Huawei quidway s7700 Configuration Manual page 240

Quidway S7700 Smart Routing Switch
Configuration Guide - SPU
Figure 6-4 Typical networking of firewall load balancing
HostA
As shown in
responsible for allocating traffic of user requests to multiple firewalls. Load balancing devices
are classified into level-1 and level-2 load balancing devices. Level-1 load balancing devices
load balance traffic on the firewalls, and level-2 load balancing devices ensure that the inbound
and outbound traffic traverses the same firewall. As shown in
Host A to Host B, Switch A is the level-1 load balancing device and Switch B is the level-2 load
balancing device; if traffic is sent from Host B to Host A, then Switch B is the level-1 load
balancing device and Switch A is the level-2 load balancing device. The firewall load balancing
process is as follows:
1.
2.
3.
4.
5.
6.
According to different networking modes, firewalls are classified into standard firewalls and
transparent firewalls.
l
Issue 01 (2011-07-15)
IP
Network
Figure 6-4, Switch A and Switch B function as load balancing devices and are
Host A sends a request to Host B.
After receiving the request packet of Host A, Switch A selects a firewall (assume that
Firewall A is used) according to the load balancing algorithm and forwards the request
packets to Firewall A.
Firewall A forwards the request packet to Switch B.
As the level-2 load balancing device, Switch B records the firewall forwarding the request
packet and forwards the request packet to the destination (Host B shown in
After receiving the response packet of Host B, Switch B forwards the response packet to
Firewall A according to the record.
Firewall A forwards the response packet to Switch A and Switch A returns the received
response packet to Host A.
Each standard firewall, which is similar to a server, has an IP address. The standard firewall
can be detected by other devices on networks, as shown in
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FirewallA
Switch
A
Firewall
B
6 Load Balancing Configuration
SwitchB
IP
Network
Figure 6-4, if traffic is sent from
Figure 6-5.
HostB
Figure 6-4).
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