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System and Signal Monitoring for IPTV Set-Top-Box Systems Dávid Károly Tivadar Szemethy Árpád Bakay
The need for end   to   end monitoring <ul><li>Telcos are rolling out IPTV </li></ul><ul><li>3-play </li></ul><ul><li>Must...
Contents <ul><li>IPTV Network Architecture </li></ul><ul><li>Set top box architecture </li></ul><ul><li>MPEG-2 Transport S...
IPTV Content Delivery System Customer Premises VoD Cluster Headend Core Network STB IAD Access Network
Set top box architecture <ul><li>Hardware </li></ul><ul><ul><li>RISC GPP </li></ul></ul><ul><ul><li>Video decoding with DS...
Transport Stream Monitoring <ul><li>Raw UDP encapsulation </li></ul><ul><li>TS packets </li></ul><ul><ul><li>Header, Adapt...
Transport Stream Monitoring (II) <ul><li>Characteristics to measure </li></ul><ul><ul><li>Bandwidth, Packet loss </li></ul...
Naive implementation <ul><li>AF_PACKET raw sockets </li></ul><ul><li>Packet filter </li></ul><ul><li>Not feasible </li></u...
Packet capture inside the kernel <ul><li>Register a callback </li></ul><ul><ul><li>Dev_add_pack() </li></ul></ul><ul><ul><...
User mode portion <ul><li>SNMP agent based on Net-SNMP </li></ul><ul><ul><li>Turn on/off with SNMP row creation/deletion <...
Test results <ul><li>Tests conducted in two settings </li></ul><ul><ul><li>Corporate intranet </li></ul></ul><ul><ul><li>I...
Further findings <ul><li>PCR behavior is codec-dependent </li></ul><ul><li>Usefulness of diagnostic parameters </li></ul><...
Conclusions and future work <ul><li>Interpreting acquired data </li></ul><ul><ul><li>Further experiments are needed </li><...
Thank you for your attention! <ul><li>Dávid Károly </li></ul><ul><li>David.Karoly  at  netvisor  dot  eu </li></ul>
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IPTV Set-top box monitoring

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Dávid Károly, Tivadar Szemethy, Árpád Bakay: "Signal and System Monitoring for IPTV Set-top Box Systems", in Proc. RCEAS'07, 2008.

Published in: Technology, Business

IPTV Set-top box monitoring

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

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