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Browse Prior Art Database

High-Speed Serial Interface Micro Channel Adapter

IP.com Disclosure Number: IPCOM000122461D
Original Publication Date: 1991-Dec-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 3 page(s) / 149K

Publishing Venue

IBM

Related People

Beressi, HD: AUTHOR [+8]

Abstract

By adapting a general purpose high-speed serial interface to the MICRO CHANNEL*, a very versatile communications device has been realized. The high-speed serial interface, in conjunction with an external data staging or multiplexing device, provides access to a wide variety of high-speed point-to-point networking services. The MICRO CHANNEL bus provides the necessary backbone to efficiently route data packets transferred over the high-speed serial interface to different local area networks (LANs), wide area networks (WANs) or channels.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 48% of the total text.

High-Speed Serial Interface Micro Channel Adapter

      By adapting a general purpose high-speed serial interface
to the MICRO CHANNEL*, a very versatile communications device has
been realized.  The high-speed serial interface, in conjunction with
an external data staging or multiplexing device, provides access to a
wide variety of high-speed point-to-point networking services.  The
MICRO CHANNEL bus provides the necessary backbone to efficiently
route data packets transferred over the high-speed serial interface
to different local area networks (LANs), wide area networks (WANs) or
channels.

      The High Speed Serial Interface (HSSI) used on this adapter is
a pseudo standard which was jointly developed by Mitri Halabi of
T3plus Networking, Inc. and John T. Chapman of Cicso Systems, Inc.
Both companies currently market networking equipment which uses this
interface.  HSSI supports a full duplex serial link.  The transmit
and receive clocks are supplied by the Data Communications Equipment
(DCE), and they may be gapped.  ECL electrical interface levels allow
for serial data rates up to 52 Mb/s.

      The top of the figure illustrates where various networking
functions would be performed in a typical application.  The Data
Terminal Equipment (DTE) in this example would be the HSSI MICRO
CHANNEL adapter.  At the networking or routing layer, the DTE would
receive data packets from an end-point device, such as a host
computer, or other networks, such as Ethernet or Fiber Distributed
Data Interface (FDDI).

      Communications with different networks is possible at this
level because of protocol standards, such as TCP/IP, SNA, etc.  Based
on information in the IP header and tables kept in the DTE local
storage, the DTE determines and maintains routes for the data
packets, and may also fragment and assemble packets.  At the Data
Link Control (DLC) layer, two types of services may be provided.
Type I service offers a connectionless best effort datagram service.
For this type of service the DLC performs some basic functions such
as constructing headers, and generating/verifying packet checksums.
Type II service offers a connection-oriented, reliable, in-sequence
delivery service. In addition to functions performed for Type I
service, the DLC will acknowledge packets, retransmit packets, and
manage windows.  At the Physical layer, the DTE transfers data over
the HSSI interface to the DCE.

      The DCE must take the data received over the HSSI interface and
prepare it for transmission over the high-speed communications link
shown in the figure.  Due to differences in the two interfaces, the
DTE must perform a number of functions such as:  translation to a
different mechanical and electrical interface; adding and deleting
bits for data rate conversion; data framing; and data multiplexing if
the high-speed link is shared among multiple devices.

      After the data is processed by the DCE, it is sent out along
...