SNT Performance Level Analysis
Reporting Response Time Differences For Virtual Routes
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While the nodes in the network are physically connected by real links known as explicit routes, network traffic flows over logical connections called virtual routes. These virtual routes assume the physical characteristics (media type, reliability, bandwidth, etc.) of the underlying explicit routes to which they are assigned, but the path control network schedules message units on a virtual route based on its transmission priority.
When a logical unit to logical unit (LU-LU) session is established, the session-initiation request identifies a desired class of service. The system services control point (SSCP) looks-up this class of service in the class of service (COS) table. The COS table lists virtual route and transmission priority pairs. Using the table entry for the requested class of service, the SSCP assigns a virtual route and transmission priority for the session.
Since the virtual routes and transmission priorities are the primary means the network analyst has to regulate traffic flow through the network, knowledge of the service provided to the end users communicating over a particular virtual route at a specific priority is extremely valuable when maintaining the class of service table. This information is available in the
MICS Network Analyzer
's NLDM Service File by summarizing DETAIL data from the SNTNSV File by virtual route and transmission priority as follows:%INCLUDE INCLLIB(%SNTMACS); MACRO _BY NSVVRRTE NSVTRPTY % MACRO _BREAK NSVTRPTY % PROC SORT DATA=_dSNTX.SNTNSV01 OUT=VRSERV; BY _BY; RUN; DATA VRSERV; SET VRSERV; BY _BY; _NSVSUM RUN; PROC PRINT LABELS; ID NSVVRRTE; VAR NSVTRPTY NSVAVTTM NSVPCTR1 NSVPCTR2 NSVPCTR3 NSVPCTR4 NSVPCOBM; RUN;
By determining the actual effect of specifying different transmission priorities for different virtual routes, the class of service table can be made to reflect the organization's business needs more accurately.