Characteristics of Physical Layer Optimization Problems
Performance lower than baseline

If there is a problem with sub-optimal operation at the physical layer, the network may be operational, but performance will be consistently or intermittently lower than the level specified in the baseline.

If performance is unsatisfactory all the time, then the problem is probably related to a poor configuration, inadequate capacity somewhere, or some other systemic problem. If performance varies and is not always unsatisfactory, then the problem is probably related to an error condition or is being affected by traffic from other sources:

  • Unstable routing due to a marginal port or link somewhere beyond the broadcast domain, possibly the result of a bad cable
  • Excessive traffic across a low speed LAN or WAN link, possibly causing traffic to be discarded or buffer capacity to be exceeded
  • Overloaded server or service

A physical layer optimization problem occurs when the physical properties of the connection are substandard, causing data to be transferred at a rate that is consistently less than the rate of data flow established in the baseline.


Lab Activity

Lab Exercise: Applying a Logical Layered Model to a Physical Network

After completing this lab, the student will be able to understand the data flow in the classroom network based on the logical network model.