Step 1: Identifying traffic types and their requirements
Identifying traffic types and their requirements, the first step in implementing QoS, is composed
of the following elements or substeps:
Perform a network audit -- It is often recommended that you perform the audit during the
busy hour (BH) or congestion period, but it is also important that you run the audit at other
times. Certain applications are run during slow business hours on purpose. There are scientific
methods for identifying the busy network moments, for example, through statistical sampling
and analysis, but the simplest method is to observe CPU and link utilizations and conduct the
audit during the general peak periods.
Perform a business audit and determine the importance of each application -- The
business model and goals dictate the business requirements. From that, you can derive the
definition of traffic classes and the requirements for each class. This step considers whether
delaying or dropping packets of each application is acceptable. You must determine the
relative importance of different applications.
Define the appropriate service levels for each traffic class -- For each traffic class, within
the framework of business objectives, a specific service level can define tangible resource
availability or reservations. Guaranteed minimum bandwidth, maximum bandwidth, guaranteed
end-to-end maximum delay, guaranteed end-to-end maximum jitter and comparative drop
preference are among the characteristics that you can define for each service level. The final
service level definitions must meet business objectives and satisfy the comfort expectations
of the users.
Go to Step 2: Classifying traffic based on the requirements identified
Reproduced from the book CCNP ONT Official Exam Certification Guide Copyright [2007], Cisco Systems, Inc. Reproduced by permission of Pearson Education, Inc., 800 East 96th Street, Indianapolis, IN 46240. Written permission from Pearson Education, Inc. is required for all.
