scheme, only a defined set of members can be in a group. The Group
Membership Service(GMS) will detect members joining or leaving the
group. External members cannot join the group. Each node may obtain the
group member details from a central repository or configuration file.
this scheme, the membership is not predefined. Members can join a group
by specifying the appropriate group name, and also can leave the group.
The GMS will detect new members joining or leaving the group. The group
membership information may be obtained from the GMS.
scheme is also called Well-Known Addressed(WKA) based membership. In
this scheme, there is a set of well known members. We can consider these
members as belonging to a static group. External members can join this
group by notifying one of the well known members. These external members
can then get the current group membership from this well known member.
When new members join the group, the well known members will notify all
other members. When members leave the group, the GMS can detect this