Browse Prior Art Database

Multi-hop SNA Sessions Using LU6.2

IP.com Disclosure Number: IPCOM000122405D
Original Publication Date: 1991-Dec-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 101K

Publishing Venue

IBM

Related People

Brodd, JL: AUTHOR [+6]

Abstract

In order to take advantage of the LEN boundary function support provided by NCP and VTAM, and also to take advantage of the multi-hop capability provided by APPN, multi-hop communications between an AS/400* and a Remote Workstation controller and its associated 5250 dependent workstation (DWS) devices has been accomplished by encapsulating the SNA LU Type 4, SNA LU Type 7 and 5250 datastream in SNA LU Type 6.2 (LU6.2) sessions.

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Multi-hop SNA Sessions Using LU6.2

      In order to take advantage of the LEN boundary function
support provided by NCP and VTAM, and also to take advantage of the
multi-hop capability provided by APPN, multi-hop communications
between an AS/400* and a Remote Workstation controller and its
associated 5250 dependent workstation (DWS) devices has been
accomplished by encapsulating the SNA LU Type 4, SNA LU Type 7 and
5250 datastream in SNA LU Type 6.2 (LU6.2) sessions.

      In order to take advantage of the LEN boundary function support
provided by NCP and VTAM, and also to take advantage of the multi-hop
capability provided by APPN, multi-hop communications between an
AS/400 and a Remote Workstation controller and its associated 5250
dependent workstation (DWS) devices must be accomplished through the
use of SNA LU Type 6.2 (LU6.2) sessions.

      In order to implement the least disruptive and most efficient
method of providing this support, we have provided the following new
functions:
1.  Encapsulation of the SNA LU Type 4 and SNA LU Type 7 (LU4/7)
datastreams within an LU6.2 session
     This new function provides for the encapsulation of both SSCP-LU
flows as well as normal LU4/7 session flows, so that a completely
transparent multi-hop capability is achieved.
     5250 DWS devices require the SNA datastream in the form of Path
Information Units (PIUs) so that they can function as they do prior
to our support.  This support provides the function to encapsulate
LU4/7 PIUs between the AS/400 and the remote workstation controller.
     We have reserved a unique LU6.2 General Data Stream Identifier
(GDS ID) indicating that the data that follows the GDS ID is
encapsulated LU4/7 session data.  This GDS ID is 'D824'X.

      We have employed the use of the LU6.2 continued logical record
indicator to identify when the receiver of the LU6.2 data should pass
received data to the application program.  The continued logical
record indicator is used to allow a chain of LU4/7 data to be passed
up to the application program.  In our design, the AS/400 system
requires full chains of LU4/7 data, so the continued logical record
indicator is used whenever multiple logical records contain a single
chain of LU4/7 data.
2.  Use of the signal-request-to-send verb of LU6.2 in order to solve
LU4/7 specific change of direction requirements.
     Since more than one LU 4/7 flow is being encapsulated on the LU
6.2...