ZyXEL Communications ONU-2024 Series, User Manual

Page: 182 / 268

Chapter 24 Differentiated Services
ONU User’s Guide
182
The DSCP value determines the PHB (Per-Hop Behavior), that each packet gets as it is
forwarded across the DiffServ network. Based on the marking rule different kinds of traffic
can be marked for different priorities of forwarding. Resources can then be allocated
according to the DSCP values and the configured policies.
DiffServ Network Example
The following figure depicts a DiffServ network consisting of a group of directly connected
DiffServ-compliant network devices. The boundary node (
A in Figure 95 ) in a DiffServ
network classifies (marks with a DSCP value) the incoming packets into different traffic flows
(
Platinum , Gold , Silver , Bronze ) based on the configured marking rules. A network
administrator can then apply various traffic policies to the traffic flows. An example traffic
policy, is to give higher drop precedence to one traffic flow over others. In our example,
packets in the
Bronze traffic flow are more likely to be dropped when congestion occurs than
the packets in the Platinum traffic flow as they move across the DiffServ network.
Figure 95 DiffServ Network
G S B P
S
B
B
G P P S
P - Platinum
G - Gold
S - Silver
B - Bronze
G P P S
A