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RTP monitoring with IPFIX

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Experiments : Bit Rate and Packet Rate. 2006/10/28. Hyeongu Son (DN Lab - CNU) KyuShu University ... packet loss, packet rate, bit rate. Future Work ... – PowerPoint PPT presentation

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Title: RTP monitoring with IPFIX


1
RTP monitoring with IPFIX
  • Hyeongu Son
  • jeongil9_at_cnu.ac.kr
  • Data Networks Laboratory
  • Dept. of Computer Science and Engineering
  • Chungnam National University

2
Introduction
  • Traffic Monitoring
  • Account user traffic
  • Check QoS (Packet loss, Delay, etc)
  • Flow-based traffic monitoring
  • popular, easy, cheap and reduced data
  • Whats the purpose?
  • to provide QoS of multimedia streaming traffic
    by monitoring RTP
  • to measure QoS metrics such as delay, jitter,
    packet loss
  • to develop RTP monitoring tools supporting IPFIX
    in IPv6 networks

3
RTP Header
allow synchronization and jitter calculations
  • increase number by one for every RTP packet
  • be able to check dropped packet (packet loss)
  • determine sequence of packet
  • generate random number for the initial number

Version be usually set 2
payload type ( DV 123, MPEG2 33)
padding
CSRC Count
extension
Marker
0
31
18
Timestamp
Synchronization Source (SSRC) Identifier
4
MPEG 2 DV(IEC 61834) Traffic
  • The character of MPEG2 traffic in RTP
  • timestamp 1) somewhat different
  • 2) estimate and reduce any network-induced
    jitter
  • 3) synchronize relative time
    drift
  • payload contain an integral number of MPEG
    transport packets
  • Header extension
  • The Character of DV traffic in RTP
  • Dynamically assign the payload type
  • All packets have the same timestamp (within the
    same video frame)
  • Frame change based on a difference in the RTP
    timestamp
  • Not necessary additional payload-format-specific
    header

5
RTP Plugin Flow Format in nProbe (1)
  • Already defined field type for RTP monitoring

6
RTP Plugin Flow Format in nProbe (2)
  • add 4 field type such as next table

7
RTP Monitoring Method (1)
8
RTP Monitoring Method (2)
  • Flow Classifier
  • processes incoming packets with five-tuples
    (source/destination IP address and port number,
    protocol)
  • Flow Exporter
  • send flow-exporting pakcets to the flow
    collector that contains flow information
  • Flow Collector
  • receives IPFIX message and save the template and
    data record
  • Flow Analyzer
  • classifies only one flow which is the same
    5-tuples with the RTP as well as
  • typical port numbers
  • Flow Visualizer
  • show the analyzed data by graph and table

9
Experiments Test Environment
10
Experiments Test Environment
11
Experiments Test Environment
12
Experiments Monitoring Tool
  • Java program for RTP monitoring

13
Experiments Delay (1)
  • delay (current packet timestamp previous
    packet timestamp)
  • In case of DV, use NTP timestamp
  • calculated at just one flow
  • Originally, nProbe just has MAX delay value
  • added MIN and Average delay value in rtp plugin
  • look for MAX, MIN, Average delay between
    consecutive packets in nProbe
  • Ex) A flow has 1,000 packets. This flow has 999
    delay values.
  • This monitoring represent minimum, maximum
    and average delay value
  • between those values

14
Experiments Delay (4)
15
Experiments Delay (5)
16
Experiments Inter-arrival Jitter (1)
  • An estimate of the statistical variance of RTP
    data packet inter-arrival time
  • defined to be the mean deviation of the
    difference in packet spacing at
  • the receiver compared to the sender for a pair
    of packets
  • the method of calculating inter-arrival jitter
    (Referenced by RFC 1889)
  • 1) transit current time last time
  • 2) jitter sample(d) transit last transit
  • 3) d lt 0 ? d -d
  • 4) new jitter (d last jitter) / 16

17
Experiments Inter-arrival Jitter (2)
18
Experiments packet loss (1)
  • derived from sequence number
  • sequence number incremented for every RTP
    packet
  • Be able to know whether packet is dropped
    through sequence number
  • The method of packet loss calculation
  • temp current sequence number initial
    sequence number
  • packet loss temp amount of packets
  • if(packet loss lt 0) ? packet loss 0

19
Experiments packet loss (2)
20
Experiments Bit Rate and Packet Rate
21
Conclusion
  • A RTP traffic monitoring method
  • based on the IPFIX standard
  • through IPFIX information, we can get some data
  • Maximum, Minimum, Average Delay
  • inter-arrival jitter
  • packet loss, packet rate, bit rate
  • Future Work
  • measure DV traffic between Korea (Chungnam
    National University) and
  • Japan (Kyushu University)

22

Thank you Do you have any question?
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