206Figure 72 Many-to-one VLAN mapping implementationEach DHCP snooping entry contains information about one DHCP client, including its IP address, MACaddress, and CVLAN. For more information about DHCP snooping, see Layer 3—IP ServicesConfiguration Guide.Two-to-two VLAN mappingImplement two-to-two VLAN mapping through the following configurations, as shown in Figure 73.• For uplink traffic, apply an inbound policy on the customer-side port to replace the SVLAN with anew SVLAN, and apply an outbound policy on the network-side port to replace the CVLAN with anew CVLAN.• For downlink traffic, apply an outbound policy on the customer-side port to replace the double tagswith the original VLAN tag pair.Figure 73 Two-to-two VLAN mapping implementationVLAN mapping configuration tasksUse the VLAN mapping methods as appropriate to the roles of your switches in the network, as describedin this table:Task Switch roleConfiguring one-to-one VLAN mapping Wiring-closet switchConfiguring many-to-one VLAN mapping Campus switchConfiguring two-to-two VLAN mapping Edge switch between SP networksNetwork-side port Customer-side port Uplink traffic Downlink trafficSP networkOutbounddownlink policySVLAN DataCVLANSVLAN DataCVLANOutbounduplink policyInbounduplink policyDataCVLAN’SVLAN’DataCVLAN’SVLAN’Customernetwork
