2. USAGE CONSIDERATIONS › 2.3 Use Within the Information Structure › 2.3.3 Service Level Analysis › 2.3.3.1 Service Levels: Performance

2.3.3.1 Service Levels: Performance

 
Network service levels are areas of prime concern to the
management of the installation as a whole, and particularly
to the network management staff, because service levels
measure how efficiently and effectively network facilities
are delivered to the end-user.  Service levels are best
analyzed in relation to an installation-defined set of
service level objectives.  Service level objectives may be
set in different ways based on criteria that are often unique
to the installation and depend on its organization,
management objectives, and financial considerations.  Several
types of objective strategies are discussed below.
 
 
HOST SERVICE OBJECTIVES
 
Prior to the availability of end-user response time
measurements, host service objectives were the only available
management indicators of communications effectiveness.
Tivoli's NetView Performance Monitor and CA NetSpy make it
possible to measure host response time separately from
network response time, thus allowing host response objectives
to be retained.  The advantage of defining separate host
service objectives is that they can identify developing host
service problems even when end-user response time is within
the overall objectives.  Generally, host service objectives
are set on an application-by-application basis because each
application has different host processing resource
requirements.
 
 
NETWORK SERVICE OBJECTIVES
 
Network service objectives define the requirements for
delivery of service outboard of the host processor.  These
objectives are of considerable interest because, until
recently, this information was largely unavailable.  Network
service objectives must be set with regard to network
considerations rather than existing host-processor
considerations.  Two general classifications of network
service are reasonable:
 
o  Topology Based
 
   -  Communications path design constraints
 
   -  Media type constraints
      .  local versus remote
      .  link speed
      .  multi-drop versus dedicated link
      .  satellite versus land line
 
o  Resource Based
 
   -  Class of service as defined by network tuning
      parameters
 
   -  Volume of data transmitted
 
 
END-USER (TOTAL) SERVICE OBJECTIVES
 
In general, total service objectives should be close to the
sum of the applicable network and host service objectives for
each breakdown of network traffic.  Neither Tivoli's NetView
Session Monitor nor CA NetMaster NTS measures host and
network response time independently.  They each allow all of
the variations mentioned above to be accommodated through the
use of installation-defined performance classes.  NetView
performance class definitions and CA NetMaster NTS RTM class
definitions should be carefully evaluated based on the
considerations mentioned above.
 
The following sections suggest key data elements, exception
conditions, component reports, and sample analyses which may
be helpful in the management of performance levels:
 
   1 - Performance Level Indicators
   2 - Performance Level Exceptions
   3 - Performance Level Reports
   4 - Performance Level Analysis