ClearSight Networks CONFIDENTIAL 1 Troubleshooting IPTV Using ...

ClearSight Networks CONFIDENTIAL1

Troubleshooting IPTV Using The Clearsight

Network Analyzer

ClearSight Networks, Inc.


The Presenter

• Mike Pennacchi• – Owner Network Protocol

, Specia lis ts LLC• 10 years profess iona lly

troubleshooting ne tworks• 9 Ins tructor a t Inte rOp for

years• Use the ClearSight Analyzer

as part of our consultingbus iness


Agenda


Troubleshooting Video Networks

Video Troubleshooting


Video Traffic Analysis

• Measuring Video Quality– Streaming methods–CODECs– Impact of impairments–VQFactor

• IPTV and Multicas t Technologies– IP Multicas ting– Channe l Zapping



• Streaming Methods–Reliable• Transmiss ion Control Protocol• Works well for Video on Demand• Miss ing frames are re transmitted• Viewer crea tes the ir own connection to the

video server• Bandwidth intens ive• Good video quality



• Streaming Methods–Unre liable• User Datagram Protocol• No re transmiss ions• Works for both Video on Demand and Livevideo• Packet loss and J itte r result in degraded

video quality• , One s tream per viewer bandwidthintens ive



• Streaming Methods–Multicas t• User Datagram Protocol• No re transmiss ions• Works for Live video• Packet loss and J itte r result in degraded

video quality• , One s tream for a ll viewers conservesbandwidth



• CODECs– Respons ible for Encoding and

Decoding the video s tream– CODEC used de te rmines the about of

.bandwidth for each s tream– CODEC also de te rmines the sens itivity

to J itte r and Packe t Loss



• Supported CODECs– .264 ( , , )H Base line Main Extend– 2- ( : 14)MPEG TS payload type– 2 ( : 33)MPEG layer II payload type– 4MPEG– ( ASF Windows Media Advanced Sys tem

)format– ( )iLBC interne t Low Bit Ra te Codec– (411, 422, 111)JPEG– .263 ( )H Mode A and Mode B



• Streaming Protocols– ( )Realtime Streaming Protocol RTSP• Respons ible for se tting up the s tream• Conta ins commands and responses

– ( )Realtime Protocol RTP• Header for the da ta frames• Conta ins sequence numbers and

times tamps to he lp de te rmine frame loss and jitte r



• RTP and RTSP


Video QoS measurement

• VQFactor– 6.0Supported in ClearSight– Resulting metrics a re represented as

/ - current CSAMOS R Value s ta ts– Displayed in QoS Report– Quality re la ted a la rms are supported to

a le rt when degrada tion occurs


VQFactor Stats


MPEG Statistics

• MPEG Sta ts– Three Types of Frames• – – I Frames Conta in the entire screenimage• – – P Frames Predicted from pas t I or Pframes• – – B Frames Predicted from pas t and

future I or P frames


MPEG Statistics

I-Frame Stat

P-Frame Stat

B-Frame Stat


Video quality alarms

• Alarms– Alarms can be configured to trigger on

multiple impairments• J itte r• Packet Loss• MOS Score– , Based on configured severity the

appropria te action will be taken• -E Mail• SNMP Trap


Video quality alarms


Video quality report

• Video Quality Report– , As with the VoIP Quality Report reports

can be produced for IPTV videos treams

– The report will he lp identify the type ofimpairment


Video quality report

VQFactor


Channel Zapping

Channel Zapping


Channel Zapping

• Channe l Zapping– Occurs when view changes channe ls

from one multicas t s tream to another– Client sends IGMP Leave for previouss tream– Client sends IGMP Join for new stream


Channel Zapping

• Channe l Zapping Issues– Channe l Change Latency• Time between when the IGMP Join is sent

and when the multicas t s tream is rece ived• Very short if s tream is a lready near router• Long if reverse pa th must be built to the

multicas t source


Channel Zapping

ReceiveRate （ pps ）　

Time （ｔ）

Channel2（ S1,G2 ） Stream

Channel3（＊ ,G3 ） Stream

Channel4（＊ ,G4 ） Stream

Channel Change latency

Channel Gap

Leave Ch.2 （ S1,G1 ）

Join Ch.3（ *,G2 ）

Leave Ch.3（ *,G2 ）

Join Ch.4（ *,G4 ）

Channel Overlap

Join Latency

Leave Latency


Channel Zapping

• Channe l Zapping Issues– Channe l Gap• Time between when the view s tops

rece iving one channe l and begins rece iving the next

• Most like ly to occur each ha lf hour when shows change

• Like ly to occur during commercia ls• Gap can result in blank screen for viewer


Channel Zapping

• Channe l Zapping Issues– Channe l Overlap• Multicas t s tream is s till be ing sent for the

previous channel due to IGMP Leavela tency• New multicas t s tream is be ing rece ived a t

the same time• Uses twice the bandwidth


Channel Zapping

Ch.1 Ch.2 Ch.3 Ch.4

Channel Overlaps


Troubleshooting Examples

Troubleshooting Examples


Thank you

Clearsight Networks

ClearSight Networks CONFIDENTIAL 1 Troubleshooting IPTV Using ...

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