VPLS Scenario
VPLS Typical Topology
Figure 1 VPLS typical topology
- PE (provider edge): an edge device on the provider network, which is directly connected to the CE. The PE receives traffic from the CE and then encapsulates the Ethernet traffic with MPLS header, and then sends the traffic to P. The PE also receives traffic from the P and then remove the MPLS header from the traffic, and then sends the traffic to CE.
- P (Provider): a backbone device on the provider network, which is not directly connected to the CE. Ps perform basic MPLS forwarding.
- CE (customer edge): an edge device on the private network. CEs perform Ethernet/VLAN layer2 forwarding.
Suitable Scenario 1: Load Balance on Ingress PE of VPLS
Figure 2 Route load balance on ingress PE
Figure 3 Trunk load balance on ingress PE
Figure 4 Tunnel load balance on ingress PE
The hash algorithm is performed based on the packet format of
the inbound traffic from AC interface.
- IP traffic: the hash factors can be IP 5-tuple or IP 2-tuple. The result of the load balancing depends on the discreteness of the private IP addresses or TCP/UDP ports of the packets.
- Ethernet carrying Non-IP traffic, the hash factors can be MAC 2-tuple. The result of the load balancing depends on the discreteness of the MAC addresses of the packets. Some kind of board supports 3-tuple <source MAC, destination MAC, VC Label> if the inbound AC traffic is MPLS traffic and the AC interface is not QinQ sub-interface.
Suitable Scenario 2: Load Balance on P Node
Figure 5 Route load balance on P
Figure 6 Trunk load balance on P
The hash algorithm on P node is performed based on the packet
format of the inbound MPLS traffic.
- If the number of labels in the packet is less than four, the hash factors can be IP 5-tuple or IP 2-tuple. The result of the load balancing depends on the discreteness of the private IP addresses or TCP/UDP ports of the packets.
- In the complex scenarios such as inter-AS VPN, FRR and LDP over TE, the number of the labels may be four or more. In these scenarios, the hash factors are the layer 4 or layer 5 label. The result of the load balancing depends on the discreteness of the layer 4 or layer 5 labels of the packets.
Suitable Scenario 3: Load Balance on Egress PE of VPLS
Egress PE of VPLS only supports Trunk load balancing because the Egress PE performs Ethernet/VLAN layer2 forwarding. There is no route load balancing on egress PE of VPLS.
Figure 7 Trunk load balance on egress PE
- If the traffic is from MPLS to AC, the hash factors can be IP 5-tuple, IP 2-tuple or MAC 2-tuple. The default hash factors may be different in different board-types. Some boards only support MAC 2-tuple.
- If the traffic is from AC to AC, the hash algorithm is the same as Scenario 1.
Suitable Scenario 4: Load Balancing Among the L2 Outbound Interfaces in the Access of L2VPN to L3VPN Scenarios
Figure 8 Load Balancing Among the L2 Outbound Interfaces in the Access
of L2VPN to L3VPN Scenarios
In access of L2VPN to L3VPN scenarios, the hash algorithm is the same as Scenario 1.