EDM01-36v10 DAG_9.2X2_Card_User_Guide - Data formats
©2010 - 2012 Endace Technology Ltd. Confidential - Version 10 - May 2012
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Extension Headers (EH)
Introduction
The addition of an Extension Header into the ERF record allows extra data relating to the packet to be
transported to the host. The extension header allows certain features to be added independently of ERF
types, for example, features shared by different ERF records do not have to be implemented separately.
This results in automatic support across ERF types.
Bit 7 of the ERF type field is used to indicate that Extension Headers are present. If set to '1' Extension
Headers are present. The Extension Header type field indicates the type and format of the Extension
Header. It also indicates whether further Extension Headers are present. If bit 7 of the Extension Header
is set to '1' further Extension Headers exist in the record. The Extension Headers are 8 bytes in length.
The following diagram shows presence of an Extension Header in addition to the ERF record.
The following diagram shows presence of two Extension Headers with Bit 7 of the first Extension Header
set to '1'.
