2. Massage oriented communication
Introduction
MOM : is an infrastructure that allows that allows communication and
exchange data.
It involves the passing of data between applications using communication
channel that carries self contained units of information
3. Persistent communiaction
Massage submitted for transmission is stored by communication system
for as long it takes to deliver it to receiver
Example ; E-mail, SMS
Not necessary for sender to continue execution after submitting a
massage.
Not necessary for receiver to be excuting at the time submission.
4. Transient communication
Massage is stored by communication system only as long as sending &
receiving are excuting
Example ; transport-level communication services (soter and forward)
Reciever needs to be there when a massage is recieved
5. Asynchronous
Sender continues immediately after it has submitted it’s massage for
transmission
Massage my be in alocal buffer at sending host or at an intermediate
communication server
6. Synchronous
Sender is blocked until it’s massage is stored an a local buffer at receiving
host or actually delivered to receiver
Strongest form; Sender blocked until receiver has processed massage
7. Massage oriented transient communication
Transport-level sockets
Massage passing interface (MPI)
Massage transfer latency milli seconds to seconds
8. Massage oriented persistent communication
Massage queuing system or massage oriented middle ware
Provide intermediate term storage capacity for massages, doesn’t require
either sender or receiver to be active during massages transmission
Massage transfer latency seconds to minutes
9. Massage queuing model
Applications communicate by inserting massages into series of queues
Loosely; coupled communication
Sender is given guarantee that it’s massage will eventually be inserted in
recipient queue
No guarantee on timing, or massage will actually be read
11. Massage queuing interface
Basic interface to a queue in a massage queuing system
primitive Meaning
put Append a massage to a specified
queue.
get Block until the specified queue is
nonempty & remove first massage
poll Check a specified queue for massage &
remove first massage, never block
notify Install a handler to be called when a
massage is put into specified queue
