1.4. Registered Parameters

Graphs

Name	Description
Download Rate	a graph representing a download rate over the HTTP/HTTPS protocols. Download rate for HLS-streams is defined as the ratio of a segment size to its download time.
Input bitrate	a graph showing total bitrate of incoming UDP/RTP stream.
PID Bitrates	a graph showing payload data bitrate (audio and video streams), EIT (Event Information Table) and padding (null packet, PID 0x1fff) data.
EPSNR	a graph showing a statistical estimate of the digital video content distortion during encoding. It is expressed in dB and defined as a ratio of peak mean square video signal to mean square deviation of the output signal from the original one. EPSNR (Estimated Peak Signal to Noise Rate) value estimation is based on encoded video stream data, i.e. no original video content (not encoded) is required. EPSNR is used to estimate encoders’ performance quality. To estimate it the following values may be used: 25–30 dB — low quality, 45–50 dB — high quality.
Maximum Inter-packet Arrival Time (IAT) : Media Loss Rate (MLR)	a summary graph representing IAT and MLR parameters. This graph is available for IPTV monitoring only. This parameter allows detecting network signal losses and jitter in details. Two horizontal lines displayed on the graph indicate warning and error thresholds of the IAT parameter. Four-colored scheme is applied: green belongs to the IAT values that are lower than the stated warning threshold; yellow belongs to the values that are higher than the stated warning threshold but lower than the error threshold; orange — IAT values exceed the error threshold. No signal value is highlighted red. To set thresholds for both parameters, go to the Project Settings ➝ Task profiles ➝ Thresholds.
MDI Media Delivery Index [Delay factor (DF) : Media Loss Rate (MLR)]	a summary graph representing Delay factor (DF) and MLR parameters. This graph allows estimating signal delivery quality based on the two parameters: packet loss and indirect analysis of a signal jitter (based on DF values).
Continuity Counter Errors	a graph showing CC errors (TR 101 290 error 1.4 Continuity Counter) distribution.
PTS/DTS Discontinuity Errors	a graph showing PTS/DTS Discontinuity errors distribution.
Audio Loudness	a graph showing audio loudness measurements. Momentary and Short-Term Loudness are registered in LUFS.
Ads insertion	a graph showing ad insertion markers.
Availability Trend 24h	a graph showing the Service Availability state for the 24-hour monitoring period. One bar corresponds to 2 hours. A bar color corresponds to the color map of Availability levels set in KPI — Service Availability. A mini graph moves right to left, i.e. the rightmost bar shows the service state for the last 2 hours. Clicking the trend graph, you can see the tab 15 minutes which provides the details of availability for the following types: Total availability, QoS/QoE availability. The statistics for each type includes monitoring type, number of Error Seconds, percentage and trend of availability for the last 24 hours. When switching to the tab 24 hours, graphs with detailed information for each 15 minutes within 24 hours will open.

Thumbnails

Thumbnails — capture of video thumbnails within the specified time interval. In addition, thumbnails capture interval should be set up for the detected advertisement period marked with the SCTE-35 and for the stream freeze period. Enable the “Thumbnails capture” checkbox in the task configuration form to activate thumbnails capturing.

Parameters, Events and Errors

Name	Description
Mapping	an array specifying the number of TS packets included in one IP packet, which have been detected within the last 3 seconds according to frequency of their occurrence. Usually, one IP packet contains 7 transport packets.
TOS/DSCP Changed	Type-of-service, field in IP header.
TTL Changed	Time to Live.
Src address	IP address and port of multicast source.
Src MAC	IP and MAC addresses of multicast source.
Dst MAC	destination MAC. IPv4 multicast packets are delivered using the Ethernet MAC address range 01:00:5e:00:00:00–01:00:5e:7f:ff:ff.
Maximum Inter-packet Arrival Time (maxIAT)	a graph representing maximum inter-packet arrival time. Packet jitter can be detected by checking inter-packet arrival time. Maximum IAT is defined as a summary of average IAT and jitter. Maximum IAT value is measured every second. Calculated in milliseconds.
Min IAT	the minimum inter-packet arrival time registered per a second. Calculated in milliseconds.
Avg IAT	the average inter-packet arrival time recalculated each second. Calculated in milliseconds. The Avg IAT value is close to the expected IAT value for Constant bitrate stream with the constant mapping that equals 7.
MDI Media Delivery Index [Delay factor (DF): Media Loss Rate (MLR)]	an index indicating the quality of video streaming delivery network. The network is sensitive to jitter and data losses. It provides accurate measurement of a stream jitter which defines bitrate fluctuation from the expected values and Media Loss Rate (MLR). Bitrate fluctuation caused by jitter and MLR can be considered as depth of virtual buffer (DF) used to buffer received packets of a stream.
MLT/MLS 15	Media Loss Total 15 — the total number of media packets lost for the last 15-minute inspection period. Media Loss Seconds 15 — the period of time in seconds during which packets were missing within the last 15-minute inspection period.
MLT/MLS 24	Media Loss Total 24 — the total number of media packets lost for the last 24-hour inspection period. Media Loss Seconds 24 — the period of time in seconds during which packets were missing within the last 24-hour inspection period. These metrics provide the total statistics for the last 96 inspection periods (summary of all 15-minute intervals within 24 hours).
Several broadcasters	several broadcasters in one multicast group.
Task Has No Subtasks	It triggers depending on the protocol type when: HLS and DASH The service analysis task has only a Manifest task and doesn’t contain any subtasks. This may occur when in the manifest (playlist) no links to a media representation or to a variant stream can be found (HLSv3). At the same time, the manifest (playlist) is reachable and valid. SRT The task analyzing a SRT stream has only a Master task and doesn’t contain any subtasks. This may occur when the task is active and started in the Listener mode. At this time, a task doesn’t receive any SRT streams and waits for incoming connection.
PCR	Program Clock Reference detects synchronized signals in the selected stream. It is displayed in the “Service information” dialog window as the clock icon. The PSI (program specific information) event contains PCR information. For UDP (RTP) and SRT: when the PCR is not detected in a stream for the 3-second period, the PCR Is Not Present trigger fires. The PCR is used to calculate elementary stream bitrates. In case the PCR is not detected, the analyzer switches to the use of the system time in a 1 minute. The state disappears as soon as the PCR occurs again. Attention: if the PCR has already disappeared, but the probe has not switched to system time yet, elementary stream bitrates and most of TR 101 290 time-counting errors cannot be detected correctly.
Encrypted stream	is displayed as the lock sign in front of an elementary stream in the “Service information” dialog window. The symbol can be viewed on different dialogs and it indicates encrypted elements. PSI (program specific information) event contains encrypted stream information. Video freeze analysis, thumbnails capture and EPSNR calculation are not performed for such streams.
Invalid elementary stream	the lightning icon is shown for the related elementary stream in the “Service information” dialog window. If a probe receives ES video content with the specified PID but no video headers (SPS, PPS) are detected within 20 seconds then this stream is marked with the Invalid ES sign (invalid data or encoded stream). PSI (program specific information) event contents invalid ES information. Video freeze analysis, thumbnails capture and EPSNR calculation are not performed for such streams.
Video information	video streams headers are transferred to the server. Based on the received data a table is created in the “Video information” dialog window. The table contains the following parameters: coding format, resolution, frames per second (FPS), frame size (height-to-weight ratio), etc.
Audio information	audio streams headers are transferred to the server. Based on the received data a table is created in the “Audio information” dialog window. The table contains the following parameters: format, number of channels and sample rate.
Download rate	download rate over HTTP/HTTPS.
Multicast bitrate	the total volume of received transport stream data on the software analyzer’s input for 1 second of the probe’s system time. The counter includes container overhead but no other overhead imposed by the delivery system or a protocol. (RTP, UDP, etc.).
Current bitrate IPTV/SRT	the sum of all elementary stream bitrates and other data including null (stuffing) packets (PID 8191) contained in the MPEG TS. The stream bitrate is measured over a time period of 1 s considering PCR timestamps. Attention: if PCR is missing, the probe will not be able to correctly detect elementary stream bitrates for 1 minute, as well as most of TR 101 290 errors.
Min/Max bitrate	minimum and maximum values of Current bitrate since the counter last reset. It is displayed: in the Service information dialog window (measured when opening the window); at TableView.
Useful bitrate	the sum of all elementary stream bitrates and other data contained in the MPEG TS excluding null (stuffing) packets (PID 8191); packets with unknown PID; packets with the Transport error indicator (TEI) set. The stream bitrate is measured over a time period of 1 s considering PCR. If the analyzer fails to detect any PCR timestamps, the probe system time will be used to count the interval. Attention: if PCR is missing, the probe will not be able to correctly detect elementary stream bitrates for 1 minute, as well as most of TR 101 290 errors.
Encoded stream average bitrate	average bitrate of elementary video streams calculated during 5, 20 and 60 sec. periods. It is displayed in the “Video information” dialog window and is measured when opening the window.
Info/Stop	the following events are registered in the events journal: data occurrence at the probe input and the task stop.
BadSource	events confirming that the probe cannot receive data for further analysis are registered. The following criteria are applied for different protocols: UDP/RTP — lack of input data for more than one second; HLS — the segment download is impossible since a playlist has no changes. 3 attempts of the playlist downloading are performed with the interval equal to duration of the last segment. If after three attempts no changes appear in the downloaded playlists, BadSource is registered; for HTTP/HTTPS — zero download rate for particular time (5 sec. in average). During this time data is taken from the input buffer by the probe.
VideoFreeze	analyses video freeze. It is displayed on LiveView and as a snowflake sign in thumbnails area or in the “details” field. The analysis is performed in two steps. Size ratio of I frames to P frames is measured in the first step. If the ratio exceeds the stated threshold, both neighboring I frames are decoded and compared by edge points in the second step. To enable video freeze analysis, set a checkbox “Video Freeze Detection” in the task configuration form.
TR 101 290 errors	monitoring of ETSI TR 101 290 errors. The errors are displayed as a group of green blocks (or red blocks in case of active errors). The TR symbol is displayed on a thumbnail or in the “details” field if the errors occur in a stream. The following errors are registered: Priority 1 TS Sync_Loss; Sync Byte Error; PAT Error; СС Errors (reflected in the “Service information” dialog window): Number of errors is measured when the window opens; Number of errors over the last hour; Number of errors since the stream analysis has been being started. PMT Error; PID Error; Audio/Video PID Error. Priority 2 Transport Error; CRC Error; PCR Repetition Error; PCR Discontinuity; PCR Accuracy Error; PCR Is Not Present; PTS Repetition Error; Timestamp Discontinuity; CAT Error. Priority 3 NIT Error; SI Repetition Error; Unreferenced PID; SDT Error; EIT Error; RST Error; TDT Error; Buffer Error; Empty Buffer Error.
Parsing and displaying transport stream tables	probe registers tables SDT, BAT, NIT, PSI and detects related errors. Also the probe detects the presence of EMM/ECM.

Quality of Experience (QoE)

Name	Description
Program Specific Information Changed	PAT, PMT and SDT programs description of the analyzed stream is transferred to the server. Based on the received data a table is created in the “Service information” dialog window. All elementary streams types (“Type” field) are shown in the table.
Audio Loudness	the following criteria are measured: program loudness and peak levels of audio signals according to EBU R 128-2011: Programme Loudness Momentary Loudness Short-Term Loudness Loudness Range Maximum Permitted True Peak level audio silence in accordance with specified thresholds.
Encryption State Changed	triggers if encryption state is changed. Encryption state change of any elementary stream contained in the service is considered.
Video Information Changed	triggers if video stream header changes (format, profile, resolution, aspect ratio, frame rate, etc.).
Invalid Video Elementary Stream	occurs if video headers (SPS, PPS) are not detected in a stream for 20 seconds that does not allow decoding the stream. The parameter is used only for video elementary streams. The stream may be encrypted.
Video Freeze	occurs if Video freeze is detected during the specified period.
Video Decodability Error	occurs if the number of correctly decoded frames is less than the threshold.
Audio Information Changed	triggers if audio stream header changes (format, channels, sample rate, etc.).
Audio Track Missing	triggers if sound is missing in a program (there are no audio PIDs).
Audio Decodability Error	the state occurs if bitrate of the decoded stream is less than the threshold.
Audio Silence	occurs if audio silence is detected in a sound track. There is a sound track in a program but its Short-Term Loudness is lower than the threshold.
HDR headers	display of HDR headers in the Video information window. All basic HDR formats are supported.

Digital Program Insertion

Name	Description
SCTE-35 Tags logging	the probe registers the SCTE-35 tag (splice_insert command or/and time_signal command) carried in a transport stream to Event journal.
SCTE-35 Advertisement Insertion	triggers when the probe detects the start of an Ad insertion (based on SCTE-35 tags data). The state disappears when the probe detects the end.
SCTE-35 Ad Insertion Exceeds the Specified Period	triggers when the duration of an Ad insertion exceeds the specified period. The probe initiates counting of the period as it detects the start of an Ad insertion.
SCTE-35 Tags Parsing Error	triggers if the error was detected while Ad insertion tags parsing. The error details are returned in the message.
SCTE-35 Ad Insertions Are Missing	triggers when the probe does not detect the start of an Ad insertion (based on SCTE-35 tags data) during the specified period. The state disappears when the probe detects an Ad insertion start. The trigger is implemented on the basis of the SCTE-35 Advertisement Insertion event.
SCTE-35 Tags Are Not Present in the Playlist	triggers when the probe does not detect SCTE-35 tags in a playlist during the specified period. The trigger is implemented on the basis of the “SCTE-35 Tag in OTT Playlist” event. For subtitles, you can disable SCTE-35 tags monitoring in Thresholds settings.

OTT Parameters

Name	Description
Type	task type. The following types are possible: master — for a parent task (the Master playlist analysis) in the AllRenditions mode; media — for a task started directly for the Media playlist analysis (a Master playlist is unknown); player — for a parent task in the Player mode; video — for a task analyzing a Variant Stream; audio, subtitles, video — for analysis tasks of alternative Audio, Subtitles or Video Renditions, respectively.
Signal	time since the last signal recovery.
Resolution	Variant Stream resolution (W x H), declared in a Master Playlist.
Bandwidth	Variant Stream bitrate, declared in a Master Playlist, in bits per second.
Actual bitrate	actual average bitrate of a segment. It is calculated as: Segment size / Segment duration, in b/s.
Download speed	segment download speed. It is calculated as: Segment size / Download time, in b/s.
Segment duration	duration of a downloaded segment declared in a Media Playlist, in seconds.
TTFB	time to first byte (TTFB) measures the duration from the time of an HTTP request to the first byte of the segment (manifest, key) being received by the probe.
DNS Lookup	time taken to determine the domain name associated with an IP address.
TCP Connection	time required to establish a TCP connection.
Download time	segment download time, in seconds.
Segment size, B	exact size of the downloaded segment, in bytes.
Segment size, MB	approximate size of the downloaded segment, in Mbytes.
IDR/Indep	indicates the presence of an IDR frame and INDEPENDENT tag: Start with an IDR frame — if a segment is not encrypted and is not flushed before starting analysis, the probe monitors if the segment starts with the IDR frame (under HLS specification requirements). In case the segment starts with the IDR frame, the field value is OK; if not — the field value is Error. INDEPENDENT tag — a logical type; Yes indicates that the #EXT-X-INDEPENDENT-SEGMENTS tag is detected in Master or Media playlists.
Source IP	the actual IP address (after domain name resolving and redirecting to the last address) from where the data was received.
Effective URL	the final URL that the probe receives when it sends a request to the CDN.
Downloaded	date and time of a segment download.
Interface	interface for data receiving.
Current bitrate OTT	the sum of all elementary stream bitrates and other data including null (stuffing) packets (PID 8191) contained in the MPEG TS. The stream bitrate is measured over a time period of 1 s considering PCR timestamps. It is displayed in the “Service information” dialog window and in the TableView mode.
Min bitrate	the minimum current bitrate measurement since the last reset of a counter.
Max bitrate	the maximum current bitrate measurement since the last reset of a counter.
HTTP headers	all headers contained in the response from server when downloading a segment or playlist.

OTT Events and Errors

Name	Description
Variant Stream Switching	the event of switching to a Variant Stream with different bitrate is registered. It is applied only for the probe in the “Player” mode.
The Number of Variant Streams Changed	HLS: It triggers if the number of Variant Streams in a Master playlist is changed. The Update MasterPlaylist option should be enabled. DASH: It triggers if the number of media content Representations declared in the manifest within the analysed Period has changed. When going to the next Period, the probe will compare the number of Representations between Periods.
Minimum Variant Streams	HLS: the number of Variant Streams stated in the Master playlist is less than the minimum threshold. DASH: It triggers if the number of video Representations declared in the manifest within the analysed Period is less than the minimum threshold.
Variant Stream Attributes Changed	HLS: It triggers if any Variant Stream attribute contained in the Master playlist changes (a line that follows the EXT-X-STREAM-INF tag). DASH: It triggers if the Presentation description changes (a line containing attributes of the Representation element) declared in the manifest within the analysed Period. When going to the next Period, the probe will search for similar Representations and compare descriptions between Periods.
Duplicate Bandwidth in Variant Streams	triggers if the Master playlist or manifest has two similar Bandwidth values for different Variant Streams within the same codec. The Bandwidth parameter is the upper bound of the overall bitrate for each segment, in bps. It includes any container overhead that appears or will appear in the playlist.
Bandwidth Missed in Variant Stream	triggers if the Bandwidth field is not present in the Variant Stream description of the Master playlist or manifest. In the Player analysis mode, the probe will not switch to Variant Streams with the Bandwidth field not specified. If there is no bitrate information for all Variant Streams, the probe analyzes an arbitrary Variant Stream without switching to other Variant Streams. Additionally, such Variant Streams will not be analyzed for the following characteristics: Duplicate Bandwidth in Variant Streams; Actual Bitrate; Bad Segment Size; Bad Segment Duration.
Invalid Resolution in Variant Streams	the declared height or width of the video resolution is out of the range 16..65536 or the DASH manifest declares only one resolution attribute (@width or @height).
Duplicated URI	some Alternative renditions or Variant Streams have the same URI in a Master Playlist or in a manifest.
Sequence Divergence in Variant Streams	divergence occurs in the #EXT-X-MEDIA-SEQUENCE fields in Media playlists. All declared Variant Streams are compared.
Few Segments in Manifest	the number of segments stated in the Media playlist is less than the minimum threshold. DASH: only those MPD files can be validated in which Segment List information is specified for the SegmentList element.
Static Manifest Error	the Media playlist has not updated during subsequent downloads (the same playlist is downloaded). DASH: only those MPD files can be validated in which Segment List information is specified in the SegmentList or SegmentTimeline element.
Manifest Size Error	size of any playlist exceeds the Manifest size threshold.
Manifest Error	Depending on an OTT type, it triggers if: HLS Media playlist URI has not been parsed in the Master playlist; Segments URI has not been parsed in the Media playlist, or the segment URI has the .m3u8 extension (i.e. link to a playlist); The “\n” symbol is missing in the end of the playlists; The alternative rendition does not refer to any stream variants; Failed to parse a #EXT-X-KEY tag content. DASH Manifest does not conform to the DASH XML Schema.
Unknown Manifest	the playlist content does not comply with the standard, or the playlist is empty.
Manifest Download Failure	a playlist cannot be downloaded. The error cause is saved in the Alarm journal: as HTTP status code or as curl error detailed description. The playlist download timeout is 15 seconds.
Media Playlist Event	the Media playlist URL has been changed (HLS) or the playlist type (VOD/Event/Live) has been changed.
Custom Tag	triggers if the probe detects a custom tag. Tag detection filters can be specified in the “OTT custom tag detection” section of the Thresholds and Recording tab.
Actual Bitrate	average bitrate of a downloaded segment is higher or lower than than the specified thresholds.
Bad Segment Size	it triggers if the segment size (content-length) is equal to 0 bytes or average segment bitrate exceeds the bandwidth (stated in a Master playlist) by 10 times. Additionally, if the segment size is more than 15 MB, the download of this segment is terminated. Average segment bitrate is calculated as the file size (content-length) divided by declared segment duration.
Download Bitrate Low	low download bitrate of a segment is registered (download time exceeds warning threshold). Trigger conditions: download time / segment duration >= warning threshold (%). Warning threshold cannot exceed an error threshold.
Download Bitrate Too Low	download bitrate is too low. If download speed is lower than the stated Download speed error (download_speed_error) thresholds, a notification is automatically generated. It is expressed in % and calculated as download time / segment duration >= error threshold (%).
Segment Download Failure	segment cannot be downloaded. The error cause is saved in the Alarm journal: as HTTP status code or as curl error detailed description.The segment download timeout is equal to double the segment stated duration, but not less than 5 seconds.
Key Download Failure	a decryption key cannot be downloaded. The error cause is saved in the Alarm journal journal: as HTTP status code or as curl error detailed description. The playlist download timeout is 15 seconds.
Segment Loss	one or several Media playlists (#EXT-X-MEDIA-SEQUENCE discontinuity) along with segments are missing during analysis. Only for HLS. There are several causes of the error: segment download bitrate is too low that results in skipping download of subsequent playlists; playlists are not available for downloading (“Manifest Download Failure” triggers additionally); issues with content generation at the headend: broken numerical sequence of playlists, restarts or pauses in transcoders/serializers operation. Note, if skipped playlists do not result in segments loss, the error does not trigger.
Bad Segment Duration	declared segment duration exceeds or less than the estimated duration by 10 times. Estimated duration is calculated as the segment size (received in a header of http server response) divided by declared bitrate of variant stream (SegmentSize/DeclaredBitrate).
Zero Duration Segment	triggers if zero duration segment with segment size less than 564 bytes (three TS packets) is detected. If the segment duration is not declared, then the size of each downloaded segment is validated. However, if the downloaded segment size (content-length) is equal to zero, then regardless of its duration the “Bad Segment Size” event triggers.
Segment Downloaded	triggers if the probe successfully downloads yet another segment. Download IP address, HTTP response headers, timings of connection to the server, download time and date, caption, size, duration, and sequence number of the segment are registered. Additionally, the probe detects presence of the #EXT-X-INDEPENDENT-SEGMENTS tag in Master or Media playlists, and monitors if the segment starts with the IDR frame: “Ok” — the segment starts with the IDR frame; “Error” — the segment does not start with the IDR frame; “Unknown” — the probe fails to identify a frame the segment starts from.
Segment duration exceeds TARGETDURATION	triggers when the segment duration exceeds the EXT-X-TARGETDURATION value declared in the Media playlist. For HLS only.
Start With non-IDR Frame	a segment starts with a non-IDR frame. Analysis of encrypted segments (decryption keys are not accessible) is unavailable. Enabling of video analysis options in the Add Task form is not required.
Interlaced Video	a segment has interlaced video stream. Analysis of encrypted segments (decryption keys are not accessible) is unavailable.
Curl Error	error codes returned by the libcurl module when establishing a connection to an HTTP server. Used for various HTTP-based protocols. For more details see libcurl project.
HTTP Error	errors that occur while downloading of HLS and DASH objects (playlists, keys, segments). The HTTP error code is returned.

System Errors

Name	Description
Video Buffer Overflow	system low performance results in buffer overflow and video data cannot be timely analyzed by a probe. The system starts dropping video data before decoding. The data is dropped after TR 101 290 analysis and bitrate calculation; thus, the error does not influence the results of stream integrity analysis. This statement is also applicable to OTT, data drop before decoding does not influence calculation of segments download rate and detection of OTT errors. The Video Buffer Overflow error occurs only if QoE options are enabled in a task (i.e. video decoder is used).
OTT Buffer Overflow	system low performance results in OTT buffer overflow with downloaded segments that cannot be timely analyzed by a probe. The system starts skipping segments to avoid RAM overflow.
Task Crash Detected	a child process analyzing the stream has been restarted by the parent process, because no reply was received within 10s. Parent process monitors the tasks (child processes) performance and in case of critical error restarts the tasks with backward recovery.

Statistics

Name	Description
Open Alarms	currently registered alarms are displayed as colored cards. A card color corresponds to the severity level. A number on the card specifies the amount of active alarms of a certain severity level.
Severity levels statistics	number of alarms of the particular level and their total duration considering alarm overlapping for the selected monitoring period (15 minutes or last 24 hours). Statistics is available for the all severity levels.
Total Alarms	number of alarms of the particular level and their total duration considering alarm overlapping for the selected monitoring period (15 minutes or last 24 hours).
BadSource Alarms and States	number of registered BadSource alarms and states. Statistics presents their total duration for the selected monitoring period (15 minutes or last 24 hours).
Monitoring Time	monitoring duration for the selected period (15 minutes or last 24 hours) counted from the task analysis start and paused when a task is stopped or a probe is stopped or restarted.
QoS Availability	percentage of QoS availability is calculated as a ratio of total monitoring time minus QoS error duration to total monitoring time.
QoE Availability	percentage of QoE availability is calculated as a ratio of total monitoring time minus QoE error duration to total monitoring time.
Total Availability	percentage of total availability is calculated as a ratio of total monitoring time minus QoЕ+QoS error duration to total monitoring time.