Default Aliases for CoS Value Bit Patterns Overview

Behavior aggregate (BA) classifiers use class-of-service (CoS) values—such as Differentiated Services code points (DSCPs), DSCP IPv6, IP precedence, IEEE 802.1, and MPLS experimental (EXP) bits—to associate incoming packets with a particular CoS servicing level (forwarding class and packet loss priority (PLP)). You can assign a meaningful name or alias to the CoS values and use this alias instead of bits when configuring CoS components. These aliases are not part of the specifications but are well known through usage. For example, the alias for DSCP 101110 is widely accepted as ef (expedited forwarding).

When you define classifiers, you can refer to the markers by alias names. You can configure user-defined classifiers in terms of alias names. If the value of an alias changes, it alters the behavior of any classifier that references it.

Table 1 shows the default mappings between the CoS values and standard aliases.