Endace DAG 4.5G2 Card, User Manual

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EDM 01-17 DAG 4.5G2/G4/GF Card User Guide
Generic
Header
(cont.)
The fields are described below:
timestamp
The time of arrival of the cell, an ERF 64-bit timestamp. See
Timestamps in Chapter 5: Synchronizing Clock Time earlier in
this User Guide for more information.
type
One of the following:
2: TYPE_ETH
16: TYPE_DSM_COLOR_ETH
flags
This byte is divided into several fields as follows:
1-0: Enumerates capture interface 0-3
2: Varying record lengths
3: Truncated record (insufficient buffer space)
4: RX error (link layer error)
5: DS error (internal error)
6: Reserved
7: Reserved.
Record length. Total length of the record transferred over the
PCI bus to storage.
rlen
Depending upon the ERF type this 16 bit field is either a loss
counter of color field. The loss counter records the number of
packets lost between the DAG card and the memory hole due
to overloading on the PCI bus.
lctr
wlen
Wire length. Packet length including some protocol overhead.
The exact interpretation of this quantity depends on physical
medium.
Note: The Ethernet frame begins immediately after the pad byte so that
the layer 3 (IP) header is 32-bit aligned.
Type-2 Record The TYPE_ETH variable length record is shown below:
Byte 3 Byte 2 Byte 1 Byte 0
timestamp
timestamp
type 2 flags rlen
lctr wlen
offset pad
(rlen - 18) bytes of record
©2005-2006 34 Version 4: August 2006