Multiple APPN-capable Connections to Same AS/400 Not Supported

• Microsoft SNA Server for Windows NT, versions 2.0, 2.1, 2.11, and 2.11 SP1

SUMMARY

While SNA Server does support one or more connections to the same host system (see Q107192), the AS/400 does not support more than one concurrent APPN-capable connection from a single SNA Server 2.x system (acting as a LEN node), over any link type (802.2 Token Ring, Ethernet, SDLC, or X.25).

SNA Server 3.0 does support multiple APPN-capable connections to the same AS/400.

For additional information on how SNA Server 3.0 supports multiple APPN-capable connections to an AS/400, please see the following article in the Microsoft Knowledge Base:

   ARTICLE-ID: Q162133
   TITLE: SNA Server 3.0 Supports Multiple Connections To Same AS/400

   ARTICLE-ID: Q145714
   TITLE     : How to Establish Two 802.2 Connections To AS/400

For additional information, please see the following article in the Microsoft Knowledge Base:

   ARTICLE-ID: Q126395
   TITLE     : Ways to Increase the Number of AS/400 LU6.2 Sessions

MORE INFORMATION

For SNA Server to connect to an AS/400, an APPC controller definition must exist for SNA Server's local control point name. The APPC controller may be autocreated by the AS/400 or manually created by the AS/400 administrator.

The AS/400 allows only a single APPC controller, with a given control point name, over any line it supports. If two connections are defined in SNA Server to the same AS/400 (for example, two 802.2 connections, or one 802.2 and one SDLC, etc.), the AS/400 rejects the second connection request unless the first APPC controller definition is deleted.

SNA Server 2.x can only be configured with one local control point name (configured in SNA Admin from the Session Properties dialog box).

For 802.2 connections, the AS/400 allows only a single APPC controller to have a specific network adapter address. So, if an SNA Server connects to an AS/400 with one local control point name configured (over an 802.2 connection), and the local control point name is later changed, the AS/400 will refuse the connection attempt with the new name because an APPC controller definition already exists with the same network adapter address.