HP VPN Firewall Appliances High Availability Configuration Guide

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• Cluster—A cluster that provides network traffic load balancing, consisting of an LB device and
physical links
• LB device—A device that distributes traffic to multiple physical links.
• Physical links—Links provided by carriers.
• VSIP—Virtual service IP address provided by the cluster, or, the destination segment of the packets
sent by users.
Figure 92 Work flow of outbound link load balancing
Outbound link load balancing operates in the following way:
1. The LB device receives the traffic from the internal users.
2. The LB device selects a link according to the destination IP address and the outbound link load
balancing rules configured.
3. The LB device forwards the traffic to the selected link.
4. The LB device receives the traffic sent from the external users.
5. The LB device forwards the traffic to the internal users.
Inbound link load balancing
Figure 93 Network diagram
Inbound link load balancing comprises the following elements:
LB device
(1) Traffic from source
Source Destination
(3) Distribute
(4) Traffic from destination
(5) Forward
(2) Scheduler
Local DNS
server A
Local DNS
server B
LB device
Cluster
ISP1
ISP3
ISP2IP network
Router A
Router B
Router C