A their critical section. In distributed mutual exclusion,

A distributed system is a model in which components located on networked
computers communicate and coordinate their actions by passing messages1.
Examples of distributed systems are Intranets, Internet, DNS(Domain Name
Server), ATM, Railway Reservation systems etc. The problem of mutual exclusion is
one of the basic problems in distributed systems. Mutual exclusion is a
fundamental issue in the design of distributed systems and an efficient and
robust technique for mutual exclusion is essential to the viable design of
distributed systems. Mutual exclusion makes sure that concurrent process access
shared resource or data in a serialized way. If a process is executing in its
critical section, then no other processes can be executing in their critical
section. In distributed mutual exclusion, processes communicate each other only
via messages. Here we see unpredictable message delays which processes must
expect2. The processes exchange information for getting some conclusion about
the systems and cooperating processes. If messages are not arranged correctly,
the critical section can not be running properly. A distributed mutual
exclusion algorithm is done for entering into the critical section and manages conflicts
when more than one process wants to enter a critical section simultaneously.
The algorithm depends on their characteristics such as message complexity,
types, synchronization delay. The aim of distributed mutual exclusion are
safety, liveness and fairness. One of the main aim is safety where one process
holds the lock at any time. Second aim is liveness where no-one holds the lock
and third aim is fairness where processes are arranged in-order and it has bounded
wait. Other goals of distributed mutual exclusion are to reduce message traffic
and minimize synchronization. The design of distributed mutual exclusion is
complex because these algorithm have to handle changeable message delays and
the partial knowledge of system state2. A common model is generally used for
the majority of mutual exclusion algorithm1. In a distributed algorithm, the
decision must made independently from other nodes in the system and the
decision is the same.