WITS: Auckland VII

This is a mostly continuous 15 and a half hour GPS-synchronized ATM cell header trace captured using a DAG 3 card at the University of Auckland. As this is an ATM cell header capture, there are no IP headers and, in fact, very little information at all aside from a timestamp and most (but not all) of the ATM cell header.

The tap was installed at an OC3c link carrying various Classical-IP-over-ATM, LANE and POTS services. All cells were captured and immediately processed to extract only the timestamp and header data. All other information was discarded. Details regarding the types of traffic represented by each VPI/VCI were saved, but our copies of the traces do not appear to have come with that information.

A few of the traces in the set appear to have been prematurely aborted. We do not know whether these breaks were caused by a hardware fault or a network failure as there does not appear to be any documentation that explains them. Additionally, we cannot produce any graphs or counts of the traffic represented by the traces due to the lack of any such detail in the records.

Each trace file is named using the following format: yyyymmdd-HHMMSS-[direction].hdr.gz. The time and date refers to the local time when the capture was started. The direction refers to which half of the link is contained within the trace. Traditionally, Auckland traces have set direction 0 as traffic coming into the University and direction 1 as traffic originating from the University. However, without IP headers in the trace we have not been able to confirm that this still holds for this traceset.

The recommended method for processing these traces is to use Libtrace, which we have developed. There are a number of tools included with libtrace such as a packet dumping utility, a trace format converter (for example, to convert to pcap), a trace splitting/filtering tool and a few statistic generators. We suggest you examine the Libtrace Wiki for more details on the Libtrace tools and the library itself.

Acknowledgements: Some of the information presented on this page has been sourced from the NLANR page about this traceset.