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Professur Kommunikationsnetze
Chair of Communication Networks

ISAAR - Internet Service quality Assessment and Automatic Reaction

In order to achieve acceptable service quality, the broad spectrum of Internet services requires differentiated handling and forwarding of the respective traffic flows in particular within increasingly overloaded mobile networks. The 3GPP procedures allow for such service differentiation by means of dedicated GPRS Tunnelling Protocol (GTP) tunnels, which need to be specifically set up and potentially updated based on the client initiated service traffic demand. The SDN enabled QoE monitoring and enforcement framework for Internet services ISAAR (Internet Service quality Assessment and Automatic Reaction) augments existing quality of service functions in mobile as well as software defined networks by flow based network centric quality of experience monitoring and enforcement functions. The framework is meant to work with and without 3GPP support. Also the possibilities for QoE enforcement are variable and depending on the functions which are provided by the observed network.

Video example: Test video with embedded monitoring diagram.


QMON - The QoE monitoring component within the ISAAR architecture

Key characteristics of QMON:
  • QoE monitoring is based on precise play out buffer fill level estimation within the network for the client device (smartphones, tablets or PCs)
  • Fill level estimation is based on round trip time measurement and playout-timestamp extraction.
  • The algorithm has been developed and published since 2010.
  • TCP based progressive downloads are detected and monitored - based on TCP ACKs for increased precision.
  • typical Internet services covered include: Youtube, podcasts, ZDF mediathek, etc.
  • QMON is implemented in C++ under the BSD license
  • The fill level calculation is either based on every TCP segment or "jumps" through the stream without quality impairments for processing speed-up. This combined algorithm has been published and deployed since 2011.
  • QMON operates either in online mode (real-time monitoring) or on pcap traces (offline monitoring)
  • Field test are continously performed in production networks - mainly HSPA and LTE networks of German operators
  • supported media containers and codecs:
    • FLV
    • MP4 (e.g. with h.264)
    • WebM (e.g. with VP8)
  • supported video formats/resolutions:
    • SD e.g. 240p, 360p, 480p
    • HD e.g. 720p, 1080p