Troubleshooting IPTV Using The Clearsight Network Analyzer

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Troubleshooting IPTV Using The Clearsight Network
Analyzer
ClearSight Networks, Inc.
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The Presenter

• Mike Pennacchi
• Owner Network Protocol Specialists, LLC
• 10 years professionally troubleshooting networks
• Instructor at InterOp for 9 years
• Use the ClearSight Analyzer as part of our
  consulting business

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Agenda
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Troubleshooting Video Networks
Video Troubleshooting
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Video Traffic Analysis

• Measuring Video Quality
• Streaming methods
• CODECs
• Impact of impairments
• VQFactor
• IPTV and Multicast Technologies
• IP Multicasting
• Channel Zapping

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Video Traffic Analysis

• Streaming Methods
• Reliable
• Transmission Control Protocol
• Works well for Video on Demand
• Missing frames are retransmitted
• Viewer creates their own connection to the video
  server
• Bandwidth intensive
• Good video quality

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Video Traffic Analysis
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Video Traffic Analysis

• Streaming Methods
• Unreliable
• User Datagram Protocol
• No retransmissions
• Works for both Video on Demand and Live video
• Packet loss and Jitter result in degraded video
  quality
• One stream per viewer, bandwidth intensive

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Video Traffic Analysis
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Video Traffic Analysis

• Streaming Methods
• Multicast
• User Datagram Protocol
• No retransmissions
• Works for Live video
• Packet loss and Jitter result in degraded video
  quality
• One stream for all viewers, conserves bandwidth

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Video Traffic Analysis

• CODECs
• Responsible for Encoding and Decoding the video
  stream
• CODEC used determines the about of bandwidth for
  each stream.
• CODEC also determines the sensitivity to Jitter
  and Packet Loss

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Video Traffic Analysis

• Supported CODECs
• H.264 (Baseline, Main, Extend)
• MPEG2-TS (payload type 14)
• MPEG2 layer II (payload type 33)
• MPEG4
• ASF (Windows Media Advanced System format)
• iLBC (internet Low Bit Rate Codec)
• JPEG (411, 422, 111)
• H.263 (Mode A and Mode B)

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Video Traffic Analysis

• Streaming Protocols
• Realtime Streaming Protocol (RTSP)
• Responsible for setting up the stream
• Contains commands and responses
• Realtime Protocol (RTP)
• Header for the data frames
• Contains sequence numbers and timestamps to help
  determine frame loss and jitter

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Video Traffic Analysis

• RTP and RTSP

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Video Traffic Analysis
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Video QoS measurement

• VQFactor
• Supported in ClearSight 6.0
• Resulting metrics are represented as current CSA
  MOS/R-Value stats
• Displayed in QoS Report
• Quality related alarms are supported to alert
  when degradation occurs

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VQFactor Stats
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MPEG Statistics

• MPEG Stats
• Three Types of Frames
• I Frames Contain the entire screen image
• P Frames Predicted from past I or P frames
• B Frames Predicted from past and future I or
  P frames

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MPEG Statistics
I-Frame Stat
P-Frame Stat
B-Frame Stat
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Video quality alarms

• Alarms
• Alarms can be configured to trigger on multiple
  impairments
• Jitter
• Packet Loss
• MOS Score
• Based on configured severity, the appropriate
  action will be taken
• E-Mail
• SNMP Trap

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Video quality alarms
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Video quality report

• Video Quality Report
• As with the VoIP Quality Report, reports can be
  produced for IPTV video streams
• The report will help identify the type of
  impairment

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Video quality report
VQFactor
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Channel Zapping
Channel Zapping
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Channel Zapping

• Channel Zapping
• Occurs when view changes channels from one
  multicast stream to another
• Client sends IGMP Leave for previous stream
• Client sends IGMP Join for new stream

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Channel Zapping

• Channel Zapping Issues
• Channel Change Latency
• Time between when the IGMP Join is sent and when
  the multicast stream is received
• Very short if stream is already near router
• Long if reverse path must be built to the
  multicast source

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Channel Zapping
Receive Rate(pps)
Leave Ch.2(S1,G1)
Join Ch.3(,G2)
Leave Ch.3(,G2)
Join Ch.4(,G4)
Join Latency
Leave Latency
Channel3 (,G3) Stream
Channel4 (,G4) Stream
Channel2 (S1,G2) Stream
Time (t)
Channel Overlap
Channel Gap
Channel Change latency
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Channel Zapping

• Channel Zapping Issues
• Channel Gap
• Time between when the view stops receiving one
  channel and begins receiving the next
• Most likely to occur each half hour when shows
  change
• Likely to occur during commercials
• Gap can result in blank screen for viewer

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Channel Zapping

• Channel Zapping Issues
• Channel Overlap
• Multicast stream is still being sent for the
  previous channel due to IGMP Leave latency
• New multicast stream is being received at the
  same time
• Uses twice the bandwidth

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Channel Zapping
Channel Overlaps
Ch.4
Ch.1
Ch.3
Ch.2
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Troubleshooting Examples
Troubleshooting Examples
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Thank you
Clearsight Networks