StorageTek Host Software Component 6 User Manual

1st ed., 6/30/04 - 312579601

HSC communication functions ensure that passing of pertinent information between HSC 
components and hosts is accomplished successfully. 

The HSC permits you to select the hierarchy of methods used for host-to-host 
communications. The communications services are designed to provide you with fail-safe 
communications between HSC hosts in a data center complex. 

The following kind of information is passed between hosts: 

• control data set switch information 
• CAP status information. 

Communications services that are available fall into three categories: 

• Telecommunications access method through the ACF/VTAM network – This method 

of host-to-host communications provides the highest performance and reliability. 

• Communication through the LMU – This method of host-to-host communications is 

a lower performance method than ACF/VTAM. 

• Communication through the CDS – This method of host-to-host communications is a 

lower performance method than either ACF/VTAM or LMU. 

Figure 8 illustrates the available communication methods and relative hierarchy of the 
methods.

 

HOST 1

LMU

VTAM

COMMUNICATION

METHOD

HOST n

CDS

HOST 0

HOST 2

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