State the delivery guarantees with the following techniques in Distrib

1.	State the delivery guarantees with the following techniques in Distributed systems: best effort, at least once, at most once?
Answer» In distributed systems, the following are some common "message delivery approaches": At Most Once: When sending a message from the sender to the receiver via at-most-once message delivery, there is no guarantee that they will receive it. Not all messages will be sent, and if you try to solve the problem yourself by ATTEMPTING delivery at least once or using a different mechanism like batching, you will fail. At Least Once: The at-least-once strategy to sending communications means that either the sender or the recipient of a message must actively participate and ensure that there is no way of knowing if it will be received every time they transmit it. To ensure that each message is sent, either the sender must notice a failure and resend the message, or the receiver must continually REQUEST messages that have not been delivered. The message recipient might be either a sender who continues to send messages until they obtain a response or someone who refuses to give up and KEEPS dragging them in. Exactly Once: With the at-least-once messaging strategy, we can only hope that our processes result in certain messages being delivered several times. Ideally, we'd like to have messages delivered exactly once. However, life isn't always FAIR, and you can't always get what you want!

State the delivery guarantees with the following techniques in Distributed systems: best effort, at least once, at most once?

Answer»

In distributed systems, the following are some common "message delivery approaches":

At Most Once: When sending a message from the sender to the receiver via at-most-once message delivery, there is no guarantee that they will receive it. Not all messages will be sent, and if you try to solve the problem yourself by ATTEMPTING delivery at least once or using a different mechanism like batching, you will fail.
At Least Once: The at-least-once strategy to sending communications means that either the sender or the recipient of a message must actively participate and ensure that there is no way of knowing if it will be received every time they transmit it. To ensure that each message is sent, either the sender must notice a failure and resend the message, or the receiver must continually REQUEST messages that have not been delivered. The message recipient might be either a sender who continues to send messages until they obtain a response or someone who refuses to give up and KEEPS dragging them in.
Exactly Once: With the at-least-once messaging strategy, we can only hope that our processes result in certain messages being delivered several times. Ideally, we'd like to have messages delivered exactly once. However, life isn't always FAIR, and you can't always get what you want!