Endace Measurement Systems Limited
http://www.endace.com
EDM01.05-12r1 DAG 3.7T Card User Manual
Copyright, all rights reserved.
35
Version 6. 22 September 2005.
6.0 DATA FORMATS OVERVIEW
In this chapter
This chapter covers the following sections of information.
•
Data Formats
•
Timestamps
6.1 Data Formats
Description
The DAG card uses the ERF Type 5 Multi-channel HDLC Frame Record,
ERF Type 6 Multi-Channel Raw Link Data Record, and ERF Type 7
Multi-channel ATM Cell Record. Timestamps are in little-endian
[Pentium native] byte order.
All other fields are in big-endian [network] byte order.
All payload data is captured as a byte stream, no byte re-ordering is
applied.
In this section
This section covers the following topics of information.
•
Generic Variable Length Record
•
Type 5 Multi-channel HDLC Frame Record
•
Type 6 Multi-channel RAW Link Data Record
•
Type 7 Multi-channel ATM Cell Record
6.1.1 Generic Variable Length Record
Description
Endace DAG Network Measurement Interface Cards [NMICs] produce
trace files in their own native format, the Extensible Record Format
[ERF].
The ERF format consists of a series of records. Each record describes one
packet. An ERF format file consists only of ERF records; there is no
special file header. This allows file concatenation and splitting to be
performed arbitrarily on ERF record boundaries.
Table
Table 6-1 shows the generic variable length record.
timestamp
timestamp
type flags
rlen
Lctr wlen
(rlen - 16) bytes of record
Table 6-1. Generic Variable Length Record.
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