Cisco Cisco IOS Software Release 12.0(22)S

This feature module describes the MPLS quality of service (QoS) enhancements.

The document contains the following sections:

When a customer transmits IP packets from one site to another, the IP precedence field (the first three 
bits of the DSCP field in the header of an IP packet) specifies the class of service. Based on the IP 
precedence marking, the packet is given the desired treatment such as the latency or the percent of 
bandwidth allowed. If the service provider network is an MPLS network, then the IP precedence bits are 
copied into the MPLS EXP field at the edge of the network. However, the service provider might want 
to set an MPLS packet’s QoS to a different value determined by the service offering. 

This feature allows the service provider to set the MPLS experimental field instead of overwriting the 
value in the customer’s IP precedence field. The IP header remains available for the customer’s use; the 
IP packet’s marking is not changed as the packet travels through the multiprotocol label switching 
(MPLS) network.

12.0(14)ST

This feature was introduced.

12.0(22)S

This feature was updated to support the Cisco 10720 Internet router.