[Theme]Measurement and Analysis of IPv6 Networks Using IP Meter with a GPS Timestamp Component back
Satoshi KATSUNO Post:TAO Tokyo IPv6 Research & Operation Center
Author:Satoshi KATSUNO
Internet Traffic measurement is the key technology to maintaining the network performance and providing various services for users. Recently, IETF's working group has proposed a framework for IP performance metrics. Project Surveyor and WIDE MAWI WG have created their measurement infrastructure. Since the bandwidth of backbone network is increasing rapidly, gathering information on network behavior is becoming difficult. NLANR and CAIDA are developing large-scale data collection systems and various tools to analyze network data. Several other projects have performed their research and development activities on measurement and analysis of high-speed networks.


2.Overview of our research activity
To measure the traffic of high-speed networks, e.g. the JGN IPv6 network, a hardware-based IP meter system with GPS (Global Positioning System) timestamp unit was developed. This system is employed for measurement and analysis of various networks.

In recent, video and audio applications are becoming widely used in addition to data transfer applications such as WWW, and quality assurance for quality of service in network are needed. Because IP packet transmission delay and jitter are significant parameters for the quality of application services, the measurement of these parameters is becoming increasingly important.

Generally, the interval of two succeeding heads of packets becomes smaller in high-speed network. Therefore, it becomes difficult to measure the correct timestamp information of transmitted packets. For example, 0.5-12 micro-second precision is required for measurement of 1 Gbps networks. However, the experimental results show that software-based traffic measurement equipments cannot handle 1 micro-second order timing information.

To meet this requirement, a high-speed IP meter system, which receives high-precision GPS timestamp, was developed. With this system, the measurement of IP packets with 100 nano-second order timestamp information was enabled. This system has been employed for various measurement and analysis of various IPv6 networks.

3.Detail of the system

Figure 1 shows the IP meter system with the GPS timestamp unit. This system was implemented based on a Hitachi GR-2000 router. It has a GPS unit in its extension slot. This unit receives signal from GPS satellites, and it performs measurement of traffic with correct timestamp information.

IP meter system
[Figure 1. IP meter system]


4.Results of our research

With the IP meter system, traffic measurement and analysis for various networks including JGN were performed. The traffic measurement activities are as follows:
  • Measurement of IPv6 digital video traffic at JGN symposium 2002
  • Measurement and analysis of packet delay in commercial IPv6 ADSL access networks
  • Measurement of IPv4/IPv6 traffic at IETF meeting in Yokohama
  • In this article, as a part of our measurement, results of measurement and analysis of packet delay between JGNv6 and an IPv6 ADSL access network is presented
Recently, commercial or experimental IPv6 access services have been provided on ADSL. Measurement of strict one-way packet delay was performed on ADSL access network. The configuration of the measurement is in Figure 2. Our monitoring points are located on the ADLS end user access host and a host at the JGN IPv6 network. Two IP meters are synchronized to GPS clocks and accurate one-way packet delay can be obtained by capturing UDP packets which are transmitted between measurement points.

As the result of our measurements, in asymmetrical network as ADSL, upstream packet delay and downstream packet delay varies in their values and characteristics.

The average packet delay of downstream packet is always smaller than that of upstream packets. Especially, downward jitter at nighttime becomes larger.

Figure 2
[Figure 2]


5.Impacts of our research activity
The purpose of our research activity is to reveal various network characteristics by using collect timestamp information. Due to the improvement of high-speed backbone network and various multimedia services which are provided in the Internet, the precise measurement of internet is becoming important. The results of this research activity are useful for network management and operation.



In this article, research activity on measurement and analysis of the Internet traffic using IP meter system with GPS timestamp unit was introduced. The detail of IP meter system was described and the results of our experiments on traffic measurement were presented. We are going to proceed with this research and development for advanced.

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