Connecting a Device to an NLB Cluster (Using Multi-Interface ARP)

Context

After multi-interface ARP is configured, a device can send the packet destined for the cluster IP address to each server in the NLB cluster. All servers in an NLB cluster use the same cluster IP address and cluster MAC address. When a device is directly connected to NLB servers and functions as their access gateway, the device sends a packet from clients to the cluster IP address, where it is forwarded to every server in the NLB cluster. The servers themselves determine whether to process the packet.

When the NLB cluster works in unicast or multicast mode, you need to configure a static MAC address entry mapping multiple outbound interfaces on switches to configure multi-interface ARP. Only the S5720-EI, S5720-HI, S5720I-SI, S5720S-SI, S5720-SI, S5735-S, S5735S-S, S5735-S-I, S5730-HI, S5730S-EI, S5730-SI, S5731-H, S5731-S, S5731S-H, S5731S-S, S5732-H, S6720-EI, S6720-HI, S6720S-EI, S6720S-SI, S6720-SI, S6730-H, S6730S-H, S6730-S, and S6730S-S support multi-interface ARP.

When the NLB cluster works in IGMP multicast mode, the S5720-EI, S6720-EI, and S6720S-EI do not support multi-interface ARP by dynamically learning MAC address entries mapping multiple outbound interfaces.

Procedure

Run system-view
The system view is displayed.
Configure a static MAC address entry mapping multiple outbound interfaces or configure the device to dynamically learn MAC address entries mapping multiple outbound interfaces.

The VLAN specified in the following steps cannot be a MAC VLAN, super VLAN, leased line VLAN, or control VLAN of Smart Ethernet Protection (SEP) and Rapid Ring Protection Protocol (RRPP).
- When the NLB cluster works in unicast or multicast mode, you can use either of the following methods to configure a static MAC address entry mapping multiple outbound interfaces.
  
  If the MAC address entry mapping multiple outbound interfaces is configured for the first time, run commands in the system view. If the MAC address entry mapping multiple outbound interfaces has been created and a certain interface needs to be added or deleted, run commands in the corresponding interface view.
  - Configuring a MAC address entry mapping multiple outbound interfaces in the system view
    
    Run the mac-address multiport mac-address interface { interface-type interface-number1 [ to interface-type interface-number2 ] } &<1-10> vlan vlan-id command to configure the MAC address entry mapping multiple outbound interfaces in the system view.
    
    By default, no MAC address entries on the device map multiple outbound interfaces.
    
    The value of interface-number2 must be greater than that of interface-number1, and interface-number1 and interface-number2 determine an interface range.
    
    On the S5720-EI, S5720-HI, S5730-HI, S5731-H, S5731-S, S5731S-H, S5731S-S, S5732-H, S6720-EI, S6720-HI, S6720S-EI, S6730-H, S6730S-H, S6730-S, and S6730S-S, when the outbound interfaces are Eth-Trunk interfaces, you must run the unknown-unicast load-balance enhanced command to configure the load balancing mode for BUM traffic on the interfaces. Otherwise, the configuration is invalid.
    
    On the S5720I-SI, S5720S-SI, S5720-SI, S5735-S, S5735S-S, S5735-S-I, S5730S-EI, S5730-SI, S6720S-SI, and S6720-SI, when the outbound interfaces are Eth-Trunk interfaces, you must run the load-balance command to configure load balancing based on IP addresses. Otherwise, the configuration is invalid.
  - Configuring a MAC address entry mapping multiple outbound interfaces in the interface view
    1. Run interface interface-type interface-number
      
      The interface view is displayed.
    2. Run mac-address multiport mac-address vlan vlan-id
      
      The MAC address entry mapping multiple outbound interfaces is configured in the interface view.
      
      By default, no MAC address entries on the device map multiple outbound interfaces.
    3. Run quit
      
      Return to the system view.
    Repeat the preceding steps on each outbound interface so that a MAC address in the MAC address table can map multiple outbound interfaces.
- When the NLB cluster works in IGMP multicast mode, you can perform the following operations to configure the device to dynamically learn MAC address entries mapping multiple outbound interfaces.
  1. Run igmp-snooping enable
    
    IGMP snooping is enabled globally.
  2. Run vlan vlan-id
    
    The VLAN view is displayed.
  3. Run l2-multicast forwarding-mode mac
    
    The multicast forwarding mode in the VLAN is set to MAC address-based forwarding.
  4. Run igmp-snooping enable
    
    IGMP snooping is enabled in a VLAN.
  5. Run quit
    
    Return to the system view.
Run arp static ip-address mac-address [ vpn-instance vpn-instance-name ]
The short static ARP entry is configured.

By default, the ARP table is empty and address mappings are obtained using dynamic ARP.

The value of mac-address must be the same as the MAC address in the MAC address entry mapping multiple outbound interfaces.

Verifying the Configuration

Run the display mac-address multiport mac-address vlan vlan-id or display mac-address multiport [ vlan vlan-id ] [ total-number ] command to display the statically configured MAC address entry mapping multiple outbound interfaces (the NLB cluster works in unicast or multicast mode).
Run the display l2-multicast forwarding-table vlan [ vlan-id ] command to display the dynamically learned MAC address entry mapping multiple outbound interfaces (the NLB cluster works in IGMP multicast mode).
Run the display arp static command to verify static ARP entries.