system and signal monitoring for iptv set-top-box systems
DESCRIPTION
System and Signal Monitoring for IPTV Set-Top-Box Systems. Dávid Károly Tivadar Szemethy Árpád Bakay. The need for end to end monitoring. Telcos are rolling out IPTV 3-play Must ensure high availability, QoS, QoE Importance of CPE monitoring Last mile problems - PowerPoint PPT PresentationTRANSCRIPT
System and Signal Monitoring for IPTV Set-
Top-Box Systems
Dávid Károly
Tivadar Szemethy
Árpád Bakay
The need for end to end monitoring Telcos are rolling out IPTV
3-play
Must ensure high availability, QoS, QoE
Importance of CPE monitoringLast mile problems
STB’s lack diagnostic interface
Contents
IPTV Network Architecture
Set top box architecture
MPEG-2 Transport Stream Monitoring
Implementation
Test results
Conclusions, future work
Customer PremisesVoD Cluster
Headend
IPTV Content Delivery System
Core Networ
k
STB
IAD
Access Network
Set top box architecture Hardware
RISC GPP Video decoding with DSP or ASIC Ethernet, SCART, IR interface
Software Embedded Linux Media player User interface, browser
Transport Stream Monitoring Raw UDP encapsulation
TS packetsHeader, Adaptation Field
PID’s, metadata, Elementary Streams
Timestamps: PCR, PTS, DTS
Transport Stream Monitoring (II) Characteristics to measure
Bandwidth, Packet loss Also per stream type (audio/video/metadata)
UDP-level Jitter, inter-arrival gap min/max/avgPCR characteristics
PCR Jitter PCR discontinuities, missing PCR
Naive implementation AF_PACKET raw sockets Packet filter Not feasible
InaccurateEats up CPU cycles, UI responsiveness is
hindered10 Mbps HDTV stream: 23% CPU usage
Packet capture inside the kernel Register a callback
Dev_add_pack()
Callback runs in softirq context
Gets skbuf with timestamp
Eliminates kernel to user copies
Results can be accessed via /proc filesystem
User mode portion SNMP agent based on Net-SNMP
Turn on/off with SNMP row creation/deletion Sends TRAP in cast of threshold violation
Repeatedly reads the proc-file Only aggregated values: averages, counters Read once per second
Can be remotely queried, turned on/off Also provides diagnostic parameters
Load average, free memory CPU load imposed by SNMP agent
Test results Tests conducted in two settings
Corporate intranet IPTV test network of a service provider
The approach is workable No extra CPU load imposed (even with HDTV, up to
10 Mbps) Accurate measured values, compared to a standalone
PC probe
Further findings
PCR behavior is codec-dependent
Usefulness of diagnostic parametersHeadend misconfiguration causes small
subtle errors (like metadata discontinuity)
This results in high STB load and frequent
reboots
Conclusions and future work Interpreting acquired data
Further experiments are needed Compare metrics with opinion score Data mining
Other parameters worth analyzing MDI per RFC1889 IGMP channel zap delay
Integrate into IAD or bridging probe
