H3C Technologies H3C S10500 Series Switches - Manual (Page 17)

6
To do… Use the command… Remarks
Enter system view system-view —
Enable ARP quick update
mac-address station-move
quick-notify enable Optional
Disabled by default.
NOTE:
H3C recommends enabling ARP quick update in WLANs only.
Enabling natural mask support for ARP requests
This feature enables the device to learn the sender IP and MAC addresses in a received ARP request
whose sender IP address is on the same classful network as but a different subnet from the IP address of
the receiving interface. A classful network refers to a class A, B, or C network.
For example, VLAN-interface 10 with IP address 10.10.10.5/24 receives an ARP request from
10.11.11.1/8. Because the subnet address calculated by the AND operation of 10.11.11.1 and the receiving
interface’s 24-bit subnet mask is not in the subnet 10.10.10.5/24, VLAN-interface 10 cannot process the
ARP packet.
With this feature enabled, the device calculates the subnet address by using the default mask of the class
A network where 10.10.10.5/24 resides. Because 10.10.10.5/24 is on the same class A network as
10.11.11.1/8, VLAN-interface 10 can learn the sender IP and MAC addresses in the request.
Follow these steps to enable natural mask support for ARP requests:
To do… Use the command… Remarks
Enter system view system-view —
Enable natural mask support for
ARP requests
naturemask-arp enable
Required
Disabled by default.
Configuring multicast ARP
Microsoft Network Load Balancing (NLB) is a load balancing technology for server clustering developed
on Windows Server.
NLB supports load sharing and redundancy among servers within a cluster. To implement fast failover,
NLB requires that the switch forwards network traffic to all servers or specified servers in the cluster, and
each server filters out unexpected traffic. In a medium or small data center that uses the Windows Server
operating system, the proper cooperation of the switch and NLB is very important.
Microsoft NLB provides the following packet sending modes to make the switch forward network traffic
to all servers or specified servers:
• Unicast mode: NLB assigns each cluster member a common MAC address, which is the cluster
MAC address, and changes the source MAC address of each sent packet. Thus, the switch cannot
add the cluster MAC address to its MAC table. In addition, because the cluster MAC address is
unknown to the switch, packets destined to it are forwarded on all the ports of the switch.
• Multicast mode: NLB uses a multicast MAC address that is a virtual MAC address for network
communication, for example 0300-5e11-1111.