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This is the support site for Andrews & Arnold Ltd, a UK Internet provider. Information on these pages is generally for our customers but may be useful to others, enjoy!

CQM Graphs: Difference between revisions

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[[File:CQM-FTTC-DIS-in-one-leg.png|none|frame|FTTC running on just a single leg/wire]]
[[File:CQM-FTTC-DIS-in-one-leg.png|none|frame|FTTC running on just a single leg/wire]]
Here we have a perfectly good FTTC, running at 80M. However, in the evening the line goes rather crazy! Here is what happened:
Here we have a perfectly good FTTC, running at 80M. However, in the evening the line goes rather crazy! Here is what happened:
*18:20 End user was doing some tidying up of wiring and accidental disconnected one of the wires that make up the pair used for the phone line
*18:20 The end user was doing some tidying up of wiring and accidental disconnected one of the wires that make up the pair used for the phone line
**The line dropped a few times and reconnected, but the sync speed dropped to from 20M up and 80M down to 600K up and 23M down!
**The line dropped a few times and reconnected, but the sync speed dropped to from 20 Mbps up and 80 Mbps down to 600 kbps up and 23 kbps down!
*The line continued working for a short while, up until:
*The line continued working for a short while, up until:
*19:20 where a backup job was started which started uploading data
*19:20 where a backup job was started which started uploading data
**As the sync speed was so low, the backup filled the link and high latency (blue) ensued.
**As the sync speed was so low, the backup filled the link and high latency (blue) ensued.
**At the point the end user noticed something was not right.
**At this point, the end user noticed something was not right.
*Looking at the times on the graph gave a clue to the end user what had happened. They had accidentally disconnected one of the wires of the phone line and surprisingly the FTTC was actually still in sync, logged in and passing traffic - just at low speeds.
*Looking at the times on the graph gave a clue to the end user what had happened. They had accidentally disconnected one of the wires of the phone line and surprisingly the FTTC was actually still in sync, logged in and passing traffic - just at low speeds.
*20:00 The wiring was repaired and the FTTC came back in to sync at the usual high rates.
*20:00 The wiring was repaired and the FTTC came back in to sync at the usual high rates.
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