High Availability

  • Article

Applies To: Windows Server 2003 with SP1

  • Network Adapters and adapter teaming: Most vendors today offer redundant or fault tolerant adapters i.e. adapter teaming or adapter fault tolerance (AFT). These are supported with NLB, however refer to KB article 278431 for more information.

  • Fault Tolerant/Load balancing Switches: Redundancy at the switch layer can easily be provided by striping the NLB cluster hosts across multiple switches and inter-connecting all the switches that contain a single NLB cluster. Additionally, to prevent switch flooding, only the ports connected to the Primary IP address (where all inbound traffic is sent) can be made hosts of a single VLAN.

  • Fault tolerant Routers: Redundant routers are the most easily overcome using a VRP (virtual router protocol) or HSRP (hot router standby protocol). This allows the router to map the cluster's primary IP address and other multi-homed addresses to the corresponding media access control address. If your router does not meet this requirement, you can create a static ARP entry in the router or you can use Network Load balancing in its default unicast mode.

  • Multiple network interface controllers in cluster nodes

    Windows 2000:

    • If you have two network interface controllers on different subnets then the network interface controller to which NLB is bound should have default gateway and the routing tables need to be reconfigured to make all traffic go through the NLB network interface controller. Default gateway setting on the other network interface controller should be blank.

    • If you have two network interface controllers on the same subnet you will need to configure the network interface controller to which NLB is bound with the default gateway. The other network interface controller should not have a default gateway configured. No need to hack routing tables.

    • Recommendation is to use one network interface controller in each node unless there is a business need for two network interface controllers

    Windows Server 2003

    • If you have two network interface controllers on different subnets you can choose to bind NLB to either or both network interface controllers without any issues. All traffic will go through the correct network interface controller (subnet)

    • If you have two network interface controllers on the same subnet traffic will be routed accordingly.