WITS: Local ISP A-III

Trace Format PCAP file captured using tcpdump.
Volume on Disk 5 GB
Number of Traces 7
Capture Start (Local) Mon Dec 20 16:02:30 1999
Capture End (Local) Wed Jan 5 18:35:40 2000
Total Duration 13 Days, 5 Hours, 19 Minutes and 28 Seconds
Packets Captured 140 million
Total Traffic 43 GB
Contiguity Mostly contiguous - one trace lost to media corruption.
Snapping Method tcpdump snaplen was set to 100 bytes.
Rotation Policy Files were rotated every 20 million packets.
Anonymization None

This is a collection of traces taken at a New Zealand ISP using tcpdump on a Linux box located inside the ISP's internal network. Due to NDA requirements, we cannot disclose the name of the ISP, nor can we offer these traces for public download.

Each trace file is named using the following format: yyyymmdd-HHMMSS.tcpd.gz. The time and date refers to the local time when the capture was started. Both directions are contained within the single trace; however, the pcap format does not contain any information about a packet's direction so it is not possible to ascertain which direction a packet was travelling in the trace.

One of the traces that belonged to this set is not included in these pages, as the trace appeared to have been corrupted when we restored it from tape. The trace was 19991229-141228.tcpd.gz. We still have the corrupted version of the trace which contained approximately 14 million packets prior to the point where the trace was damaged, if required.

The previous traceset taken at this ISP used a script to synchronise the clock after every file rotation. This caused some overlap in trace start and end times. This overlapping is not present in this traceset but we do not know whether this is because clock synchronisation was not performed at all during the capture or because clock synchronisation was done in a better and less obvious fashion. The trace files themselves are rotated every 20 million packets, just as they were in the previous traceset. However, there is a gap of over a day between the first two traces in the set, which we cannot account for.

Timestamping within the traces themselves was taken using the system clock. As a result, the timing will be affected by clock drift and a lack of sub-microsecond accuracy, particularly considering that these traces were captured back in 1999. Timing accuracy that we take for granted now was not as readily available or widespread as when this traceset was captured.

The tcpdump snaplen for this traceset was set to 100 bytes, which is less than that used in the previous tracesets captured at this ISP.

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.

Name Local Start Time Duration Total Packets Compressed Size
19991220-160230.tcpd Mon Dec 20 16:02:30 1999 43:54:47 20 million 770 MB
19991223-151941.tcpd Thu Dec 23 15:19:41 1999 40:06:00 20 million 818 MB
19991225-072541.tcpd Sat Dec 25 07:25:41 1999 58:01:23 20 million 781 MB
19991227-172704.tcpd Mon Dec 27 17:27:04 1999 44:45:23 20 million 764 MB
19991231-080346.tcpd Fri Dec 31 08:03:46 1999 51:00:01 20 million 749 MB
20000102-110347.tcpd Sun Jan 2 11:03:47 2000 46:43:37 20 million 767 MB
20000104-094725.tcpd Tue Jan 4 09:47:25 2000 32:48:15 20 million 820 MB