VLAN mapping application scenarios
One-to-one and many-to-one VLAN mapping
Figure 79 shows a typical application scenario of one-to-one and many-to-one VLAN mapping. The scenario implements broadband Internet access for a community.
Figure 79: Application scenario of one-to-one and many-to-one VLAN mapping
As shown in Figure 79, the network is implemented as follows:
Each home gateway uses different VLANs to transmit the PC, VoD, and VoIP services.
To further subclassify each type of traffic by customer, configure one-to-one VLAN mapping on the wiring-closet switches. This feature assigns a separate VLAN to each type of traffic from each customer. The required total number of VLANs in the network can be very large.
To prevent the maximum number of VLANs from being exceeded on the distribution layer device, configure many-to-one VLAN mapping on the campus switch. This feature assigns the same VLAN to the same type of traffic from different customers.
One-to-two and two-to-two VLAN mapping
Figure 80 shows a typical application scenario of one-to-two and two-to-two VLAN mapping. In this scenario, the two remote sites of the same VPN must communicate across two SP networks.
Figure 80: Application scenario of one-to-two and two-to-two VLAN mapping
Site 1 and Site 2 are in VLAN 2 and VLAN 3, respectively. The SP 1 network assigns SVLAN 10 to Site 1. The SP 2 network assigns SVLAN 20 to Site 2. When the packet from Site 1 arrives at PE 1, PE 1 tags the packet with SVLAN 10 by using one-to-two VLAN mapping.
When the double-tagged packet from the SP 1 network arrives at the SP 2 network interface, PE 3 processes the packet as follows:
Replaces SVLAN tag 10 with SVLAN tag 20.
Replaces CVLAN tag 2 with CVLAN tag 3.
One-to-two VLAN mapping provides the following benefits:
Enables a customer network to plan its CVLAN assignment without conflicting with SVLANs.
Adds a VLAN tag to a tagged packet and expands the number of available VLANs to 4094 × 4094.
Reduces the stress on the SVLAN resources, which were 4094 VLANs in the SP network before the mapping process was initiated.