Endace Measurement Systems Limited
http://www.endace.com
EDM01.05-12r1 DAG 3.7T Card User Manual
Copyright, all rights reserved.
36
Version 6. 22 September 2005.
6.1.1 Generic Variable Length Record
, continued
Data format
An overview of the data format used is described in the following table.
Data Format
Description
type:
This field contains an enumeration of the frame
subtype. If the type is zero, then this is a legacy
format.
0: TYPE_LEGACY
1: TYPE_HDLC_POS: PoS w/HDLC framing
2: TYPE_ETH: Ethernet
3: TYPE_ATM: ATM Cell
4: TYPE_AAL5: reassembled AAL5 frame
5: TYPE_MC_HDLC: Multi-channel HDLC frame
6: TYPE_MC_RAW: Multi-channel Raw link data
7: TYPE_MC_ATM: Multi-channel ATM Cell
flags:
This byte is divided into 2 parts, the interface
identifier, and the capture offset.
1-0: capture interface 0-3
2: varying record lengths present
3: truncated record [insufficient buffer space]
4: rx error [link error]
5: 5: ds error [internal error]
7-6: 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.
Wlen:
wire length
Packet length including some protocol overhead.
The exact interpretation of this quantity depends on
physical medium.
