Intergraph WebScale User Manual page 71

WebScale™
WebScale. If you are using a single NIC for both the dedicated and cluster IP
addresses, go on to the next step.
2. If you are using unicast support, the cluster NIC could not change its network
address. This problem only occurs when using a unicast network address (instead
of a multicast address). You should either switch to a different cluster adapter
card or use WebScale's multicast support.
3. The outside network is not reachable. If the system resides on an outside
network, please also see the previous problem.
Problem: Another cluster host unreachable from a cluster host
Description: When I ping a cluster host's dedicated IP address from another cluster
host, I get no response.
Probable cause(s) and resolution:
1. This is a single NIC card limitation. If you are using a single NIC and have not
selected WebScale's multicast support, the cluster hosts will not be able to
communicate with each other even though they can exchange network traffic
with outside systems. Check that you have selected multicast support in the
WebScale Setup dialog to eliminate this problem. If you use multiple NIC's, the
problem should not arise.
Problem: Erratic network behavior
Description: The network behaves in a strange and unpredictable manner. Traffic may
alternate unexpectedly between the cluster hosts.
Probable cause(s) and resolution:
1. Unicast network addresses are confusing a switch. If you are using a switch to
interconnect the cluster hosts, you must use WebScale's multicast support.
Otherwise, the switch is likely to behave erratically when the same unicast
network is used on multiple switch ports. Check that you have selected multicast
support in the WebScale Setup dialog. If you do not want to use multicast
support, you can interconnect the cluster hosts with a hub or coaxial cable instead
of a switch.
Problem: Telnet, etc. to outside system fails.
Description: When I telnet to or browse a system outside the cluster from a cluster host,
I get no response. I can ping the outside system.
Probable cause(s) and resolution:
1. The TCP/IP configuration is incorrect. If you are using a single NIC, the
dedicated IP address must be entered before the cluster IP address(es) in the
TCP/IP configuration within the Windows NT Network dialog. Otherwise, the
cluster IP address may be selected as the source address, and the outside system
will respond to the cluster IP address instead of to the dedicated IP address. In
this case, responses will be directed only to the default host. (Note that you
won't observe this problem on the default host.) Check the TCP/IP configuration
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User's Guide