Ernest G. Wilson II's QoS (Quality of Service) guide for Avaya QoS and Cisco QoS

       QoS (Quality of Service) and it's counterpart CoS (Class of Service) is absolutely essential to a successful VoIP (Voice over IP) implementation.
There is nothing true (or funny, although it makes me laugh when I hear it) in saying your network has "enough bandwidth" that you don't need QoS.
Every successful and reliable implementation of Voice over IP must include an "end to end" QoS solution.
When you gamble with bandwidth, it is not "if" but rather "when" will your network cause unacceptable voice quality?

Q. What is QoS?
A. Simply put: When your network makes sure "Real Time" voice traffic gets priority over other traffic when you need it most!
    A more detailed answer would say:
        - Marking special voice (and video) RTP (Real Time Protocol) and control traffic frames and packets
        - Having your switches and routers recognize these special CoS and QoS markings and prioritize them correctly
        - Guaranteeing bandwidth and priority for voice and video ahead of other traffic like email and file transfers

        I am very satisfied (and proud) with my current QoS configuration for the most part.  It has been a steep learning curve but very rewarding.
Our Avaya phone system and Cisco network gear correctly identifies and prioritizes voice and video traffic and using a carefully designed QoS system.
As such, I want to share some of the information I put together when designing our Avaya QoS system.  This most basic information was earned the hard
way by me over time as I did not have the luxury of a straight forward document detailing how an Avaya phone system should interact with a Cisco network.

Without further ado, here is my:
Ernest G. Wilson II's QoS (Quality of Service) guide for Avaya QoS and Cisco QoS in MS Doc format.
Please use at your own risk!