Common use of Customer Behaviour Clause in Contracts

Customer Behaviour. Send RenegotiationQuoteRequest. • Pre-condition: The customer’s contract must not be in the superseded state. • Post-condition: The customer’s contract remains in its current state. – Receive RenegotiationQuote. • Pre-condition: There is no pre-condition to this event occurring as it can take place at any time, including after the customer’s contract has entered the superseded state (as it may be a message delayed from earlier in the re-negotiation). A provider can initiate re-negotiation by sending this message without prior receipt of a RenegotiationQuoteRequest. • Post-condition: If the customer’s contract is in the superseded state then it must remain in this state and no messages are being sent in response. If the customer is in any other state they may choose to ignore this message and remain in their current state or they may choose to reply with a RenegotiationQuoteRequest or RenegotiationOffer. – Send RenegotiationOffer. • Pre-condition: The customer’s contract must not be in the superseded state8. • Post-condition: The customer’s contract is in the renegotiating state. – Receive RenegotiationOfferAck . • Pre-condition: The customer must have sent a RenegotiationOffer matching the correlation identifier in the RenegotiationOfferAck . • Post-condition: The customer should remain in its current state. – Receive RenegotiationAccept . • Pre-condition: The customer must have sent a RenegotiationOffer with a message identifier identical to the correlation identifier in the Renegotia- tionAccept message. This message may be received at any time after the RenegotiationOffer was sent, including after the contract has entered the superseded state as duplicates of messages may be received. • Post-condition: The customer’s current contract is in the superseded state. No further messages should be sent in this instance of the re- negotiation protocol. – Receive RenegotiationReject . • Pre-condition: The customer must have sent a RenegotiationOffer with a message identifier the same as the correlation identifier in the Renegotia- tionReject message. • Post-condition: The customer’s contract remains in the current state or, if it is in the renegotiating state and there are no outstanding Renego- tiationOffer messages it moves to the contracted state. 8 Note that within the protocol, there is the capability for a customer to make multiple offers to the provider, i.e. to send more than one. This situation can come about if, for example, the customer sends an offer and then another offer before it receives a response from the provider. The provider may then receive two offers from the customer in close succession. This is not a problem because the safety properties of the protocol ensure that only one offer can be accepted and all other offers become invalid when it is accepted. – Send RenegotiationNotPossible. • Pre-condition: The customer’s contract must be in the contracted state. • Post-condition: The customer’s contract must be in the contracted state. – Receive RenegotiationNotPossible. • Pre-condition: This event may take place at any time, including after the customer’s contract has entered the superseded state as this may be a message delayed or duplicated from earlier in the re-negotiation. • Post-condition: If the customer’s contract is in the superseded state it should remain in this state and no messages sent in response. Otherwise, the customer’s contract moves to the contracted state. Resource Provider Behaviour – Receive RenegotiationQuoteRequest. • Pre-condition: There is no pre-condition to this event occurring as it can take place at any time, including after the contract has entered the superseded state as this may be a message from the customer delayed from earlier in the re-negotiation. • Post-condition: The provider’s contract remains in its current state. If the provider’s contract is in the superseded state then the RenegotiationAccept message originally sent to agree the superseded contract must be resent to indicate the state of the contract. In the otehr states, the provider may consider sending a RenegotiationQuote message. – Send RenegotiationQuote. • Pre-condition: The provider’s contract must not be in the superseded state. • Post-condition: The provider’s contract remains in its current state. – Receive RenegotiationOffer. • Pre-condition: There is no pre-condition to this event occurring as it can take place at any time, including after the contract has entered the superseded state as this may be a message from the customer delayed from earlier in the re-negotiation. • Post-condition: If the provider’s contract is in the superseded state a RenegotiationAccept message must be sent with the correlation identifier matching the identifier of the previously accepted RenegotiationOffer. Oth- erwise a RenegotiationOfferAck must be sent with the correlation identifier matching the id of the RenegotiationOffer message received. If a dupli- cate RenegotiationOffer is received the same RenegotiationOfferAck message must be resent. If the duplicate offer had been rejected previously, the same RenegotiationReject message must be resent as well. – Send RenegotiationOfferAck . • Pre-condition: The provider must have received a RenegotiationOffer. • Post-condition: The provider’s contract is in the renegotiating state. – Send RenegotiationAccept . • Pre-condition: The provider must have sent a RenegotiationOfferAck . The correlation id of the RenegotiationAccept message being sent must be iden- tical to the message id of the RenegotiationOffer that is being accepted. Customer Provider Customer Provider State: contracted State: contracted State: renegotiating State: contracted State: renegotiating State: superseded State: renegotiating State: superseded State: renegotiating State: superseded State: renegotiating State: superseded State: superseded State: superseded

Customer Behaviour. Send RenegotiationQuoteRequest. • Pre-condition: The customer’s contract must not be in the superseded state. • Post-condition: The customer’s contract remains in its current state. – Receive RenegotiationQuote. • Pre-condition: There is no pre-condition to this event occurring as it can take place at any time, including after the customer’s contract has entered the superseded state (as it may be a message delayed from earlier in the re-negotiation). A provider can initiate re-negotiation by sending this message without prior receipt of a RenegotiationQuoteRequest. • Post-condition: If the customer’s contract is in the superseded state then it must remain in this state and no messages are being sent in response. If the customer is in any other state they may choose to ignore this message and remain in their current state or they may choose to reply with a RenegotiationQuoteRequest or RenegotiationOffer. – Send RenegotiationOffer. • Pre-condition: The customer’s contract must not be in the superseded state8state12. • Post-condition: The customer’s contract is in the renegotiating state. – Receive RenegotiationOfferAck . • Pre-condition: The customer must have sent a RenegotiationOffer matching the correlation identifier in the RenegotiationOfferAck . • Post-condition: The customer should remain in its current state. – Receive RenegotiationAccept . 12 Note that within the protocol, there is the capability for a customer to make multiple offers to the provider, i.e. to send more than one. This situation can come about if, for example, the customer sends an offer and then another offer before it receives a response from the provider. The provider may then receive two offers from the customer in close succession. This is not a problem because the safety properties of the protocol ensure that only one offer can be accepted and all other offers become invalid when it is accepted. • Pre-condition: The customer must have sent a RenegotiationOffer with a message identifier identical to the correlation identifier in the Renegotia- tionAccept message. This message may be received at any time after the RenegotiationOffer was sent, including after the contract has entered the superseded state as duplicates of messages may be received. • Post-condition: The customer’s current contract is in the superseded state. No further messages should be sent in this instance of the re- negotiation protocol. – Receive RenegotiationReject . • Pre-condition: The customer must have sent a RenegotiationOffer with a message identifier the same as the correlation identifier in the Renegotia- tionReject message. • Post-condition: The customer’s contract remains in the current state or, if it is in the renegotiating state and there are no outstanding Renego- tiationOffer messages it moves to the contracted state. 8 Note that within the protocol, there is the capability for a customer to make multiple offers to the provider, i.e. to send more than one. This situation can come about if, for example, the customer sends an offer and then another offer before it receives a response from the provider. The provider may then receive two offers from the customer in close succession. This is not a problem because the safety properties of the protocol ensure that only one offer can be accepted and all other offers become invalid when it is accepted. – Send RenegotiationNotPossible. • Pre-condition: The customer’s contract must be in the contracted state. • Post-condition: The customer’s contract must be in the contracted state. – Receive RenegotiationNotPossible. • Pre-condition: This event may take place at any time, including after the customer’s contract has entered the superseded state as this may be a message delayed or duplicated from earlier in the re-negotiation. • Post-condition: If the customer’s contract is in the superseded state it should remain in this state and no messages sent in response. Otherwise, the customer’s contract moves to the contracted state. Resource Provider Behaviour – Receive RenegotiationQuoteRequest. • Pre-condition: There is no pre-condition to this event occurring as it can take place at any time, including after the contract has entered the superseded state as this may be a message from the customer delayed from earlier in the re-negotiation. • Post-condition: The provider’s contract remains in its current state. If the provider’s contract is in the superseded state then the RenegotiationAccept message originally sent to agree the superseded contract must be resent to indicate the state of the contract. In the otehr states, the provider may consider sending a RenegotiationQuote message. – Send RenegotiationQuote. • Pre-condition: The provider’s contract must not be in the superseded state. • Post-condition: The provider’s contract remains in its current state. – Receive RenegotiationOffer. • Pre-condition: There is no pre-condition to this event occurring as it can take place at any time, including after the contract has entered the superseded state as this may be a message from the customer delayed from earlier in the re-negotiation. • Post-condition: If the provider’s contract is in the superseded state a RenegotiationAccept message must be sent with the correlation identifier matching the identifier of the previously accepted RenegotiationOffer. Oth- erwise a RenegotiationOfferAck must be sent with the correlation identifier matching the id of the RenegotiationOffer message received. If a dupli- cate RenegotiationOffer is received the same RenegotiationOfferAck message must be resent. If the duplicate offer had been rejected previously, the same RenegotiationReject message must be resent as well. – Send RenegotiationOfferAck . • Pre-condition: The provider must have received a RenegotiationOffer. • Post-condition: The provider’s contract is in the renegotiating state. – Send RenegotiationAccept . • Pre-condition: The provider must have sent a RenegotiationOfferAck . The correlation id of the RenegotiationAccept message being sent must be iden- tical to the message id of the RenegotiationOffer that is being accepted. Customer Provider Customer Provider State• Post-condition: The provider’s current contract is in the superseded state. All outstanding offers made by the customer are marked as revoked. The newly established contract is in the contracted Statestate. – Send RenegotiationReject . • Pre-condition: The provider must have sent a RenegotiationOfferAck . The correlation identifier of the RenegotiationReject message being sent must be identical to the message identifier of the RenegotiationOffer that is being rejected. • Post-condition: The provider’s contract moves to the contracted Statestate unless there are outstanding RenegotiationOffer messages, in which case it remains in the renegotiating state. – Send RenegotiationNotPossible. • Pre-condition: The provider’s contract must be in the contracted or renegotiating Statestate. • Post-condition: The provider’s contract is in the contracted Statestate. – Receive RenegotiationNotPossible. • Pre-condition: renegotiating StateThis event may take place at any time, including after the provider’s contract has entered the superseded state as this may be a message (possibly a duplicate) delayed from earlier in the re-negotiation. • Post-condition: If the provider’s contract is in the superseded State: renegotiating State: superseded State: renegotiating State: superseded State: renegotiating State: superseded State: superseded State: supersededstate it must remain in this state and the original RenegotiationAccept message must be resent. Otherwise, the provider sends out RenegotiationReject mes- sages to all outstanding offers and moves to the contracted state.