are also three user-defined TG characteristics. Youmay define these user-defined
TG characteristics in order to bias the route selection calculation in favor of certain
paths.
Note: For DLSw ports the TG characteristics that you define effect only the
selection of routes between APPN nodes over these DLSw ports. These
characteristics have no direct effect on any intermediate routing performed
by DLSw on APPN’s behalf.
COS Options
Youcan use a template to create new user-defined COS names and associated
definitions for TGs and nodes which can be used with new mode names or mapped
to existing mode names.
In addition you can create new mode names that can be mapped to existing COS
names.
Each COS definition file is identified by a COS name and contains an associated
transmission priority and a table of ranges of acceptable TG and node
characteristics that APPN compares against actual TG and node characteristics to
determine weights for TGs and nodes from which APPN calculates the least weight
route for the session. Using the Configuration Program you can:
vView a COS definition file:
– View the transmission priority
– View a list of node row references along with their corresponding weights
– View a list of TG row references along with their corresponding weights
vSelect standard or ATMCOS tables as templates to define a new user-defined
COS definition file with a new COS name:
– Import an IBM-defined COS definition file to use as a template
– Import a previously exported user-defined COS definition file to use as a
template
vDefine the minimum and maximum ranges for the user-defined TG characteristics
within an IBM-defined COS definition.
Note: In an IBM-defined COS definition you can edit only the user-defined TG
characteristic ranges.
Using Configuration Program or talk 6 you can:
vUse standard COS tables or the Enhanced COS tables (for ATM).
vDefine a new mode name and its mapping to a COS name.
vChange a mode name to COS name mapping:
– Re-map an IBM-defined mode name to a different COS name.
– Re-map a previously specified user-defined mode name to a different COS
name.
Refer to the discussion of Topologyand Routing Services in the

SNA APPN

Architecture Reference

, SC30–3422, for a description of standard and ATMCOS
tables.
APPN Node Tuning
The performance of the router APPN network node can be tuned in two ways:
APPN
38 MRS V3.2 Protocol Config Ref Vol2