Everybody needs today Quality of Service, but one only
has some difuse ideas about
what is Quality of Service is in real. All of this because
the term Quality is
diferent for a end user and for the business man, or
even for the Internet Service Provider.
At the IETF, they made an enforcement to define and create
some parameters, which give
us some classes called Classes of Service. These classes
are defined by parameters
such as: delays, bandwidth, losses, etc. Is very dificult
to implement this Classes
of Service because the number and type or style of the
networks are so diferent.
Actualy the most important protocols toward's to implementation
of Quality of Service
are known as: RSVP, AREQUIPA, Diffserv and Integrated
Services and ATM itself.
All of these have some limitations and some advantages,
but noone of them can
leed us to full Quality of Service. They clearly show
that the networks we use today
are still far away of the Quality that applications would
expect.
The deployment of an architecture to implement the Diffserv
services gave us some
interesting results.
This architecture, using the ALTQ (tool provided by Kenjiro
Cho), uses a router with
some rules of Diffserv, to classify and mark the packets.
These packets are processed
in a queue with CBQ. Each queue implements a class with
a proper bandwidth.
The tool ALTQ has been modified to give us some samples
in diferent stages within
n the router, with diferent traffics and bandwidth.
The results obtained by these tests gave us the idea
we can accomplish Quality of
Service with this architecture Diffserv.