H3C Technologies H3C SecPath F1000-E - Manual (Page 874)

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Inbound link load balancing includes the following basic elements:
• Cluster: A cluster that provides network traffic load balancing, consisting of an LB device, physical
links, and local DNS servers.
• LB device: Working as an authoritative name server of the domain name to be resolved, an LB
device is used to select an optimal path for the traffic from extranet to intranet.
• Physical links: Links provided by carriers.
• Local DNS server: A local DNS server that resolves the DNS requests sent by a host.
Figure 11 shows the work flow of inbound link load balancing.
Figure 11 Work flow of inbound link load balancing
The following describes the work flow of inbound link load balancing:
1. An extranet user sends a DNS request to its local DNS server for DNS resolution before resource
access.
2. The local DNS server converts the source IP address of the DNS request to its own IP address, and
forwards it to the authoritative name server, namely, the LB device.
3. The LB device resolves the domain name according to the domain name of the DNS request and
the configured inbound link load balancing rules.
4. The LB device sends the DNS response to the local DNS server according to the DNS resolution
result.
5. The local DNS server forwards the DNS resolution result to the user.
6. The user uses the link selected to access the LB device.
Configuring Server/Firewall Load Balancing
NOTE:
The configuration of firewall load balancing is similar to that of server load balancing. Configuration of
server load balancing is introduced here.