Endace DAG 7.1S, User Manual

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EDM 01-17 DAG 7.1S Card User Guide
Configuring for Transmission.
To configure the DAG card for transmission, you must allocate some
memory to a transmit stream.
In the
dagconfig
output,
buf=nMB
indicates that n mebibytes of memory
has been allocated to the DAG card in total. You can split this allocation
between the receive and transmit stream buffers which is displayed as a
ratio as
mem=X:Y
, where X is the memory allocated in MB to the rx stream
“0” and Y is the memory allocated to tx stream “1” in MB.
By default, memory is evenly split between the rx streams, with the
transmit streams having no memory allocated.
If you wish to use the card for both transmitting and receiving, youshould
use the
rxtx
option. This allocates 16MiB of memory to each transmit
stream, and divides the remaining memory between the receive streams.
Alternatively you can set the memory allocation directly using the mem=
X:Y option.
Note: You can only change the stream memory allocations when no
packet capture or transmission is in progress.
Explicit Packet Transmission
The DAG card will not respond to ARP, ping, or router discovery
protocols. It will only transmit packets explicitly provided by the user.
This capability allows you to use the DAG card as a simple traffic load
generator. It can also be used to retransmit previously recorded packet
traces.
The packet trace is transmitted at 100% line rate. The packet timing of the
original trace file is not reproduced.
Dagflood Tool
The
dagflood
tool can transmit ERF format packet traces. The ERF trace
file to be transmitted must contain only ERF records of the type matching
the current link configuration.
The length of the ERF records to be transmitted must be a multiple of 64-
bits. When capturing a packet trace for later transmission, you can set 64-
bit alignment using the
dagconfig align64
command.
Convert Trace Files
It is also possible to convert trace files that have been captured without the
align64
option. You can do this using:
dagconvert -v -i in.erf -o out.erf -A8
If you are unsure if a trace file is 64-bit aligned you can test the file using
the
dagbits
tool
dagbits -vvc align64 -f tracefile.erf
If a captured trace file is not available, the
daggen
program is capable of
generating trace files containing simple traffic patterns. This allows the
DAG card to be used as a test traffic generator.
©2006 29 Version 2: May 2006