Chapter 2: Concepts and Procedures

Connection refused

If the Adaptive Server max network packet size configuration parameter is set to 512 (the default), clients connections to OpenSwitch fail and the client receives this error message:

The packet size (2048) specified at login time is illegal. Legal values are between 512 and 512.

To correct this problem you can reconfigure the Adaptive Server max network packet size to be 2048, or you can reconfigure the OpenSwitch MAX_PACKETSIZE to be 512.

Reconfiguring Adaptive Servermax network packet size to be 2048

Set the SYBASE environment variable. In a Command Prompt window, go to %SYBASE% on Windows and $SYBASE on UNIX and enter:

SYBASE.bat (Windows)

or

SYBASE.csh (UNIX)
Use isql to log in to the Adaptive Server as an administrator:
```
isql -Usa -P -S <Adaptive_Server_server_name>
```

Execute:

sp_configure 'max network packet size', 2048
go

Restart the Adaptive Server.
Restart OpenSwitch to establish the client connection.

Reconfiguring OpenSwitch MAX_PACKETSIZE to be 512

Remember that MAX_PACKETSIZE refers to the maximum size of the TDS packet. This option is used to tune the data throughput across the network and can significantly improve performance when larger packet sizes are used.

Shut down the OpenSwitch server:
1. Set the SYBASE environment variable. In a Command Prompt window, go to %SYBASE% on Windows and $SYBASE on UNIX and enter:
  
  SYBASE.bat (Windows)
  
  or
  
  SYBASE.csh (UNIX)
2. Use isql to log in to OpenSwitch as an administrator:
```
isql -U<ADMIN_USERNAME> 
     -P<ADMIN_PASSWORD> 
     -S <OpenSwitch_server_name>
```
3. Execute:
```
rp_shutdown
go
```
Use a text editor to modify the OpenSwitch configuration file (<OpenSwitch_server>.cfg), which is located in %OPENSWITCH%\config on Windows and in $OPENSWITCH/config on UNIX.

Change the MAX_PACKETSIZE value from 2048 (the default) to 512. For example:
```
MAX_PACKETSIZE=512
```
Restart the OpenSwitch server.

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