Monitoring and Measuring IP Media Networks

Presenters : Michael Waidson - Tektronix

Year : 2019

dlp_document_download : C U R A T E D B Y I P S H O W C A S E T H E AT E R AT N A B – A P R I L 8 -11 , 2 01 9 Monitoring and Measuring IP Media Networks Michael Waidson, Application Engineer Tektronix, Inc. Media Networking Monitoring • Video ST 2110 -20 ‒ Multicast Address, Port, Payload Type • Audio ST 2110 -30 ‒ Multicast Address, Port, Payload Type • Data ST 2110 -40 ‒ Multicast Address, Port, Payload Type • SMPTE 2059 -2 PTP Profile 2 Need some strategy for identification of flows • ‒ 239.20.xxx.xxx, 50020, 96 • ‒ 239.30.xxx.xxx, 50030, 97 • ‒ 239.40.xxx.xxx 50040, 100 • Domain, Message Rates Troubleshooting Basics 3 • Check Cables ‒ Single or Multi Mode • Check SFPs ‒ 1G, 10G, 850nm, 1310nm • Check Port ‒ Up or Down 4 IP Status – Checking Addresses • Check Following ‒ Bitrate ‒ Payload ‒ Addresses ‒ PTP Domain ‒ Sequence Errors ‒ RTP Clock ‒ RTP Marker Frequency Checking Syntax of decoded streams 5 • Check Following ‒ Layer 5 RTP ‒ Marker Bit ‒ Payload Type ‒ Sequence No. ‒ Time Stamp • Can Video & Audio be decoded? Packet Transmission • Asynchronous streams can produces jitter or out of order packets 6 Timestamp xxxxx Sequence Number yyyyy Packet 3 Packet 2 Packet 1 Packet 4 Packet 5 Δt Packet 5 Packet 3 Packet 2 Packet 4 Δt Packet 1 Sender Δt Δt Network Cloud Receiver Δt + aΔt Δt Δt + bΔt Δt + cΔt Δt + dΔt Δt + eΔt Packet Interarrival Time (PIT) • Monitor packet arrival time • Determine out of order packets • Determine Reconstructed Path Errors 7 PIT Histogram • Characteristic signature of device • Narrow Linear • Gapped • Wide Linear 8 ST 2110 Stream Timing 9 PTP Reference Clock 2110 Enabled Device Internal Clock 1 6 3 4 2 2 5 6 0 6 7 2 2 8 3 2 Zero Offset Zero Offset Video Datagram Audio Datagram 0 6 7 2 2 8 3 2 RTP Timestamp 1 6 3 4 2 2 5 6 0 6 7 2 2 8 3 2 1 6 3 4 2 2 5 6 90kHz Clock 48kHz Clock ST 2110 Stream Timing 10 Timing Display • Check PTP Lock • Compare IP video input to PTP • Can compare analog reference to PTP 11 Stream Timing Measurement • Vid PTP offset ‒ Timing of video as received against PTP • Vid RTP offset ‒ Timing of video as received relative to embedded RTP timestamp 12 Network Compatibility Model - Sender • Sender Packet enters a leaky bucket of infinite capacity • The bucket drains a packet ever T DRAIN seconds if a packet is available • C INST instantaneous number of packets in the bucket, should never exceed C MAX 13 C MAX C INST Drain Rate =1/T DRAIN ST2110 Sender Virtual Receiver Buffer Model • Packets from Sender enter a leaky bucket of capacity VRX FULL • Packets enter and leave instantaneously • VRX FULL bucket drain packet j at the Packet Read Schedule TPR J • Sender shall ensure bucket does not overflow • Sender shall ensure packet J is available no later than TPR J does not underflow 14 Packet j drains At time TPR J ST2110 -20 Sender VRX FULL (packets) ST 2110 - 21: Types of Senders 15 • Narrow (N): C max = 4 VRX Full = 8 • Wide (W): Cmax = 16 VRXFull = 720 • Narrow Linear (NL) : C max = 4 VRX Full = 8 Wide - Linear 16 • Do we have a problem ? • Packet Read Schedule ? • Needs to be changed to Wide Linear • Meets requirements for Wide Linear C U R A T E D B Y I P S H O W C A S E T H E AT E R AT N A B – A P R I L 8 -11 , 2 01 9 Thank You Michael Waidson, Tektronix, Inc. michael.h.waidson@tek.com