in Progress link, then select Actions:
At the Results screen click on the Action ID reference for the required RRT Historic Data result:
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Self Service Repair Tool (20C & 21C WBC copper): LAUNCH RRT screen
After selecting the required Action ID result the RRT Historic Data screen is displayed.
To view the 14 or 28 day RRT data select the LAUNCH RRT button.
Please note: To keep the result for a period of up to 48 hours select the HOLD option.
There is also a BACK button to return to the results screen and a RETEST button to run the required test again.
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Self Service Repair Tool: Default 14 Day Prognosis Screen
After selecting the LAUNCH RRT option the default 14 day Prognosis screen is displayed.
There are several options for viewing RRT data from this screen:

The default 14 day Prognosis screen provides a simplistic Prognosis statement, a description of how
specific parameters are performing, min/avg/max values for each parameter; etc.

To view the 28 day Prognosis screen select the Further History link;

To display a 14 day graph select the View Graph link next to the relevant parameter.
Similar to the KBD graphical view this will open a graph where up to two parameters can be displayed at
the same time. The key difference here is all One Day views are in 1 hourly bins and not 15 minute bins;

The Diagnose further with RRT.. button provides a grid view displaying a list of days, broken down into
colour coded hourly blocks. A key to the colour codes is displayed on this screen also, as well as
additional graph & detail options;

To display the BRAT graph select the BRAT (Brandenburg Rapid Analysis Tool)-in Trial link;
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Self Service Repair Tool: Further History (28 Day View) Prognosis screen
To access the 28 day Prognosis screen click on the Further History link.
The Prognosis statement now indicates the 28 day period and the ‘to’ and ‘from’ dates covered.
Clicking on any of the View Graph links will display the 28 day view for the selected parameter and allow the user
to select other parameters. Up to a maximum of two parameters on the graph at the same time.
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Self Service Repair Tool: 28 Day View Graph screen
For 21C WBC assets there are 14 parameters displayed in the RRT Historic Data 14, 28 and single day view.
(For 20C assets there are 10 parameters displayed in the 14, 28 and single day view).
In this example the Downstream Actual Line Rate and Downstream MTBE(ES) parameters are selected.
The parameters can be selected and deselected as required to display any two parameters at the same time.
To view the one day graph enter the required date in the View 1 day 24 hour view field. The date must be
entered in the same format it appears on the graph (E.g. 01-Jan-2015) and click on the Display Graph button.
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Self Service Repair Tool: One Day View Graph screen
To view the one day graph enter the required date in the View 1 day 24 hour view field of the 14 or 28 graph
view. The date must be entered in the same format it appears on the graph (E.g. 01-Jan-2015) and then click on
the Display Graph button. The single day graph view will then be displayed (see below).
The RRT Historic Data 1 day view is displayed in hourly bins.
For the RRT Historic Data view the MTBE parameters are displayed on the single day view.
So the same amount of parameters as the 14 and 28 day views are displayed in the daily view.
The day can be moved forward or back within the 14 day period by selecting the < or > buttons.
To return to the 14 or 28 day view, select the ^ button.
To close the graph view click on the Close button.
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Self Service Repair Tool: Diagnose further with RRT..
The Diagnose further with RRT.. button provides a list of days broken down into colour coded hourly blocks.
A key to the colour codes is displayed on this screen also, plus additional graph & detail options.
To access this screen click on the Diagnose further with RRT.. in the 14 or 28 day Prognosis screens.
There are several options on this default 7 DAY VIEW grid screen:









There is a Key denoting what the different colours indicate in the hourly blocks. Also, if the user hovers
over an hourly block a description is displayed.
The colour coded hourly blocks will also contain a > symbol if there has been a profile change and
hovering over that block will display the DLM profile that was applied.
To display a 14 DAY VIEW click on the Expand button;
Report Summary takes the user back to the previous Prognosis screen;
The << button moves the view back 7 days. The forward option >> is enabled when the << option is
selected.
The < button moves the view back by a day. Again, the forward option > is enabled when the < option is
selected.
Clicking on any hour in the Hour Of Day field displays a LAYER 3 VIEW – 3 hr view across 14 day
period screen where the user can display a 3 hour view over 14 day in a graphical and tablular format.
Clicking on any of the day links (e.g. 13-Jan) displays a LAYER 3 VIEW – 4 hr view over 3 days screen
where the user can also display a 3 day graph view and access 3 days view of hourly detail in a table.
The Feedback link is not functional. Please do not use this option.
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Self Service Repair Tool: LAYER 3 VIEW – 3 hr view across 14 day period
There are several options to view RRT data in various formats from the previous 7 or 14 Day View screens.
One example is the LAYER 3 VIEW – 3 hr view across 14 day period where the user can display a 3 hour view
over a 14 day period in a graphical or tabular format.
This is the graph format with the Downstream Actual Line Rate and the Downstream MTBE(ES) selected.




The << and >> move the view forward or back 3 days and the < or > move the view by one day;
The ^ button returns to the previous screen (7 or 14 day view);
The Display Graph button displays the graph below when one or two parameters have been selected;
The Detail button displays an hourly view over 3 days of RRT measures, in a tabular format.
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Self Service Repair Tool: LAYER 3 VIEW – 3 hr view across 14 day period
This is the LAYER 3 VIEW – 3 hr view across 14 day period tabular option for the same view as the graph in
the previous slide. The Detail view displays an hourly view over 3 days of RRT measures in a tabular format.
The tabular format is in an Hourly Data format over 3 days where the user can select, or deselect parameters not
required by unchecking the relevant box(es).
There is also a more simplified Daily Data view at the bottom of the same screen and again the user can select,
or deselect parameters not required by unchecking the relevant box(es).
There are also options such as transferring this data to a csv. type file via the Download option.
The Back button returns to the previous screen.
More Details displays the hourly screen, but in 15 minute blocks. So there is four times as much detail.
The Feedback link is not functional. Please do not use this option.
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RRT Data: Best Practice Guidance
Review all data graphs, initially looking at the full 28 day view:
The upstream and downstream line attenuation provides a view of the stability of the line. A variation of 3dB or
greater (see example graph below left) indicates that changes affecting the copper line may have occurred.
It also provides visibility of the day the changes may have occurred. For example known engineering changes; via
an engineering visit, or carried out remotely.
Due to the measurement method used, variations in the region of of 1dB should be considered as normal.
(See example graph below right).
Consider if the DLM (Dynamic Line Management) is reacting as expected for the chosen stability setting:
1. Checking the error performance against initialisations.
Error/Retrain rate required for DLM to categorise a line as “poor” and look to take action:
•
•
•
More than 1 error every 5 seconds or 10 retrains per day for Standard
More than 1 error every 5 minutes or 5 retrains per day for Stable
More than 1 error every hour or 2.5 retrains per day for Super Stable
For example if a service is set to Standard and only has an average of 1 error every 5 minutes, then DLM should
take no action. Also if a service is set to standard and is running error free for long periods then DLM should
increase the speed (where possible), reducing the signal to noise margin until the service starts to error. In this
way the optimum service level should be achieved.
Please note: The recommended stability setting for a customer that has a requirement for stability over speed
(meaning less errors) and is happy with a service running slightly slower than its maximum speed is Stable.
Checking for mirroring of Noise Margin and Line Speed:
Under normal service operation when a significant change is made by DLM, the Line Speed and Noise Margin
(for the same direction of transmission) should move in opposite directions. Where the line speed is increased
when the DLM re-initialises the service, the associated Noise Margin should reduce and vice versa.
Please note: Co-incidental changes in environmental noise levels can mask this effect.
26
The example (below left) shows a normal effect; whereas the example (below right) shows where a powered
device was added to the line without appropriate line filters and effectively amplified the signal (distorting it and
causing the service to fail):
Error Performance: Mean Time Between Errors (MTBE)
To understand the error performance on a service, check the MTBE. Remember that LOW numbers are ‘bad’
(less time between errors). If a line is erroring severely this may cause throughput to drop as the data has to be
re-sent (for TCP/IP applications). Errors indicate degraded service; however errors alone do not mean a repair is
required as broadband does not offer an error free service. In fact the Standard stability setting is designed to
increase the line speed until the service errors.
As there are 3600 seconds in 1 hour, or 900 seconds in 15 minutes; an error free result will be 3600 in a 1 hour
view or 900 in the 15 minute view. It should also be noted that a single line error in a sampling period will cause a
significant reaction in the graphed result.
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Impulse Noise
In the graph below it can be seen that an impulse noise source (for example a freezer compressor) is causing a
few errors to be seen on the service. However the first spike is 1 error ((3600/1800)-1), the second is 9 errors and
the third is 1 error. So although the graph appears to show a significant service event, in reality the service had
just 11* errors in a day, which will not affect the customer’s service.
A key consideration when looking at low error events is if the stability option for the service is set to Super-stable
then noise event’s, which create greater than 24 errors in any one day, will cause DLM to slow down the service
speed and increase the noise margin. This can ultimately drive the service speed down to around 288kbit/s. To
resolve this changing the stability option for the service to Stable using a modify order and the DLM will no longer
react to small numbers of errors and the customer’s line speed will generally be restored.
It is almost impossible to locate impulse sources and as can be seen from the number of errors, they have no
effect on customer service, providing the correct stability option is used.
Nothing interesting on the downstream? – remember to check the upstream as well!
Identifying REIN (Repetitive Electrical Impulse Noise) using RRT Daily MTBE and Noise Margin plots
REIN is Broad-spectrum Radio Frequency Interference from faulty or poorly designed third party electrical
equipment.
Interference starts out in the power network and may impact nearby telecoms network cabling and/or equipment;
affecting the local access network and/or End User network.
This interference is usually as a result of a fault in the equipment, usually the power supply or filtering
components resulting in excessive levels of disturbance.
Remember though, to the owner of the REIN source equipment, it may still be operating as expected.
REIN sources do not have to be connected to the BT network to cause problems.
28
The closer the blue line gets to the bottom of the graph (shows daily MTBE) the greater the number of errors. It is
therefore possible to see that this service has occasional errors at the weekend (above dotted highlight), but
during the week there are prolonged periods with higher levels of errors as shown by the MTBE being less, which
will be due to increases in REIN noise during the week.
Friday
Saturday
Sunday
Tuesday
Wednesday
Thursday
Saturday
Sunday
Monday
Wednesday
Thursday
Monday
Friday
Tuesday
Friday
On this Saturday (graph left) the maximum level
of errors was 3 at 17:00. There were 2 errors on
5 hourly samples, 1 error in 4 hourly samples,
totalling 14 errors in 24h.
In this example it can be seen that the
Downstream noise Margin has been set to
15dB** (normally 6dB). This has been done to
compensate for the REIN noise on this service.
Making this change has reduced the maximum
number of errors in any hourly period to 144.
Therefore service is now working well with REIN
present, albeit at a slightly slower line rate.
New DLM functionality allowing a CP to amend the target noise margin will be available mid-2015
29
There are a few points to note when reviewing daily graphs:
1. Ensure the noise margin is stable as changes in the target noise margin field driven by DLM (initialisation
with corresponding line speed change) will affect the level of errors.
2. Ensure the maximum shown on the graph is consistently the same (1 hour error free is 3600, 15 minute
error free is 900) as the graph scale can change when no sampling period is error free.
Will REIN always look like this?
A. The error profile for every service will be different. Every REIN source will differ in some way and its effect
on the service will be different. What to look for:



Does the service run error free at times? (A service impacted by REIN will typically have periods
of error free running within a 28 day period).
Is there some pattern to the impact of the noise? (In some cases you may see evidence
indicating the source being turned on and off).
Does the pattern roughly align with the working hours of a business customer or when the
customer would typically be at home?
Where interference from REIN is identified there are a number of actions that can be taken:



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Identify and set most appropriate stability option.
Ensure interleaving is active.
Increase the Noise Margin (Can be increased from 6dB to 15dB in 3dB steps)
Where the noise is badly de-stabilising the service, set the service to a fixed rate.
This effectively locks the service at that level and prevents DLM from taking action
Record the noise plots and where there appears to be a correlation to customer activity discuss
the timings with the customer to see if they can identify the likely noise source.
The customer can provide additional power filtering; ranging from a simple filter in an extension
lead, to a small UPS (Uninterruptible Power Supply) system.
Q: Can REIN interference be removed?
A: REIN is Broad-spectrum Radio Frequency Interference from faulty or poorly designed third party electrical
equipment. Therefore diagnosing and repairing faulty third party electrical equipment to eliminate REIN is typically
a customer responsibility and not included within a standard broadband service.
In instances where multiple customers in the same location are suffering the same REIN symptoms the case(s)
may meet the criteria to merit an Openreach investigation.
30
Diagnostic Flowchart
This flow is intended as guidance on handling potential issues highlighted by the RRT Data:
BTW Broad Band (ADSL) Diagnostic Flow
Customer Options
BTW Documents
Diagnostic Process Steps
Process Steps
Initial Analysis
Analyst Decision Making
Replace router proven as faulty or obsolete/
incompatible for service
Line Fault Task out to
Openreach
Clear
Fault
Raise DSL SFI where further on site
investigation required.
In Sync, PPP issue,
session kill, portflex etc
Carry out
KBD Test
No Clear
Fault
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Carry out DSL service
review, including 8 points
below and analysis of
RRT information
8 points;
What is Router Type?
Is IOS version correct?
Is Firmware Version correct?
What is Current Speed?
Is MSAN Profile set to ADSL(v1) or ADSL2+
Is Banding Status Fixed or Variable?
Is Interleaving active or turned off?
Which Stability Option is set?
(Stable, Super-stable, Standard, 1,2,3)
How to carry out a
KBD Test
Diagnostic Outcomes
DSL Functioning Correctly, Investigate PPP
Layer etc
Diagnostic Review
Analysis of all information and
RRT Data to determine
appropriate next steps to be
carried out by analyst
Change Stability settings between Standard,
Stable, Super-stable and Custom, Apply
interleaving
Change MSAN to
ADSLv1 or ADSL 2+.
Order a Fixed rate DSL
Service
Carrying out a Port
reset, Port Flex &
Session Kill on the
MSAN
Customer Power
Investigation
Customer to arrange for
investigation of Mains
Power Supply to ensure
the supply is “Clean” and
free from noise
Change Firmware/
IOS
BTW CCSNR
reset best
practice PDF
REIN
BTW Port
reset, Port
Flex &
Session Kill
Placing order on BTW portal - change DLM
stability option, DSL product or MSAN
version & BTW Fixed rate product
Customer to arrange for investigation of Mains powered
devices to confirm if any devices are causing noise
interference within Mains Power supply.
Please Note; In most cases presence of REIN can be
confirmed through RRT graphs by an experienced analyst and
details passed to the customer.
In instances where multiple co-located Customers are
suffering the same REIN interference pattern, this may meet
the criteria leading to an Openreach investigation.
31
RRT Graph Parameters: Descriptions
Downstream Actual Line Rate
Upstream Actual Line Rate
Downstream Line Attenuation
Upstream Line Attenuation
Downstream MTBE (ES)
Upstream MTBE (ES)
Downstream Noise Margin
Upstream Noise Margin
Loss of Link
Politeness Power Back off
indicator
Power Status Mode
Indicates the actual Downstream DSL line rate. Units = Kbps (Kilo Bits per second)
Indicates the actual Upstream DSL line rate. Units = Kbps (Kilo Bits per second)
Indicates how much the Downstream DSL signal has degraded between the
MSAN/DSLAM and the End Customer CPE. A lower attenuation level is better for a
good signal. Units = dB (Decibels).
Indicates how much the Upstream DSL signal has degraded between the
MSAN/DSLAM and the End Customer CPE. A lower attenuation level is better for a
good signal. Units = dB (Decibels).
Indicates the level of Errors detected in the Downstream transmission, as a measure
of the statistical ‘Mean’ time between each error. A Low measure, typically <500 =
Bad, High = Good. ( MTBE = Mean Time Between Errors ). Units = Seconds.
Indicates the level of Errors detected in the Upstream transmission, as a measure of
the statistical ‘Mean’ time between each error. A Low measure, typically <500 =
Bad, High = Good. ( MTBE= Mean Time Between Errors ). Units = Seconds.
Indicates the Downstream Noise or SNR(Signal to Noise Ratio) measure at which
the DSL signal exceeds the minimum acceptable level to support a certain speed. A
lower Noise(SNR) Margin is better, but too Low can affect speed and throughput.
Units = dB (Decibels).
Indicates the Upstream Noise or SNR(Signal to Noise Ratio) measure at which the
DSL signal exceeds the minimum acceptable level to support a certain speed. A
lower Noise(SNR) Margin is better, but too Low can affect speed and throughput.
Units = dB (Decibels).
Indicates where DSL Sync has been lost between the MSAN/DLSAM and End
Customer CPE. Units = per event.
Indicates that the overall DSL band power has been reduced. This is normally only
applied to help shaping of the Power Spectral Density (PSD) in Dual Feed situations
where high levels of crosstalk disruption to other broadband services could be a
problem. Units = per event.
Note; BT Wholesale does not operate any ‘Dual Feed’ ADSL services in the UK. [1.]
Indicates the current Power State in use;
L0 State Full power management state achieved after the initialization procedure
has completed successfully (the ADSL link is fully functional)
L2 State Low power management state. The ADSL link is active but a low power
signal conveying background data is sent from the DSLAM/MSAN (ATU-C) to the
End Customer CPE (ATU-R). Units = per event.
Note; BT Wholesale has not specified the use of the L3 State (Out of Sync) for
Low Power mode use.
Initializations
Received Power
Transmitted Power
Section 9.5 in ITU-T Recommendation G.992.3 (01/2005) [2.]
Broadband Forum TR-202 ADSL2/ADSL2plus Low-Power Mode Guidelines [3.].
Indicates the number of CPE Initializations observed. Units = per event.
Indicates level of signal received from the End Customer CPE by the
DSLAM/MSAN. Units = dBm (Decibel-milliwatts).
Indicates level of signal received from the DSLAM/MSAN by the End Customer
CPE. Units = dBm (Decibel-milliwatts).
References:
1.
Discussion paper on the use of Dual Feed Infrastructure in New Zealand - http://www.tcf.org.nz/library/220fd76b0b7d-4c74-8d6d-7e9b9e05c277.cmr
1.
[2.] ITU-T Recommendation G.992.3 (01/2005) - http://www.itu.int/ITU-T/recommendations/rec.aspx?rec=7490
2. [3.] Broadband Forum TR-202 ADSL2/ADSL2plus Low-Power Mode Guidelines - http://www.broadbandforum.org/technical/download/TR-202.pdf