Example for Connecting a Device to an NLB Cluster Working in IGMP Multicast Mode (Using Multi-Interface ARP)

Networking Requirements

As shown in Figure 1, the Switch connects to three NLB servers through three interfaces in VLAN 10: GE0/0/1, GE0/0/2, and GE0/0/3. The NLB cluster works in IGMP multicast mode. Each server in the NLB cluster has an IP address and a MAC address. All servers in the cluster share the cluster IP address (10.128.246.252/24) and cluster MAC address (0100-5e00-0002). There are reachable routes between the Switch and Client.

The customer requires that the Switch send the packet destined for the cluster IP address to each server in the NLB cluster.

Figure 1 Networking diagram for configuring multi-interface ARP

Configuration Roadmap

The configuration roadmap is as follows:

Create a VLAN and add interfaces to the VLAN. Configure an IP address for the VLANIF interface.
Configure the Switch to forward multicast data in the VLAN based on MAC addresses and enable IGMP snooping in the VLAN so that the Switch can dynamically learn the MAC address entry mapping multiple outbound interfaces.
Configure a static ARP entry to enable the Switch to send the packet destined for the cluster IP address to all the three servers in the NLB cluster.

Procedure

Create a VLAN and add interfaces to the VLAN.

# Create a VLAN on the Switch and add interfaces to the VLAN.

<HUAWEI> system-view
[HUAWEI] sysname Switch
[Switch] interface gigabitethernet 0/0/1
[Switch-GigabitEthernet0/0/1] port link-type access
[Switch-GigabitEthernet0/0/1] quit
[Switch] interface gigabitethernet 0/0/2
[Switch-GigabitEthernet0/0/2] port link-type access
[Switch-GigabitEthernet0/0/2] quit
[Switch] interface gigabitethernet 0/0/3
[Switch-GigabitEthernet0/0/3] port link-type access
[Switch-GigabitEthernet0/0/3] quit
[Switch] vlan 10
[Switch-vlan10] port gigabitethernet 0/0/1 to 0/0/3
[Switch-vlan10] quit

# Create a VLANIF interface on the Switch and assign an IP address to the VLANIF interface.

[Switch] interface vlanif 10
[Switch-Vlanif10] ip address 10.128.246.251 24
[Switch-Vlanif10] quit

Enable IGMP snooping globally on the Switch.
```
[Switch] igmp-snooping enable
```

Configure the Switch to forward multicast data in the VLAN based on MAC addresses and enable IGMP snooping in the VLAN.

[Switch] vlan 10
[Switch-vlan10] l2-multicast forwarding-mode mac
[Switch-vlan10] igmp-snooping enable
[Switch-vlan10] quit

Configure a static ARP entry on the Switch.

[Switch] arp static 10.128.246.252 0100-5e00-0002
[Switch] quit

Verify the configuration.

# Display the MAC address entry mapping multiple outbound interfaces learned through protocol packets on the Switch. According to the command output, the MAC address of the IGMP multicast cluster is 0100-5e00-0002, the outbound interfaces are GigabitEthernet0/0/1, GigabitEthernet0/0/2, and GigabitEthernet0/0/3, and the VLAN ID of packets is 10.

<Switch> display l2-multicast forwarding-table vlan 10
VLAN ID : 10, Forwarding Mode : MAC                                                                                                 
Total Group(s) : 1                                                                                                                  
--------------------------------------------------------------------------------                                                    
Group(Mac)                                  Interface                Out-Vlan                                                       
--------------------------------------------------------------------------------                                                    
0100-5e00-0002                              GigabitEthernet0/0/1        10                    
                                            GigabitEthernet0/0/2        10                    
                                            GigabitEthernet0/0/3        10                    
--------------------------------------------------------------------------------

# Display information about the static ARP entry.

<Switch> display arp static
IP ADDRESS      MAC ADDRESS     EXPIRE(M) TYPE        INTERFACE   VPN-INSTANCE 
                                    VLAN/CEVLAN(SIP/DIP)
------------------------------------------------------------------------------
10.128.246.252  0100-5e00-0002            S--         Multi-port:3            
------------------------------------------------------------------------------
Total:1        Dynamic:0      Static:1     Interface:0

Configuration Files

Switch configuration file

#
sysname Switch
#
vlan batch 10 
#                                                                                                                                   
igmp-snooping enable                                                                                                                
#                                                                                                                                   
vlan 10                                                                                                                             
 l2-multicast forwarding-mode mac                                                                                                   
 igmp-snooping enable                                                                                                               
#
interface Vlanif10
 ip address 10.128.246.251 255.255.255.0
#
interface GigabitEthernet0/0/1
 port link-type access
 port default vlan 10
#
interface GigabitEthernet0/0/2
 port link-type access
 port default vlan 10
#
interface GigabitEthernet0/0/3
 port link-type access
 port default vlan 10
#
arp static 10.128.246.252 0100-5e00-0002
#
return