Networking Requirements

In Figure 1, a small-sized enterprise deploys a router as an access gateway to provide Internet access for intranet users. To prevent network congestion when the network traffic is heavy, the enterprise deploys two uplinks on the router to connect to the Internet. Both links are connected to ISP networks through static IP addresses. To improve the network bandwidth, the enterprise requires that the Internet access traffic of intranet users be evenly forwarded on the two links. In addition, the enterprise requires that NAT be configured to enable intranet users to access the Internet.

Figure 3-17 Configuring dual-uplink Internet access using static IP addresses for load balancing

Data Preparation

Configuration Roadmap

1. Configure a static IP address for GE0/0/1 on link 1 so that intranet users can access ISP 1 using this static IP address through link 1.
2. Configure a static IP address for GE0/0/2 on link 2 so that intranet users can access ISP 2 using this static IP address through link 2.
3. Configure outbound NAT in Easy IP mode on the two uplink interfaces on the router so that intranet users can access the Internet.
4. Configure two equal-cost default routes to load balance traffic over the two links.

Procedure

1. Configure a static IP address for GE0/0/1 on link 1 so that intranet users can access ISP 1 using this static IP address through link 1.

   [Router] interface gigabitethernet 0/0/1 
   [Router-GigabitEthernet0/0/1] undo portswitch   //Some Layer 2 interfaces can have static IP addresses configured only after their working mode is changed to Layer 3. 
   [Router-GigabitEthernet0/0/1] ip address 172.16.1.1 24    //Configure the IP address assigned by ISP 1 for the interface on link 1. 
   [Router-GigabitEthernet0/0/1] quit

2. Configure a static IP address for GE0/0/2 on link 2 so that intranet users can access ISP 2 using this static IP address through link 2.

   [Router] interface gigabitethernet 0/0/2 
   [Router-GigabitEthernet0/0/2] undo portswitch    
   [Router-GigabitEthernet0/0/2] ip address 10.1.1.1 24 //Configure the IP address assigned by ISP 2 for the interface on link 2. 
   [Router-GigabitEthernet0/0/2] quit
   [Router] interface gigabitethernet 0/0/3 
   [Router-GigabitEthernet0/0/3] undo portswitch    
   [Router-GigabitEthernet0/0/3] ip address 192.168.1.1 24   //Configure an IP address for the router's downlink interface connected to the intranet.
   [Router-GigabitEthernet0/0/3] quit

3. Configure outbound NAT in Easy IP mode on the two uplink interfaces on the router so that intranet users can access the Internet.

   [Router] acl number 3002
   [Router-acl-adv-3002] rule 5 permit ip source 192.168.1.0 0.0.0.255  //Allow only users on the 192.168.1.0 network segment to access the Internet. 
   [Router-acl-adv-3002] quit
   [Router] interface gigabitethernet 0/0/1               
   [Router-GigabitEthernet0/0/1] nat outbound 3002
   [Router-GigabitEthernet0/0/1] quit
   [Router] interface gigabitethernet 0/0/2     
   [Router-GigabitEthernet0/0/2] nat outbound 3002
   [Router-GigabitEthernet0/0/2] quit

4. Configure two equal-cost default routes to load balance traffic over the two links based on source IP addresses.

   [Router] ip route-static 0.0.0.0 0 172.16.1.2 //Set the priority of the route over link 1 to the default value 60. 
   [Router] ip route-static 0.0.0.0 0 10.1.1.2 //Set the priority of the route over link 2 to the default value 60. The two default routes have the same cost value. 
   [Router] ip load-balance hash src-ip //Configure load balancing based on source IP addresses. 
   [Router] quit

Verifying the Configuration

1. Run the display ip routing-table protocol static command on the router to check static routes in its IP routing table. The routing table contains two equal-cost default routes destined to ISP 1 and ISP 2, respectively.

   <Router> display ip routing-table protocol static                                
   Route Flags: R - relay, D - download to fib, T - to vpn-instance                
   ------------------------------------------------------------------------------  
   Public routing table : Static                                                   
            Destinations : 1        Routes : 2        Configured Routes : 2        
   
   Static routing table status : <Active>                                          
            Destinations : 0        Routes : 0                                     
   
   Static routing table status : <Inactive>                                        
            Destinations : 1        Routes : 2                                     
   
   Destination/Mask    Proto   Pre  Cost      Flags NextHop         Interface      
   
           0.0.0.0/0   Static  60   0               172.16.1.2      Unknown        
           0.0.0.0/0   Static  60   0               10.1.1.2        Unknown 

2. Run the ping command on HostA to ping the IP address of each ISP's gateway. This simulates the scenario where an intranet host accesses the Internet. HostA can ping the IP addresses of the gateways of ISP 1 and ISP 2 at the same time and the Internet access traffic can be load balanced over the two links.

Configuration File

#
 sysname Router
#                                                                               
ip load-balance hash src-ip
#
acl number 3002  
 rule 5 permit ip source 192.168.1.0 0.0.0.255   
#
interface GigabitEthernet0/0/1                                                  
 undo portswitch                                                                
 ip address 172.16.1.1 255.255.255.0                                            
 nat outbound 3002
#
interface GigabitEthernet0/0/2                                                  
 undo portswitch                                                                
 ip address 10.1.1.1 255.255.255.0                                              
 nat outbound 3002 
#
interface GigabitEthernet0/0/3                                                  
 undo portswitch                                                                
 ip address 192.168.1.1 255.255.255.0                                           
# 
ip route-static 0.0.0.0 0.0.0.0 172.16.1.2                                      
ip route-static 0.0.0.0 0.0.0.0 10.1.1.2
#
return