DSCP Preserve Per-VRF

This method of configuration allows Network operator to enable or disable DSCP preserve for specific L3 VPN services in an edge router.

DSCP Preserve Per-VRF Characteristics

The MPLS cloud connects edge routers that provision L3 VPN services for multiple customers. Each edge router can support multiple VPN services, with different QoS (DSCP) remarking needs. Some customers may want to retain the DSCP field in the IP header, while others may need to update it as traffic enters the MPLS network. By default, the DSCP field in customer packets is not preserved when remarking occurs.

Figure 70. DSCP Preserve Topology

Prerequisites

The L3VPN service will operate seamlessly from end to end without any packet loss, using either OSPF or IS-IS as the IGP, with traffic profiles configured based on user-defined DSCP values.

Global level configuration for PE1:

    config t
    qos enable
    !
    qos profile dscp-to-queue profile1
    dscp 24 queue 3 dscp 32

interface level configuration for PE1:

    interface xe3
    qos map-profile dscp-to-queue profile1
    !