The FB6000 [[L2TP]] router provides us with Continuous Quality Monitoring (CQM). This allows us to track the quality of each and every connection in great detail. The router itself produces the graphs in real time, and can also provide csv files with accurate data for each graph.▼
FB6000 [[L2TP]] router provides
us with Continuous Quality Monitoring
. This allows us to track the quality of each and every connection in great detail. The router itself produces the graphs in real time, and can also provide csv files with accurate data for each graph.
Customers and Staff can view these graphs in near real time (updated every 100 seconds), and can view historical graphs.
==How does it work?==
Our router sends an LCP echo (like a ping) every second while a line is active. Your router replies. We track how long it takes for each reply to arrive, and how many are lost. These results are collated into 100 second samples and shown as a graph like the one on this page. The graph shows us lots of information about the line, and gives a history covering the last 24 hours.
==What information is on the graph?==
Each column (pixel) represents 100 seconds of samples. The hour of day is shown at the bottom, and the day and date shown next to midnight in the graph. There is additional text superimposed on the graph such as a circuit ID. There are 8 pieces of data shown for each 100 second sample as follows:-▼
Each column (pixel) represents 100 seconds of samples. The hour of day is shown at the bottom, and the day and date shown next to midnight in the graph. There is additional text superimposed on the graph such as a circuit ID.
There are 8 pieces of data shown for each 100 second sample as follows:-
===A note on Tx/Rx download/upload===
Customers (and staff) are able to add 'Pins' to graphs. This is useful for customers to add notes that staff see, for example you can add a pin saying 'Plugged router into the test socket'. The note will be shown when you hover your mouse over the pin.
[[File:Clueless-adding-pin.png|none|frame|Adding a pin to a graph]]
Pins are added on the Usage page. Simply click on the graph where you'd like to add a pin and enter in the details.
(Not an ADSL Fault.) The example above show a line with occasional short uploads causing spikes in peak latency, and then a sustained upload starting at around 6pm and causing high latency (queue in the router). At 8pm there was more upload filling the link causing higher latency still and some loss (normal when the link is full). This is normal. Also see: [[Packet Loss]]
===Congestion within BT===
This is down to congestion within the BT core network, this could be at the Exchange, BRAS, or the VP. It would be seen on multiple lines.
BT are not alone in suffering from congestion. This graph show congestion affecting TT lines on an exchange. (BT lines on the same line were unaffected by this.)
===Only Dropping during the day===
(Probably not an ADSL Fault.) If a line is dropping during the day, and maybe just Monday to Friday, then it's probably not going to be an upstream problem. This could be caused by interference of bad
wing on site. Check things like the phone line and extensions. Put the router in master socket and to unplug all other phones. Maybe change filter.
[[File:Cqm-packetloss-contactfault.png|none|frame|This line has loss due to a Battery Contact Fault. A copper line test suggest that this should be reported to Openreach as a fault.]]
===Faulty Switch on the LAN===
(Not an ADSL Fault.) This latency and loss was caused by a fault Netgear switch on the LAN side of a Vigor router! The switch had failed to the point where it wouldn't talk gigabit but would talk 100M unreliably. Guess it was maxing router CPU perhaps. It's unknown how this affected the Vigor, but perhaps the switch was faulty enough to upset the Vigor causing it to delaying or not replying to the LCP echos. In this case unplugging the LAN side of the router would show a normal looking graph, indicating the fault is somehow caused by something on the LAN.
|Going off line is shown in purple, and this is often associated with packet loss (red). Where a line has occasional drops they are shown as purple lines. However in some case a line can deteriorate over a period of time, staying on line less and less until solid purple (off line). On the live graphs a line that is currently off line has a red square in the bottom right corner where as a line that is on-line has a green square.