Browse Prior Art Database

Token-Ring 16/4 Adapter with Full-Duplex Switching Operation Mode

IP.com Disclosure Number: IPCOM000112040D
Original Publication Date: 1994-Apr-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 2 page(s) / 69K

Publishing Venue

IBM

Related People

Christensen, KJ: AUTHOR [+4]

Abstract

The concept of allowing an existing token-ring adapter to be used in a new full-duplex mode for point-to-point connections is disclosed. When in full-duplex mode, all token protocols are suspended within the adapter, thus permitting packets to be immediately transmitted on the output link. Adapters operating in this mode can simultaneously receive and transmit packets. Packet bridging/routing and delivery are performed by an interconnect switch device.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Token-Ring 16/4 Adapter with Full-Duplex Switching Operation Mode

      The concept of allowing an existing token-ring adapter to be
used in a new full-duplex mode for point-to-point connections is
disclosed.  When in full-duplex mode, all token protocols are
suspended within the adapter, thus permitting packets to be
immediately transmitted on the output link.  Adapters operating in
this mode can simultaneously receive and transmit packets.  Packet
bridging/routing and delivery are performed by an interconnect switch
device.

      The token-ring Media Access Control (MAC) protocol is primarily
executed in adapter microcode with significant hardware assist.  The
Figure shows a token-ring adapter that is programmable to operate in
full-duplex transmit and receive operation via microcode control.
The token-ring adapter can be programmed to operate in either the
normal token mode or in the full-duplex mode by suspending the ring
task microcode that is executed within the token-ring protocol
processor that is on the token-ring MAC chip.  The suspended
token-protocol functions include:

o   Token-access (i.e., wait for token) protocol

o   Passive and active token monitor functions

o   Frame stripping operation

o   Frame repeating and end frame status update

      Received frames can still be checked for frame check sequence
errors, and reports sent to a management entity if error thresholds
are exceeded.  This will allow a remote manager node to monitor for
link errors as done today.

      A key aspect of the full-duplex concept is that the token-ring
frame format is...