Endace DAG 5.2X, User Manual

Page: 29 / 66

EDM01-33v1 DAG_7.5G4_Card_User_Guide
©2008 Endace Technology Ltd. Confidential - Version 1 - November 2008 25
slen
Before you begin to capture data you can set the size that you want the captured packets to
be. You can do this using the
dagconfig
tool to define the packet snaplength (
slen
).
Note: The snaplength value must be a multiple of 8 and in the range 48 to 9600 per card
inclusive.
By default,
slen
which is the portion of the packet that you want to capture is set to 48 per
card. This means that only the first 48 bytes of each packet will be captured.
If for example you want to capture only the IP header of each packet you may want to set the
length to a different value. Alternatively if you want to ensure you capture the whole packet
you can set the length to a larger value.
Example
Setting up a DAG 7.5G4 card with a snap length of 200 bytes:
dagconfig -d0 slen=200
Note:
The ERF header is not included in the
slen
value. Therefore a
slen
of 48 will
produce a 64-byte capture record made up of 48 bytes plus the number of bytes in
the ERF header.
steer
The algorithm to use to steer the incoming packet.
Option Description
stream0
All traffic sent to stream 0 (3.8 balance f/w only)
parity
Load balance traffic by parity (3.8 balance f/w only)
crc
Load balance traffic by crc (3.8 balance f/w only)
iface
Port A to stream 0, Port B to stream 2 (3.8 balance f/w only)
colour/dsm
Load balance traffic by colour/dsm. Colour is applicable to IPF traffic.
terf_strip16/terf_strip32/noterf_strip
Strips the CRC value (16 or 32 bits) from the packet or sends packet “as is” (
noterf_strip
).
The TERF line in the current configuration indicates the current Terf option.
Note:
Only displayed if the DAG card supports transmit (i.e. has a terf image).
Example
dagconfig terf_strip16
dagconfig terf_strip32
dagconfig noterf_strip
time_mode
Sets the time release mode.
nodelay
sends packets out with no delay. Shows as
no_time_mode
.
relative
mode sends out packets in the same time spacing as they where
received. Applicable to TR-TERF.
Example
dagconfig nodelay
dagconfig relative