QoS Policies
Quality of Service Guide 19
Table 2 presents the default definitions for the forwarding classes. The forwarding class
behavior, in terms of ingress marking interpretation and egress marking, can be changed by
a Network QoS Policies. All forwarding class queues support the concept of in-profile and
out-of-profile, and exceed-profile at egress.
The forwarding classes can be classified into three class types:
• High priority/Premium
• Assured
•Best effort
High Priority Classes
The high priority forwarding classes are Network Control (nc), Expedited (ef), High 1 (h1),
and High 2 (h2). High priority forwarding classes are always serviced at congestion points
over other forwarding classes; this behavior is determined by the router queue scheduling
algorithm (Virtual Hierarchical Scheduling).
Table 2: Forwarding Classes
FC-ID FC Name FC
Designatio
n
DiffServ
Name
Class Type Notes
7Network
Control
NC NC2 High-Priority Intended for network control traffic
6 High-1 H1 NC1 Intended for a second network control
class or delay/jitter sensitive traffic
5 Expedited EF EF Intended for delay/jitter sensitive traffic
4 High-2 H2 AF4 Intended for delay/jitter sensitive traffic
3 Low-1 L1 AF2 Assured Intended for assured traffic. Also is the
default priority for network management
traffic
2 Assured AF AF1 Intended for assured traffic
1 Low-2 L2 CS1 Best Effort Intended for BE traffic
0 Best Effort BE BE
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