Browse Prior Art Database

Ethernet Device Driver Dual Type Field Filtering

IP.com Disclosure Number: IPCOM000108328D
Original Publication Date: 1992-May-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 1 page(s) / 55K

Publishing Venue

IBM

Related People

Morrison, WP: AUTHOR [+2]

Abstract

Disclosed is a program for performing Ethernet Local Area Network (LAN) "Type Field" filtering that concurrently conforms to both Standard Ethernet and IEEE 802.3, within the Ethernet Device Driver. 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, thus freeing 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 60% of the total text.

Ethernet Device Driver Dual Type Field Filtering

       Disclosed is a program for performing Ethernet Local Area
Network (LAN) "Type Field" filtering that concurrently conforms to
both Standard Ethernet and IEEE 802.3, within the Ethernet Device
Driver.  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, thus freeing 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 device
driver maintains a list of the type fields to look for.  One
additional parameter is passed with each type field given to the
device driver.  This additional parameter is the number of bytes
included in the type field match. With this information the device
driver can determine if the receive packet conforms to Standard
Ethernet or IEEE 802.3 standard and whether the packet is for this
node.

      When a receive packet arrives, the device driver tests the
packet to determine if the packet is a Standard Ethernet or an IEEE
802.3 packet.  To do this the driver extracts bytes 13 and 14 from
the packet. If the value of this two-byte entity is less than hex
0800, then the packet is an IEEE 802.3 packet; otherwise, the packet
will be a Standard Ethernet packet.  Now that the driver knows what
type of packet has arrived it extracts ...