Cisco .
, . , BGP, .
, IPv4 , IPv4 . , , WAN NAT . , .
.
BGP , , , , . .
WAN (ISP1 ISP2 ). .
Cisco 891-K9 WAN IOS c880data-universalk9-mz.153-3.M2.bin

:
interface GigabitEthernet0 description Internet_ISP1_Main ip address 10.10.10.10 255.255.255.0 no ip proxy-arp ip nat outside // NAT interface FastEthernet8 description Internet_ISP2_Back-up ip address 100.100.100.100 255.255.255.0 no ip proxy-arp ip nat outside // NAT interface Vlan1 description Local_Area_Network ip address 192.168.1.1 255.255.255.0 ip nat inside // NAT
ACL ( ) :
ip access-list extended NAT_LAN permit ip 192.168.1.0 0.0.0.255 any
, :
route-map NAT_ISP1_Main permit 10 match ip address NAT_LAN // ACL match interface GigabitEthernet0 // WAN ! route-map NAT_ISP2_Back-up permit 10 match ip address NAT_LAN // ACL network match interface FastEthernet8 // WAN
SLA :
ip sla 1 icmp-echo 8.8.8.8 source-interface GigabitEthernet0 // DNS frequency 30 // 30 ip sla schedule 1 life forever start-time now //SLA track 1 ip sla 1 // IPSLA1
:
ip route 0.0.0.0 0.0.0.0 10.10.10.1 track 1 ip route 0.0.0.0 0.0.0.0 100.100.100.1 30
track 1 , . , 30.
NAT:
ip nat inside source route-map NAT_ISP1_Main interface GigabitEthernet0 overload ip nat inside source route-map NAT_ISP2_Back-up interface FastEthernet8 overload