MobiLib-USC: Traces from the USC wireless LAN
This webpage provides a brief description of the USC wireless LAN traces.
These are measurements made on the university
park campus at the
University of Southern California (USC)
(click here
for the wireless coverage map). The traces were
collected from approximately 400 access points (mostly on campus)
through 79 switch ports (corresponding roughly to building level
granularity), with over 4500 users. This page gives users access to the
traces.
- Application to access the trace data:
to access the actual data please contact Wei-jen Hsu
(weijenhs@usc.edu) or Ahmed
Helmy
(helmy@usc.edu), including your
preferred username and password to access the data in your mail.
- For the actual trace data and analysis code click here [you will need
a username and password through the application process below]
What is available through the USC trace?
The following two types of traces are available: (a) raw traces and
(b) processed traces.
(A) Raw traces:
- Session traces: These traces are logs for timestamps of (start|stop)
of VPN sessions. At USC, wireless users must establish connections to a
VPN server before they can use the network. Hence the session log contains
periods of users potentailly using the network, with its MAC address and
assigned (dynamic) private IP addresses.
- DHCP log: The DHCP log contains the private IP assignments to MAC
addresses.
- Traps: The trap log contains the (switch port, MAC address)
association when the user is online. However, if a MAC re-appears at the
same switch port when it was last online, the trap log may NOT record this
information. Hence trap log must be used in conjunction with session log
to discover all association sessions. [We also have trap records for
the past 2 years, available upon request.]
- Flow size log: The log of data flow sizes (in KB) and its
source/destination IP address/port. Due to the large size of this data
(hundreds
of MB per day) it cannot be available online. Please contact us if you are
interested in this data.
(B) Processed traces:
From the above raw traces it is possible to find out user locations (at
per switch port granularity, which roughly corresponds to buildings on
campus) when they are online. We have such processed trace for the time
period of Apr. 20, 2005 to May. 19, 2005. (This is the trace we used in
the IMPACT paper listed below.) We shall also make the program
code for trace processing and analysis available.
Time frame for trace collection
These traces were collected between Apr. 19, 2005 and Aug. 8, 2005. We
also have 'Traps' measurements starting from Dec. 2003 through Aug.
2005.
On Aug. 9, 2005 we stopped collecting the trace due to changes in our
campus network, and we shall resume trace collection after these changes.
Terms and Conditions
You must agree to the following terms to use the USC trace data:
- You may not redistribute the traces to other people outside your
research group (one shared account for one research group is OK). If you
know other researchers who may be interested in using this data, please
distribute the pointer to this page, but NOT the username/password.
- While we have made effort to avoid errors in the process of
collecting and manipulating the traces, we cannot guarantee complete
correctness in both the traces and codes used. The users of the traces and
codes should be aware that we do not guarantee the traces or codes are
free of bugs, and assume some risks if you use them 'as is'.
- Any futher work derived from the trace data should not make the MAC
addresses visible in plain text. Instead, please use self-defined IDs to
identify individual nodes if you have to do so in the work.
Related publication and websites
Acknowledgements
This work was funded in part through the NSF CAREER Award 0134650.
We would like to thank Brian Yamaguchi and Carl Hayter at USC Information
Service Division (ISD) for helping us collect the WLAN traces on the
USC
campus for the past 2 years.
This website is maintained by Wei-jen Hsu (weijenhs@usc.edu) and
Ahmed Helmy (helmy@usc.edu).
Last updated: Aug. 12, 2005.