出链路负载均衡如何实现链路组间的备份

如无特别说明，描述中的FW1对应拓扑中设备名称末尾数字为1的设备，R2对应拓扑中设备名称末尾数字为2的设备，以此类推.

MSR2的loopback口地址代表三个内网地址，访问外网地址100.1.1.1，分别从三个运营商链路出去。

如图所示：FW1作为出口防火墙，对外分别有移动、联通、电信的三条链路。

需求：

1. 三条链路实现负载分担的效果，即针对不通的流量分别走三条链路。模拟器环境配置三个不同源地址分别走三个出口，模拟ISP选路规则。

2. 三条链路能够互为备份，即某一条链路故障时，可以切换到另外一条上面去。

R2、R3、R4和R5的配置略过，按照图示配置对应IP和路由即可。

R2的网关在FW上，FW上有去往100.1.1.1的路由。

FW配置如下：

1. IP、路由、安全域配置

#             

interface GigabitEthernet1/0/0

 port link-mode route

 combo enable copper

 ip address 10.1.1.1 255.255.255.0

#

interface GigabitEthernet1/0/1

 port link-mode route

 combo enable copper

 ip address 1.1.1.1 255.255.255.0

 nat outbound

#

interface GigabitEthernet1/0/2

 port link-mode route

 combo enable copper

 ip address 2.2.2.1 255.255.255.0

 nat outbound

#

interface GigabitEthernet1/0/3

 port link-mode route

 combo enable copper

 ip address 3.3.3.1 255.255.255.0

 nat outbound

#

security-zone name Trust

 import interface GigabitEthernet1/0/0

#

security-zone name Untrust

 import interface GigabitEthernet1/0/1

 import interface GigabitEthernet1/0/2

 import interface GigabitEthernet1/0/3

#

 ip route-static 100.1.1.0 24 1.1.1.3

 ip route-static 100.1.1.0 24 2.2.2.4

 ip route-static 100.1.1.0 24 3.3.3.5

 ip route-static 172.0.0.0 8 10.1.1.2

#

security-policy ip

 rule 0 name any

  action pass

  counting enable

#

2. LB部分

#

nqa template icmp t1

#

loadbalance link-group lg      //作为备份链路

 transparent enable

 success-criteria at-least 1

 link cmcc

  probe t1

 link cnc

  probe t1

 link cucc

  probe t1

#             

loadbalance link-group lg-cmcc

 fail-action reschedule

 transparent enable

 success-criteria at-least 1

 link cmcc

#

loadbalance link-group lg-cnc

 fail-action reschedule

 transparent enable

 probe t1

 success-criteria at-least 1

 link cnc

#

loadbalance link-group lg-cucc

 fail-action reschedule

 transparent enable

 probe t1

 success-criteria at-least 1

 link cucc

#

loadbalance class c-cmcc type link-generic

 match 1 source ip address 172.1.1.0 24

#             

loadbalance class c-cnc type link-generic

 match 1 source ip address 172.2.2.0 24

#

loadbalance class c-cucc type link-generic

 match 1 source ip address 172.3.3.0 24

#

loadbalance action a-cmcc type link-generic

 link-group lg-cmcc backup lg

 fallback-action continue

#

loadbalance action a-cnc type link-generic

 link-group lg-cnc backup lg

 fallback-action continue

#

loadbalance action a-cucc type link-generic

 link-group lg-cucc backup lg

 fallback-action continue

#

loadbalance action default type link-generic

 forward all

#

loadbalance policy lb type link-generic

 class c-cmcc action a-cmcc

 class c-cnc action a-cnc

 class c-cucc action a-cucc

 default-class action default

#

virtual-server vs type link-ip

 virtual ip address 0.0.0.0 0

 lb-policy lb

 service enable

#

loadbalance link cmcc

 router ip 1.1.1.3

 probe t1

#

loadbalance link cnc

 router ip 2.2.2.4

 probe t1

#

loadbalance link cucc

 router ip 3.3.3.5

 probe t1

#