Browse Prior Art Database

3172-2 Enhanced Data Flow Architecture for TCP/IP

IP.com Disclosure Number: IPCOM000109737D
Original Publication Date: 1992-Sep-01
Included in the Prior Art Database: 2005-Mar-24
Document File: 3 page(s) / 145K

Publishing Venue

IBM

Related People

Ratcliff, BH: AUTHOR [+2]

Abstract

Disclosed is a new line driver communication protocol which can be used to increase the throughput of the 3172 and other related products. Specifically, the new protocol defines a new method of communication between the PSCA (Parallel Serial Channel Adapter) Line Driver and the FDDI (Fiber Distributed Data Interface) Line Driver. This new protocol could be used for communication between any two line drivers where the Blocking and Deblocking of frames is required.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 49% of the total text.

3172-2 Enhanced Data Flow Architecture for TCP/IP

       Disclosed is a new line driver communication protocol
which can be used to increase the throughput of the 3172 and other
related products.  Specifically, the new protocol defines a new
method of communication between the PSCA (Parallel Serial Channel
Adapter) Line Driver and the FDDI (Fiber Distributed Data Interface)
Line Driver.  This new protocol could be used for communication
between any two line drivers where the Blocking and Deblocking of
frames is required.

      The new communications protocol describes the moving of the
Interconnect Control Program (ICP) Deblocker function to the specific
LAN adapter line driver and the moving of the ICP Blocker function to
the specific adapter microcode.  This eliminates the need for an
extra memory copy by the i486 processor and the passing of messages
between the line drivers for each individual frame contained in the
block of frames sent from the System/390* (S/390*) or System/370*
(S/370) host.

      The IBM 3172 Model 2 (3172-2) is a gateway providing
connectivity from IBM S/370 and S/390 mainframes to Local Area
Networks (LANs) and Wide Area Networks (WANs).  The first release of
the 3172-2 provides connectivity between IBM's PSCA (Parallel Serial
Channel Adapter) and the ANSI standard Fiber Distributed Data
Interface (FDDI).  The S/370 and S/390 host connects to the 3172 via
the Parallel Channel Interface to the PSCA adapter in the 3172.  Data
is passed between the Host and 3172 in blocks.  Each block contains a
group of FDDI frames.  The frames are separated by a four-byte header
which is used to determine the length of the current frame.  The new
communication protocol defined in this disclosure was implemented in
this environment.  The Blocker and Deblocker tasks mentioned below
are part of the ICP V2.1 program which runs on the 3172-2.

      In the original architecture, when a Block of frames is sent
from an S/370 or S/390 Host, the Deblocker receives a message from
the PSCA Line Driver when the data has been received in the PSCA
adapter memory.  The message informs the Deblocker of the location in
PSCA memory of the "block" of frames and the total size of the block.
The Deblocker task then copies each individual frame in the block
from the PSCA memory to System memory.  Once the frames have all been
copied, a message for each frame is sent to the FDDI Line Driver.
The message informs the FDDI Line Driver of the location and size of
each frame in System memory.  The FDDI Line Driver then informs the
FDDI microcode of the location of each frame in System memory.

      The new communication protocol moves the Deblocker function to
the FDDI Line Driver.  The Deblocker task just serves as a router to
the various LAN line drivers in the 3172.  When the Deblocker task
receives the message from the PSCA Line Driver pointing to a block of
frames, the message is just routed to the FDDI Line Driver. ...