Load Balancing And Fault Tolerance - Novell NETWARE 6-DOCUMENTATION Manual

Load Balancing and Fault Tolerance

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NetWare TCP/IP Administration Guide
address. If the secondary address is not valid on any of the networks bound to
existing interfaces, the address is rejected and an error message is produced.
With this release, the multihoming feature is extended to help configure the
stack for load balancing and fault tolerance at NIC/Link level. The TCP/IP
stack also provides mechanisms for the administrator to group those NICs
which are similar in characteristics to facilitate load balancing and fault
tolerance across them.
For NetWare 6, TCP/IP has two levels of enabling load balancing and fault
tolerance, one at the system level and another at the local group level. To
benefit from the feature make sure that you have fully enabled it, at both the
levels.
Five types of multihoming configurations are provided:
Single NIC Multiple IP Addresses (Different IP Addresses)—In this type
of multihoming the client to server traffic can be distributed across the routers.
The required level of load balancing can be achieved through static routers and
dynamic DNS. Any dynamic algorithm would take care of the fault tolerance
aspect. In the case of a static route configuration the Multiple Default Gateway
with Dead Gateway Detection support would also help achieve the same
results.
Multiple NIC Multiple IP Address (Different IP Network)—This is a
normal configuration of a router. All the configuration and the advantages
gained by the previous type of multihoming are applicable here also. In
addition, load balancing server-to-client traffic across the NICs and routers is
also possible. This can be achieved with the help of multipath routing.
Multiple NIC Multiple IP Address (Same IP Network)—This type of
multihoming allows for both server-to-client and client-to-server load
balancing and fault tolerance at the Link level. This type of multihoming is
especially helpful in those cases where Route level load balancing and fault
tolerance are not required and become an overhead. Once this type of
multihoming is supported on the server side, the outgoing traffic load is NIC
based on various parameters such as the destination IP address and
interference lead. During NIC failure, the lead is automatically distributed
among the remaining NICs to achieve fault tolerance.