BASEstartm Classic DAS
for Siemens H1tm Protocol
Installation and User's Guide
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2.3.2 Configuring DECnet Plus Parameters

Use SYS$STARTUP:NET$CONFIGURE to configure your OSI Transport Template for Siemens communications.

Note
Be sure to configure the template as a NULL Internet transport template.

Table 2-4 gives a list of recommended OSI transport template parameters. Table 2-5 gives a list of OSI transport parameters that may need to be modified for your intallation. These parameters are explained in detail in the DECnet Plus documentation. Some are inter-dependent so that modifying one parameter may require changing other ones also.

Table 2-4 OSI Transport Template Parameters
Parameter Recommended Value1
Keepalive Time 3 2
Retransmit Threshold 2 2
CR Timeout 5
ER Timeout 5

1The values of these parameters depends on your specific network configuration and expected response times.
2The product of these values must be lower than the /TIMEOUT value on the device definition.

Table 2-5 OSI Transport Parameters
Parameter
Maximum Transport Connections
Maximum Remote NSAPs

Other timers in the transport template may need to be modified depending on your specific hardware and network configuration.

To modify transport template values place an NCL script in SYS$COMMON:[SYSMGR] and execute it from your system startup command file. Use the following syntax to execute an NCL script. 


$RUN SYS$SYSTEM:NCL 
@SYS$MANAGER:CUSTOM_NCL_SCRIPT.NCL

Example 2-1 shows an example OSI transport template configured for NULL Internet.

Example 2-1 NULL Internet OSI Transport Template 

NCL>sho osi transport template h1net all 
 
Node 0 OSI Transport Template h1net 
at 1996-10-17-14:49:41.446-04:00Iinf 
 
Identifiers 
 
    Name                              = h1net 
 
Characteristics 
 
    Keepalive Time                    = 60 
    Retransmit Threshold              = 8 
    Initial Retransmit Time           = 5 
    CR Timeout                        = 30 
    ER Timeout                        = 30 
    Network Service                   = CLNS 
    Security                          = <Default value> 
    Classes                           = 
       { 
          4 
       } 
    Checksums                         = True 
    Maximum NSDU Size                 = 2048 
    Expedited Data                    = True 
    CONS Template                     = <Default value> 
    Use CLNS Error Reports            = True 
    Acknowledgement Delay Time        = 1 
    Local NSAP                        = <Default value> 
    CLNS Inactive Area Address        = 
       { 
          49::FF-00 
       } 
    Inbound                           = True 
    Loopback                          = False 
    Send Implementation Id            = True 
    Extended Format                   = True 
    Network Priority                  = 0 
    Send Preferred maximum TPDU size  = True 
    Send Request Acknowledgement      = True 
    RFC1006 Port Number               = 102

Example 2-2 shows an example OSI transport definition.

Example 2-2 OSI Transport 

NCL>sho osi transport all char 
 
Node 0 OSI Transport 
at 1996-10-17-14:57:47.388-04:00Iinf 
 
Characteristics 
 
    Maximum Transport Connections     = 200 
    Maximum Receive Buffers           = 4000 
    Delay Weight                      = 5 
    Delay Factor                      = 4 
    Maximum Window                    = 20 
    Maximum Multiplexing              = 4294967295 
    Disconnect Holdback               = 0 
    Maximum Network Connections       = 4294967295 
    ISO Version                       = 1 
    Version                           = V1.1.0 
    CONS Classes Supported            = 
       { 
          0 , 
          2 , 
          4 
       } 
    CLNS Classes Supported            = 
       { 
          4 
       } 
    Support MAP                       = False 
    Maximum Remote NSAPs              = 201 
    NSAP Selector                     = 33 
    CONS Filters                      = 
       { 
          "OSI Transport" 
       } 
    Congestion Avoidance              = False 
    CONS NSAP Addresses               = 
       { 
       } 
    Maximum RFC1006 Connections       = 4294967295 
    RFC1006 Listener Ports            = 
       { 
           102 
       } 
    Out Of Order Cache Size           = 10

Furthermore there is a similar set of parameters pre-defined for the Siemens CP-535 communications card. The parameters on the host must match the pre-defined parameters on the Siemens CP-535. Setting the parameters at the recommended values will allow normal communications with the Siemens programmable controller. It is possible to choose other values for these parameters depending on your special network requirements. However, please consult DECnet Plus documentation carefully before changing any of these parameters.

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