Intergraph WebScale User Manual page 27

WebScale™ User's Guide
Cluster's Network Address
This parameter specifies the network address ("MAC" address) for the network
interface card (NIC) to be used for handling cluster traffic. WebScale automatically
generates the network address based on the cluster's primary IP address. WebScale
uses a locally administered address, which also is a multicast address if you have
multicast support enabled.
If multicast support is disabled, WebScale automatically will instruct the NIC's driver
(via the registry) to override the NIC's unique, built-in network address whenever
Windows NT is restarted (as long as the WebScale driver remains bound to the NIC; see
the Bindings section). You do not need to manually configure the NIC to recognize
this address. Some NIC's may not allow the built-in network address to be modified. If
you experience this problem, it will be necessary to obtain and install a different NIC
that supports this functionality; please contact Intergraph Computer Systems, Inc. for
more information.
If you have other WebScale clusters on one local subnet, each cluster will need to use a
different network address. When you select a different primary IP address for each
cluster, WebScale automatically ensures that the clusters use unique network addresses.
In rare cases, Intergraph Computer Systems, Inc. may instruct you to override the
network address. If you do so, the network address should be entered as a sequence of
six hexadecimal values separated by dashes (for example, 01-60-97-19-00-ac); be sure
to enter the dashes between the numbers within the address.
Multicast Support
This parameter specifies whether a multicast cluster MAC address should be used for
cluster operations. If this option is enabled, WebScale will convert the cluster network
address into a multicast address if necessary. It will also ensure that the cluster IP
address(es) resolve to this multicast address as part of the ARP protocol. The NIC to
which the WebScale driver is bound will retain its original MAC address.
Note: some routers may not support ARP resolution with multicast addresses. In this
case, enter a static ARP entry into the router's ARP table to resolve the cluster IP
address(es) into the multicast MAC address.
If multicast support is disabled, WebScale will convert the cluster network address into
a non-multicast address if necessary. It also will instruct the NIC's driver (via the
registry) to override the NIC's unique, built-in network address whenever Windows NT
is restarted (as long as the WebScale driver remains bound to the NIC; see the
Bindings section).
This option is enabled by default starting with WebScale Version 2.0.
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