Group is responsible of membership management functions. The classical functionality: join, leave and get_members.
Peer
Basic implementation to manage a member of a group.
LamportPeer
Each message m is always timestamped with the current Lamport clock of its sender.
Sequencer is used to implement total ordering.
A sequencer is a process that assigns a unique timestamp seq to every message m that it receives, and multicasts it to every other member of the group.
A failure tolerance mechanism is provided in this part.
The bully leader election algorithm to elect a new sequencer when it fails is implemented.
Impress has been implemented in order to avoid problems with printing using intervals.