Endace Measurement Systems Limited
http://www.endace.com
EDM01.05-04r1 DAG 3.6GE User Manual
Copyright, all rights reserved.
16
Revision 7. 22 September 2005.
4.1 Starting Capture Session
, continued
Process
,continued
Process Description
Setting fixed length
mode.
In fixed length mode, packets longer than the
selected slen are truncated to slen, but packets
shorter than slen will produce records that are
padded out to the slen length.
Large values of slen in fixed length mode, as
short packets arriving will produce large padded
records, wasting bandwidth and storage space.
For fixed length 64-byte records for example,
choose
slen=44
(64 – ERF header size of 16 –
alignment padding 4):
dagthree –d dag0 novarlen slen=44
Setting packet capture
settings.
Capture settings must be set for each card in
use. A capture session is started on a card,
using dagsnap.
dagsnap –v –o tracefile
The option
-v
is used to provide user
information during capture; it can be omitted for
automated trace runs.
If the
tracefile
parameter is not specified the
tool will write to stdout, which can be used to
pipeline
dagsnap
with other tools from the
dagtools
package.
Stopping dagsnap
running.
By default
dagsnap
will run forever.
dagsnap
can be stopped with a signal:
killall dagsnap
dagsnap
can also be configured to run for a
fixed number of seconds and then exit with the
–s
option
.
