NOVELL TECHNICAL INFORMATION DOCUMENT

TITLE:              CSLIST Randomization
DOCUMENT ID:        TID250185
DOCUMENT REVISION:  A
DATE:               16JUN94
ALERT STATUS:       Yellow
INFORMATION TYPE:   Symptom Solution
README FOR:         SAA005.EXE

NOVELL PRODUCT and VERSION:
NetWare for SAA 1.3B

ABSTRACT:

NW4SAA 1.3B "patch" useful for some organizations but unwise for many. 
Provides algorithm which randomly assigns new connections among your SAA comm
servers so that one will not become congested. 1) If you access several SAA
servers at a central site, consider using SAA005. 2) If your SAA servers are
at multiple sites, connected by a WAN, SAA005 probably will not be a good
choice. 3) If you have only one SAA server, SAA005 is pointless.

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SYMPTOM

Long response time or time-outs trying to connect.

CAUSE

All connections are being made to one of several NetWare for SAA servers.

SOLUTION

Install SAA005.

Self-Extracting File Name:   SAA005.EXE

Files Included     Size     Date

SAA005.TXT      ( This File )
CMSPX.NLM41764 2-17-94

Installation Instructions:

Copy CMSPX.NLM to SYS:SYSTEM on the NetWare for SAA servers.

Patch History:

This ia a special purpose "patch."  No version of this patch has ever been
placed in the NetWire Library.

Solution Specifics:

The way an emulation program finds a SAA server and gets a 3270 session is as
follows.

1. The emulation program does a "NEAREST SERVER QUERY" with server type130 for
a communications executive server. ( commserver )

2. The emulation program attaches to the commserver that answered first.

3. The emulation program requests a CSLIST from the commserver attached to in
step 2.

4. The emulation program then attaches to the first commserver in that CSLIST
and will attempt to get a 3270 session from this commserver if a session is
available.  If none is available it will attach to the nextcommserver in the
CSLIST and try again and so on down the list of commservers till it finds an
available session.

The CSLIST that gets presented to the client is built by the commserver from
the bindery.  Till now the order of the commservers in the CSLIST was the same
order the commservers were loaded and put into the bindery list.  SAA005
randomizes the order of the commservers in the CSLIST.

The need for SAA005 would be most apparent when the commservers are centrally
located at one site and users are all set to find any available session on any
available comm exec server.  This is done by using the wildcard symbol (
usually " * "  ) as the commserver name in the emulation configuration.

What would typically happen when this was used without randomizing is that
everyone needing a 3270 session would go to the first commserver in the
CSLIST.  This would cause utilization of this server during peak login times
to be excessive, which would result in long response times or time-outs trying
to connect.  This randomizer patch will distribute this load across all the
commservers.

Not all environments will want to randomize the CSLIST.  When commservers are
separated by WANs this patch can become detrimental when using 3270 emulation
to SAA.  In this WAN scenario what would result would be some of the 3270
sessions would be from the commserver located across the slower WAN connection
even if faster local sessions were available.  This could result in some users
that received their 3270 session from a remote commserver having slow response
times or timeouts that could drop the 3270 session.

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