Network ingress traffic originates from a network egress port located on another interworking device, such as a 7710 or 7750 Service Router or another 7705 SAR, and flows from the network toward the fabric in the 7705 SAR.
The ingress MPLS packets can be mapped to forwarding classes based on EXP bits that are part of the headers in the MPLS packets. These EXP bits are used across the network to ensure an end-to-end network-wide QoS offering. With pseudowire services, there are two labels, one for the MPLS tunnel and one for the pseudowire. Mapping is performed using the EXP values from the outer tunnel MPLS label. This ensures that the EXP bit settings, which may have been altered along the path by the tandem label switch routers (LSRs), are used to identify the forwarding class of the encapsulated traffic.
Ingress GRE and IP packets are mapped to forwarding classes based on DSCP bit settings of the IP header. GRE tunnels are not supported for IPv6; therefore, DSCP bit classification of GRE packets is only supported for IPv4. DSCP bit classification of IP packets is supported for both IPv4 and IPv6.
Untrusted traffic uses multi-field classification (MFC), where the traffic is classified based on any IP criteria currently supported by the 7705 SAR filter policies; for example, source and destination IP address, source and destination port, whether or not the packet is fragmented, ICMP code, and TCP state. For information on MFC, refer to the 7705 SAR Router Configuration Guide, ‟Multi-field Classification (MFC)” and ‟IP, MAC, and VLAN Filter Entry Commands”.