Hi my question.
I will get the IP address between 224.0.0.0 and 239.255.255.255
range and port number for each cluster. Do I need to need to anything else? I could not understand the concept how they will do the clustering using the IP address and port.

Documents from webMethods:

Discovery Address:
IP address used to identify members of the cache that are to be
used for clustering. This address must be in the range 224.0.0.0
‐ 239.255.255.255. Note that many addresses in this range are
reserved for use by certain organizations. Addresses in the
range 224.0.0.0 through 224.0.0.255 are reserved for the use of
various multicast‐related protocols. For a list of reserved
multicast addresses, refer to
[url]http://www.iana.org/assignments/multicast‐addresses[/url]

The discovery address, in combination with a particular
discovery port (described below), uniquely identifies a
multicast group. For example, all cache members with the
discovery address 224.0.36.1 and discovery port 24601 form
one multicast group.

The caching software allows all the members of the same
multicast group to access the current state of every cached
element in the group.
When defining a cluster, it is recommended that you define
one discovery address/discovery port combination (multicast
group), per cluster.

Discovery Port:
Port used to identify members of the cache that are to be used
for clustering. This number must be an integer. The default is
24601.

The discovery port, in combination with a particular
discovery address (described above), uniquely identifies a
multicast group. For example, all hosts with the discovery
address 224.0.36.1 and discovery port 24601 form one
multicast group.

The multicast IP and port are just one part of IS clustering (it’s not “wM clustering” because there are multiple products under the wM banner and each of them use different clustering techniques). This part is using Oracle Coherence to keep session and other data in memory of each IS instance in sync. This is used instead of the old db/repository based approach (it’s not used for everything–e.g. scheduled tasks are still stored in a DB).

In the document you quoted, there is a link to a wiki that describes Coherence in detail on many topics, including info on multicast.

I have a follow up question on this post.

If we have two cluster sets (4 nodes in each cluster), should we use the same multicast ip/port on each cluster (with a different cluster name) or should we use different multicast ip/port combination on each cluster?

Thanks,
Vikas.

From the original post:

"The discovery address, in combination with a particular
discovery port (described below), uniquely identifies a
multicast group. For example, all cache members with the
discovery address 224.0.36.1 and discovery port 24601 form
one multicast group.

The caching software allows all the members of the same
multicast group to access the current state of every cached
element in the group."

This implies that if you want independent clusters, they need to use different IPs and/or ports.