The limitations described in this article apply only when multicast cluster
media access control address support is disabled and you are using only one
network interface card in each cluster host.
If you disable multicast support and are only using unicast, you should install a dedicated network
interface card (NIC) to handle cluster traffic to achieve optimum
performance and the full range of networking functionality. Although it is
possible to have a successful cluster installation with only one NIC, there
are two limitations to this approach:
- Computers within the cluster will not be able to communicate among
themselves with any networking protocol, not just TCP/IP. This can be a
special problem if one or more of the clustered servers also act as
primary and backup domain controllers.
- Networking traffic destined to individual servers within the cluster
will generate additional networking overhead for all computers in the
cluster.
These limitations may not be important for many installations. If the
computers within the cluster are only accessed from outside the cluster
(that is, there are no intracluster communications) and noncluster
communications are infrequent (for example, short nightly updates of the
Web server content to individual computers in the cluster), the use of a
single networking card should be sufficient. Also, it is always possible to
test and demo Windows NT Load Balancing Service (WLBS) using a single network card prior to installing
additional cards for operational purposes.
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