The Line Health graph is a key indication of the status of a watch and shows 4 elements.
Affects the Load metric. CPU load is shown as a colour gradient, with red indicating 80% load or more.
Note: this may not be available, depending on the equipment manufacturer.
Affects the Health metric. Discards are measured as a percentage of overall packets sent. Colours on the graphics are:
|Discards||Up to and including 0.10%||Up to and including 0.50%||Up to and including 1.00%||Up to and including 2.50%||Up to and including 5.00%||Greater than 5.00%|
Affects the Health metric. Line Errors are measured as a percentage of overall packets received. Line errors are not available for Classes of Service. Colours on the graphics are the same as for Discards:
|Line Errors||Up to and including 0.10%||Up to and including 0.50%||Up to and including 1.00%||Up to and including 2.50%||Up to and including 5.00%||Greater than 5.00%|
Affects the Stability metric. This line shows how available your connection has been. Availability is worked out as a percentage of the day, week or month that the watch was monitored. Several issues will cause outages which are shown as coloured blips on this line and decrease the availability percentage.
You can click on the line health graphic or on the View Events button for a full list of issues and outages, with exact timestamps. See the View Events section below.
The entries you may see are summarised in this table with full details below:
|Number||Blip Colour||Issue||Effect in Highlight|
|1||Green||Transients or brief outages||Decrements stability|
|2||Mustard||Ongoing issue, cause unknown or monitoring an unknown interface||Decrements stability|
|3||Blue||No data, device not contactable or monitored interface does not exist||Stability previously decremented|
(only blue after contact re-established)
|4||Black||Device restarted, powered off/on||Decrements stability|
|5||Turquoise||Device configuration changed||No effect|
|6||Red||Circuit reported as down||Stability previously decremented|
(only red after contact re-established)
|7||Deep Red||Circuit taken out of service||Decrements stability|
|8||Bright Blue||Unknown outage type|
1. Green: Transient or brief outage
Shown as a green blip, these are brief outages which indicate the link being monitored went down and up very briefly between the times Highlight polled it. Highlight can tell this has happened because the device timestamps the last interface change, so if the state changed between consecutive successful polls there must have been a brief outage.
For example, if this link state timestamp had increased between the check at 00:00 and the check at 00:03, we know the line was briefly down between those times, even though it looked healthy both times we checked it.
For a green blip to be drawn, the line must be down for less than the polling period. The outage may have lasted for a few seconds, a minute or more. When the line comes back up, it will take a short time for routing to settle down, the router to start passing packets again, then for any connections using it to timeout and retry, so the effective outage will be longer. Highlight counts each transient outage as one minute of downtime, which is a sensible estimate.
2. Mustard: Ongoing connectivity problems
When Highlight loses contact with the device it is monitoring, we treat the outage as an ongoing issue shown by a mustard blip. Only once Highlight reconnects with the device can we check the last change timestamp for the monitored interface, which determines if the link went down whilst we were out of touch with it (the mustard colour changes to red 'Circuit reported as down'); or the link did not go down (the mustard colour changes to blue 'Device not contactable') - see next point 3.
A mustard blip will also be shown if Highlight is set to monitor an unknown interface.
3. Blue: No data : device not contactable
If the last change timestamp for the monitored interface hasn't changed when connection is re-established after connectivity problems, Highlight knows that the line has been up all the time and we simply lost contact because of a problem elsewhere on the network. Highlight marks these events by turning mustard blips to blue with the comment 'No data : Device not contactable.' There was no outage detected by the device, although it was not reachable from the Highlight platform.
The availability percentage is not decreased unless the folder option to treat blue as an outage is set to Yes.
A blue blip will also be shown if Highlight was previously set to monitor an unknown interface; or if the device does not support the "last change" parameter.
4. Black: Device restarted
This is where the monitored device has been powered off/on or restarted and is shown by a black blip. If the link itself was down before the device was restarted you will see red blips with the last blip being black. For more details see point 6 below (Red: Circuit reported as down).
5. Turquoise: Device configuration changed
This indicates a change in the configuration of the monitored device itself and is shown as a turquoise blip.
6. Red: Circuit reported as down
This is where we regain contact with the device after an outage and establish that the monitored link definitely went down. The mustard blips will turn red. Like other red issues, this counts as a formal outage on your watch, shown by a red blip and the comment 'Circuit reported as down.' The availability percentage for that watch will be decreased.
7. Deep Red: Circuit taken out of service
If the monitored link has been shut down deliberately on the device, the comment will be 'Circuit taken out of service.'
8. Bright Blue: Unknown outage type
If the outage type cannot be determined, the comment will be 'Unknown outage type'
You can click on the line health graphic or on the View Events button for a full list of issues and outages, with exact timestamps.
The following overall details for the time period selected are shown:
- an indicator that turquoise and black blips (Device restarted or configuration changed) are informational only and do not count towards Total outages
- Brief outages
- a count of green blips for brief outages
- Total outages
- the total duration (in days, hours or minutes) of all outages (green, red, deep red and bright blue blips included) and is used to calculate the total availability
- Total availability
- a percentage of the total time available in the time period (day, week or month); this will not include time before the device was activated and outages during maintenance do not impact this figure
See the Availability section above for a full explanation of each coloured blip.
For the selected time period (day, week or month) each availability event shows the time and date it occurred, the issue and the duration.
Note: Mustard and blue blips can be custom configured to be included in Total outages or not. This is set by the service provider at a folder level and inherited by subfolders unless overridden. The duration will be shown in grey text to indicate it is excluded from the total outages figure and does not affect total availability. Hovering over the line confirms "Not included in total outages".
|Blip Colour||Issue||Included in Total outages?|
|Green||Transients or brief outages||Yes|
|Red||Circuit reported as Down||Yes|
|Deep Red||Circuit taken out of service||Yes|
|Bright Blue||Unknown outage type||Yes|
|Mustard||Ongoing issue, cause unknown or monitoring an unknown interface||Custom|
|Blue||No data, device not contactable or monitored interface does not exist||Custom|
|Black||Device restarted, powered off/on|
Note: black blip indicates device restarted at some point since previous successful contact
|Turquoise||Device configuration changed||No|
Purple background areas on the chart show current and past maintenance periods. Watches in maintenance do not send alerts nor change the colour of heat tiles.
Events which occur during a maintenance window have the following characteristics:
- the maintenance icon which on hover shows "Watch in maintenance when event occurred"
- duration shown in grey with "Not included in total outages" shown on hover