Previous step: Requirements

Message Exchange Pattern:

At first we need to define the Message Exchange Patterns used.

Definition:

Legend:

• {Message}: Number of Messages to be send; the elements of a message are: address, payload

• {Confirmation}: Number of Confirmations to be send; elements: address

• {Request}: Number of Requests to be send; elements: address, paylad

• {Response}: Number of Responses to be send; elements: address, payload

Unicast:

• Message: 1

• Confirmation (optional): 1

Multicast:

• Message: 1...n

• Confirmation (optional): 1...n

Single Request Single Response:

• Request: 1

• Response: 1

Single Request Multi Response:

• Request: 1
• Response: 1...n

Multi Request Multi Response:

• Request: 1...n

• Response: 1...m

Architecture:

The architecture of ubermep is shown in the picture below. The transport layer of ubermep is given through the uberlay-projekt.

Protocol:

The structure of the protocol used is the followed:

where * marks the fields that are not communicated if not used.

Explanation:

• id: needed to identify the message
• type: specifies the type of a message
• reliable: specifies if a message is reliable or not
• curr. message: shows the number of the current message, only used for Multi Response - responses
• nr. of message: shows the number of the amount of messages to be send, only used for Multi Response -responses
• payload: the content of a message

Legend: In the following the elements x and - are defined as:

• x := set
• - := not set

Unreliable Unicast:

Unreliable Multicast:

Reliable Unicast:

Reliable Multicast:

Single Request Single Response:

Request:

Response:

Multi Response:

The patterns: Single Request Multi Response and Multi Request Multi Response are combined in one message-type: Multi Response.

Request:

Response:

RPC:

Request:

Response:

Next step: Examples