Stopping Unicast port flooding due to Microsoft. Network load Balancing

[ra_jeshkalra_2]

Hi,

I have got two pairs of windows 2000 Advanced server configured in windows network load balancing in the unicast mode.

For each pair of server, the first server is connected to first Cisco 2950 catalyst switch and the second is connected in to second Cisco 2950 catalyst switch.

the same way the second pair is also connected to each of Cisco switches for redundancy.

All the ports of both the switches are in same VLAN.

The NLB is havig a common mac address.Due to the configuration of NLB in unicast mode, excess traffic is being generated on the LAN.

Can somebody suggest if I can create some new VLAN in the Cisco swtches to contain this unicast raffic flooding.

thanks

[miguelangel-fernandez]

Hi " ra jeshkalra";

See this link--> http://www.cisco.com/en/US/partner/products/hw/switches/ps700/products_tech_note09186a00801d0808.shtml

Causes of Flooding

The very cause of flooding is that destination MAC address of the packet is not in the L2 forwarding table of the switch. In this case the packet will be flooded out of all forwarding ports in its VLAN (except the port it was received on). Below case studies display most common reasons for destination MAC address not being known to the switch.

Regards