Text of Messaging is an important means of communication between two systems. There are 2 types of...
Messaging is an important means of communication between two systems.
There are 2 types of messaging.- Synchronous messaging.- Asynchronous messaging.
Some observations: Client/Server computing is generally based on a model of synchronous communication:Client and server have to be active at the time of communicationClient issues request and blocks until it receives replyServer essentially waits only for incoming requests, and subsequently processes them
Client cannot do any other work while waiting for replyFailures have to be dealt with immediately (the client is waiting)Connection overhead;Higher probability of failures.
There are two ways to handle failures: 1. Transactional RPC
Enable more complex interactions with some execution guarantees .
2. Service replication and load balancing.
Prevents system from shutting down is service is not available.
MOM stands for message oriented messaging.Asynchronous forms of interaction Communication by exchanging messagesMore dynamicUse of queues acting as buffers.
Both synchronous and asynchronous messaging.Guaranteed message delivery.Heterogeneous platforms.Message priority possible.Broadcast messages.Filtering of messages.
FeatureMOMRPCMetaphorPost-office likeTelephone likeClient/Server time relationshipAsynchronous. Clients and Servers may operate at different times and speedsSynchronous. Clients and Servers must run concurrently. Servers must keep up with clients.Client/Server SequencingNo fixed sequenceServers must first come up before clients can talk to them.StyleQueuedCall-ReturnPartners need to be availableNoYesTransactional SupportYes (Some Products) Message Queue can participate in the commit synchronizationNo. Requires a Transactional RPC.Message FilteringYesNo