Endace DAG 3.8S, User Manual

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EDM01-09v7 DAG 3.8S Card User Guide
©2005 27 Version 9: May 2006
Chapter 5 Running Data Capture Software
Introduction
For a typical measurement session, the
scripts/dag38start
script is
edited and used to operate the cards directly.
In this chapter This chapter covers the following sections of information.
•
Starting DAG 3.8S Card Capture Session
•
High Load Performance
•
DAG 3.8S Card Packet Transmission Capabilities
5.1 Starting DAG 3.8S Card Capture Session
Description
The various tools used for data capture are in the
tools
sub-directory.
For a typical measurement session, ensure the driver is loaded, the
firmware has been downloaded, and the card is configured.
The integrity of the DAG 3.8S card’s physical layer is then set and
checked.
Process
Starting a data capture session is described in the following process.
Process Description
Slen parameter default
setting.
Parameters are set with
dagthree
.
Slen parameter is set by default to 48.
If only part of a packet is required, such as for IP header
capture, the value of
slen
can be changed using
dagthree
.
dagthree slen=128 varlen
Setting capture
session parameters.
The card can operate in two modes, variable length capture
(
varlen
), and fixed length capture (
novarlen
).
In variable length capture mode, a maximum capture size is
set with
slen=N
bytes. This figure should be in the range 16
to 2040 and is rounded down to the nearest multiple of 4.
Packets longer than slen are truncated. Packets shorter than
slen will produce shorter records, saving bandwidth and
storage space. For example, full packet capture:
dagthree –d dag0 varlen slen=2040