The user-satisfaction (US) is related to a number of parameters
(success Suc, jitter 
, price P, end-to-end delay EED,
synchronization skew 
, startup latency sL and loss-rate lR).
In each QoS class, the success of a request, Suc, is defined
differently, since, for example deterministic services must meet stricter
performance
requirements (e.g. throughput and delay) than best-effort traffic.
For example, in a system with admission control, success of a request
Suc could be determined by whether the request has been admitted.
With best effort traffic, a request is always admitted and hence success
could be used to measure whether the request successfully ran to completion.
For our study, we assume the presence of an admission control process,
and focus on representing and measuring the QoS of a request once it has
been admitted, hence Suc is a constant.
While the startup latency sL impacts user-satisfaction, it is a
non-continuous one-time factor, i.e., it is measured once per session or
request and does not impact inter-frame displays.
To simplify Equation 2, the parameters
loss rate (lR) and end-to-end delay (EED)
can be subsumed by the jitter parameter ( ).
We will come back to the issue of price (P) in Section 0.2.
The simplified relation is:
where 
is a function that represents the relationship between
jitter, price and synchronization skew.
Furthermore, there exists a strong relationship between the jitter ( )
and the synchronization skew ( ).
(1) Jitter between two consecutive packet pairs is defined as
follows:
The objective is to minimize and
achieve 
at the destination d if possible.
(2) Delay 
of a link:
consists of a sum of propagation delay
(DPROP),
queueing delay (DQUEUE), and switching delay (DSWITCH).
The propagation delay and switching delay are constant, hence
the only variable is the queueing delay. The queueing delay can be
calculated according
to Little's formula 
.
The arrival rate 
at node i depends on jitter built up from the
source till node i-1,
(i.e. 
), therefore
queueing delay depends on jitter, 
,
hence delay on link depends on jitter,
(3) Skew :
Let 
and 
be time points of two packets from different media
which should be synchronized in the same time interval.
Let us assume 
as arrival times at the destination
with 
as departure times at the source:
This equation shows the dependency between jitter parameter and the synchronization skew.
