Browse Prior Art Database

Multiple Independent Channels for LAN Adapters

IP.com Disclosure Number: IPCOM000117447D
Original Publication Date: 1996-Feb-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 60K

Publishing Venue

IBM

Related People

Walker, AD: AUTHOR [+2]

Abstract

Currently, LAN adapters receive all frames through a single logical interface and software must demultiplex the frames to the proper destination in the system. The destination could be the disk drive subsystem, video subsystem or audio subsystem for example. This process of software demultiplxing requires considerable overhead in the device driver and adds latency to real-time frames that may not be tolerated. Disclosed are several methods for performing this demultiplexing in hardware or microcode on the LAN adapter, thus freeing the system and increasing throughput while reducing latency.

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Multiple Independent Channels for LAN Adapters

      Currently, LAN adapters receive all frames through a single
logical interface and software must demultiplex the frames to the
proper destination in the system.  The destination could be the disk
drive subsystem, video subsystem or audio subsystem for example.
This process of software demultiplxing requires considerable overhead
in the device driver and adds latency to real-time frames that may
not be tolerated.  Disclosed are several methods for performing this
demultiplexing in hardware or microcode on the LAN adapter, thus
freeing the system and increasing throughput while reducing latency.

      The main point of this invention is providing the ability to
have hardware route frames rather than software.  There are several
parameters in a LAN frame that can be used to discriminate where
traffic should flow once on-board the LAN adapter.

      The destination MAC address is the first field that can be
used to route frames.  Multimedia broadcasts, such as CNN, on the LAN
could be destined to a particular group address.  Anyone wishing to
view that broadcast, would set the associated group address and the
hardware would forward the video stream directly to the video
playback subsystem.  Optionally, the MAC header and trailer could be
removed by the LAN adapter since these fields are not needed by the
video sub-system. This would further increase overall system
performance.

      For token-ring networks, the Frame Priority bits in the
Frame Control field could be used to distinguish vi...