Understanding SQL*Net

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Creating the TNSNAV.ORA File for Clients and Servers

If you do not have an Interchange in your network, you do not need to use the TNSNAV.ORA file, although Network Manager generates one automatically.

LOCAL_COMMUNITIES

This section is required in every TNSNAV.ORA file. It is simply a list of the communities of which the node is a member. The COMMUNITY_LIST keyword is required only if there is more than one community.

Format of TNSNAV.ORA

This file uses the keyword-value pair syntax described for the TNSNAMES.ORA file earlier in this chapter. Groups of keyword-value pairs that logically belong together are surrounded by parentheses.

Sample LOCAL_ COMMUNITIES Entries

For example, on a client that is a member of two communities, the LOCAL_COMMUNITIES entry in TNSNAV.ORA may appear as: 

LOCAL_COMMUNITIES = (COMMUNITY_LIST =
				 (COMMUNITY = NMP.FIN.HQ.ACME)
				 (COMMUNITY = TCP.FIN.HQ.ACME))

For a client that is a member of just the Named Pipes community indicated, the following entries are equivalent:

LOCAL_COMMUNITIES = (COMMUNITY = NMP.FIN.HQ.ACME)

and

LOCAL_COMMUNITIES = (COMMUNITY_LIST =
				 (COMMUNITY = NMP.FIN.HQ.ACME))

Keywords used within PREFERRED_CMANAGERS

Within the PREFERRED_CMANAGERS section, one or more CMANAGERs are listed, specifying which Connection Managers should be used as the first hop for multi-community connections in order from most preferred to least preferred. The entry takes the form: 

PREFERRED_CMANAGERS=[(CMANAGER_LIST=] 
			    (CMANAGER= 
				(CMANAGER_NAME=cmanager_name) 
				(ADDRESS= 
				  (COMMUNITY=community_name) 
				  (PROTOCOL=protocol_ID) 
				  (protocol specific information))) 
			    [(CMANAGER= 
				(CMANAGER_NAME=cmanager_name) 
				(ADDRESS= 
				  (COMMUNITY=community_name) 
				  (PROTOCOL=protocol_ID) 
				  (protocol specific information)))]
 			  [ )]

In this syntax:

CMANAGER_LIST Indicates that one or more descriptions of a Connection Manager follow, each identified by the keyword CMANAGER. This keyword is preceded by a left parenthesis, and finished with a right parenthesis following the last Connection Manager described. Where only one CMANAGER follows, this keyword is optional.
CMANAGER Indicates that a Connection Manager is described following the keyword. The CMANAGER_NAME and the TNS address of the associated Connection Manager follow. At least one CMANAGER must be defined for any client or server that uses an Interchange.
CMANAGER_ NAME Indicates the name of a Connection Manager. (The Connection Manager and the Interchange are usually referred to by the same name.)
ADDRESS Indicates the address of the Connection Manager named in the CMANAGER_NAME parameter. Note that the Connection Manager has its own address for receiving connections on the Interchange machine. This is not the same as the address of a TNS listener if there is one on that machine.
Oracle Network Manager will supply the correct keywords and format for this configuration file; it will prompt you to supply the needed values for each CMANAGER_NAME and ADDRESS.

Sample TNSNAV.ORA File

The following sample TNSNAV.ORA file is for clients and servers in a DECnet community. There are two Interchanges available in this community. 

LOCAL_COMMUNITIES =
  (COMMUNITY_LIST =
    (COMMUNITY = DECCOM.WORLD)
  )
PREFERRED_CMANAGERS =
  (CMANAGER_LIST =
    (CMANAGER =
      (CMANAGER_NAME = INT2.WORLD)
        (ADDRESS = 
          (COMMUNITY = DECCOM.WORLD)
          (PROTOCOL = DECNET)
          (NODE = IRIS.WORLD)
          (OBJECT = CMAN)
        )
    )
    (CMANAGER =
      (CMANAGER_NAME = INT1.WORLD)
        (ADDRESS = 
          (COMMUNITY = DECCOM.WORLD)
          (PROTOCOL = DECNET)
          (NODE = DAISY.WORLD)
          (OBJECT = CMAN)
        )
    )
  )

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