IPEX is a network of measurement servers that collect IP packet header traces (not payloads) and traffic statistics for the use of the Network Modeling and Simulation Community. The measurement infrastructure consists of collectors at participating organizations, central operations administration in an automated, "lights out" operation, and a secure central data access server. Organizations offering data have varying traffic profiles, and range across small to large information-intensive service providers and networks. Traffic traces and summaries hae been available to NMS researchers since August 2002. Datra collection and access to the database is ongoing.

The measurement strategy is to collect traffic data continuously for a defined length of time each day. Data at each site are processed on the fly to assure privacy protection and security. The collector at each site write the data collected over specfied intervals into separate files. Along with file of the detailed data is a file containing a statistical summary of the corresponding data.

All the summary-files are transmitted to the central server at Telcordia, to be held for long periods and made available to authorized users on request. Each local site may archive all its detailed data-files in accordance with the local policy. In addition each day the detailed data-file for a randomly chosen interval is sent from each site to the central server. Furthermore, each site can schedule the transmission to the central server of any set of the detailed interval files of special interest. We estimate that each monitor could collect up to 3 gigabytes of compressed data per day, assuming a 3:1 compression ratio.

Building on the experiences of other measurement projects, the data collection systems consist of standard low cost hardware optimized for consistency, reliability, safety, low maintenance and remote management.

Software consists of the NIMI platform and custom scripts for basic operation. IP addresses obfuscated. Administration is centrally managed, to the extent possible, for ease of participation and for safety.

The operations are supported by Telcordia Technologies with assistance from the Stanford Linear Accelerator (SLAC). Access to the data and to the infrastructure is a service to the NMS community. The service is an interface to search and browse trace data for specific metrics and to obtain by download the trace data files and summary for detailed analysis. For access authorization please contact Allen Mcintosh at: mcintosh at research.telcordia.com.

The measurement infrastructure is available for both data collection and scheduled experimentation. NMS Program participants are invited to mount probes at their intstitutions. "Constructing An IPEX Probe: Hardware and Software Instructions", describes the recommended configuration and has contact infromation for assistance. At present, collaborative work with NMS researcher is underway on areas of active measurements for data compression for traffic flow control in online simulation (with SAIC) , and algorithms for detection of denial of service attacks (with Rice University).

The project has two mailing lists. The first list is for general discussion, and has an open subscription policy. The address of the list is ipex at research.telcordia.com. Anyone wishing to subscribe to the list should send e-mail to ipex-request at research.telcordia.com with the word "subscribe" as the subject. The second list is intended for discussion of probe administration and security issues. This list is closed, i.e. additions to the list are not automatic. Anyone wishing to be placed on the list should send e-mail to ipex-admin-request@research.telcordia.com with the word "subscribe" as the subject.

Comments, questions or suggestions can be made via the mailing list or directly to:

Charles Brownstein at: cbrownst at cnri.reston.va.us or to

K. R Krishan at: krk at research.telcordia.com or to

Created November 1, 2001 Last Modified July 31, 2003