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Browse Prior Art Database

Ethernet Adapter Single and Dual Type Field Filtering

IP.com Disclosure Number: IPCOM000108260D
Original Publication Date: 1992-May-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 1 page(s) / 54K

Publishing Venue

IBM

Related People

Morrison, WP: AUTHOR [+2]

Abstract

Disclosed is a device interface for performing Ethernet Local Area Network (LAN) "Type Field" filtering that concurrently conforms to both Standard Ethernet and IEEE 802.3, within the adapter card. This filtering performs the function of allowing only those Ethernet packets that are for this node to be sent to the higher layers of software. This frees the main system processor from handling all the packets in the higher layers of software when only a fraction of those packets are required for this node.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 62% of the total text.

Ethernet Adapter Single and Dual Type Field Filtering

       Disclosed is a device interface for performing Ethernet
Local Area Network (LAN) "Type  Field" filtering that concurrently
conforms to both Standard Ethernet and IEEE 802.3, within the adapter
card.  This filtering performs the function of allowing only those
Ethernet packets that are for this node to be sent to the higher
layers of software. This frees the main system processor from
handling all the packets in the higher layers of software when only a
fraction of those packets are required for this node.

      To implement both standards of type field matching, the adapter
card is given a list of the type fields to look for. Two additional
parameters are passed along with each type field given to the adapter
card.  These additional parameters are 1) an offset in the packet
where type field matching is to be performed and 2) the number of
bytes in- cluded in the type field match,  either one or two bytes.
With these additional parameters, the adapter card can determine
which packets are for this node and which packets are to be
discarded.  When a receive packet arrives, the adapter card looks in
the specified location(s) in the packet and compares this field with
those from the list.  If a match is found, the packet is forwarded to
the next higher layer of software. If no match is found, the packet
is discarded within the adapter card.

      In the event that the adapter card is not given a li...