EDM01-02: DAG 4.2S Card User Guide
©2005
33
Version 7: May 2006
Data format overview
, continued
Data Format
Description
flags
This byte is divided into 2 parts, the interface
identifier, and a set of 1-bit flags.
1-0:
Capture interface 0-3.
2:
Varying record lengths present.
3:
Truncated record [insufficient buffer
space].
4:
rx error [link error].
5:
ds error [internal error].
6-7:
Reserved.
rlen:
record length
Total length of the record transferred over PCI
bus to storage.
lctr:
loss counter
A 16 bit counter, recording the number of packets
lost since the previous record.
Records can be lost between the DAG card and
memory hole due to overloading on PCI bus. The
counter starts at zero, and sticks at
0xffff.
NOTE: This is not present in Type 10 and Type
11 ERF records.
wlen:
wire length
Packet length including some protocol overhead.
The exact interpretation of this quantity depends
on the physical medium.
offset
Number of bytes not captured from start of frame.
Typically used to skip link layer headers when not
required in order to save bandwidth and space.
This field is currently not implemented, contents
can be disregarded.
