cliffordgormley
asked on
Using Network Load Balancing in unicast mode
Hi,
Windows Server 2003
Balancing 2 web servers using Network Load Balancing. (NLB) in Unicast Mode.
Hello,
If I load-balance two www servers using NLB in unicast mode, do I need a separate network adaptor on each NLB host to transmit NLB heartbeats between the two hosts?
I know that, in unicast mode, the MAC address associated with each host will be identical, so they will not be able to communicate with each other. Thus I think that I need a separate NIC for heartbeat communication. None of the Windows documentation that I read seemed to explicity state this. In fact, I read that hearbeat communication must occur across the NLB cluster adaptors...how can this happen in unicast mode if all NLB hosts have the same mac address!?
Thanks
Cliff
Windows Server 2003
Balancing 2 web servers using Network Load Balancing. (NLB) in Unicast Mode.
Hello,
If I load-balance two www servers using NLB in unicast mode, do I need a separate network adaptor on each NLB host to transmit NLB heartbeats between the two hosts?
I know that, in unicast mode, the MAC address associated with each host will be identical, so they will not be able to communicate with each other. Thus I think that I need a separate NIC for heartbeat communication. None of the Windows documentation that I read seemed to explicity state this. In fact, I read that hearbeat communication must occur across the NLB cluster adaptors...how can this happen in unicast mode if all NLB hosts have the same mac address!?
Thanks
Cliff
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So I guess the heartbeats are not sent to the Unicast mac address; the heartbeat is sent to a broadcast mac address that all NLB hosts listen to.
Please confirm.
Please confirm.
Yes; check KB232711: "When the Windows NT Load Balancing Service (WLBS) cluster is configured to use a unicast media access control (MAC) address, the heartbeat is sent to the Ethernet broadcast address, FFFFFFFFFFFF."
See the attached link for information on MAC address.
http://technet2.microsoft.com/windowsserver/en/library/aa15cdd3-7ac5-4846-904e-4ff282f8e7f11033.mspx?mfr=true
http://support.microsoft.com/kb/898867