Addendum

• When a port is added to the VLAN, the port automatically receives traffic if the feature is enabled. Old
ARP entries are not deleted or updated.
• When a member port is deleted, its ARP entries are also deleted from the CAM.
• Port channels in the VLAN also receive traffic.
• There is no impact on the configuration from saving the configuration.
• The feature if enabled is displayed in the show running-config command output that displays ip
vlan-flooding CLI configuration. Apart from it, there is no indication of the enabling of this
capability.
Configuring a Switch for NLB
This functionality is supported on the S4810, S4820T, S6000, Z9000, and MXL platforms.
To enable a switch for unicast NLB mode of functioning, perform the following:
Specify that all the Layer 3 unicast routed data traffic going through a VLAN member port need to be
flooded across all the member ports of that VLAN by entering the ip vlan-flooding command.
There might be some ARP table entries which are resolved through ARP packets which had Ethernet
MAC SA different from MAC information inside the ARP packet. This unicast data traffic flooding
occurs only for those packets which use these ARP entries.
CONFIGURATION mode
ip vlan-flooding
To enable a switch for multicast NLB mode of functioning, perform the following:
1. For multicast mode of NLB, to associate an IP address with a multicast MAC address in the switch,
add a static ARP entry by entering the arp ip-address multicast-mac-address command in
Global configuration mode. This setting causes the multicast MAC address to be mapped to the
cluster IP address for NLB mode of operation of the switch.
INTERFACE mode
arp ip-address multicast-mac-address interface
2. Associate specific MAC or hardware addresses to VLANs.
CONFIGURATION mode
mac-address-table static multicast-mac-address vlan vlan-id output-range
interface
arp (for Multicast MAC Address)
To associate an IP address with a multicast MAC address in the switch when you configure multicast
mode of network load balancing (NLB), use address resolution protocol (ARP).
Syntax
arp ip-address multicast-mac-address interface
To remove an ARP address, use the no arp ip-address command.
Parameters
ip-address Enter an IP address in dotted decimal format.
Microsoft Network Load Balancing
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