Endace DAG 3.6D, Руководство пользователя

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EDM01-14 DAG 3.6D Card User Guide
©2005 31 Version 10: May 2006
6.1 Data Formats
, continued
Data Format Description
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.
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.
Figure Figure 6-2 shows the Type 1 PoS HDLC Variable Length Record. The
diagram is not to scale.
timestamp
timestamp
type:1 flags rlen
lctr wlen
HDLC Header
(rlen - 20) bytes of packet
Type 1 PoS HDLC Variable Length Record.
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