Abstract: Architecture that facilitates transport high availability for messaging services by providing the ability of a receiving entity (e.g., receiving message transfer agent (MTA)) to detect if a sending entity (e.g., sending MTA or client) is a legacy sending entity. When the receiving entity detects that the sending entity is a legacy system, by advertising transport high availability capability to the sending entity, if the sending entity does not opt-in to this capability, the receiving entity keeps the sending entity client “on hold”, that is, waiting for an acknowledgement (ACK) until the receiving entity delivers the message to the next hops (immediate destinations). This approach maintains at least two copies of the message until the message is successfully delivered (to the next hop(s)). Hence, if the legacy sending entity or the receiving entity fails, the message is still delivered successfully.

Abstract: Architecture that facilitates transport high availability for messaging services by providing the ability of a receiving entity (e.g., receiving message transfer agent (MTA)) to detect if a sending entity (e.g., sending MTA or client) is a legacy sending entity. When the receiving entity detects that the sending entity is a legacy system, by advertising transport high availability capability to the sending entity, if the sending entity does not opt-in to this capability, the receiving entity keeps the sending entity client “on hold”, that is, waiting for an acknowledgement (ACK) until the receiving entity delivers the message to the next hops (immediate destinations). This approach maintains at least two copies of the message until the message is successfully delivered (to the next hop(s)). Hence, if the legacy sending entity or the receiving entity fails, the message is still delivered successfully.

Abstract: Architecture that protects side effect messages by associating the side effect messages with a primary (redundant) message that was received by a transport mechanism (e.g., a message transport agent). Side effect messages are considered “side effects” of a primary message that caused generation of the side effect messages. The primary message is only considered fully delivered after the primary message and all associated side effect messages are delivered, after which the source of the primary message is ACK'd (sent an “ACKnowledgement” message). Hence, in case of hardware failures after the primary message was delivered, but before delivery of side effect messages, the redundancy approach used triggers re-delivery of the primary message and re-generation and delivery of the side effect messages.

Abstract: Architecture for enabling messages to be routed between network servers based on message requirements related to version, capabilities, and features, for example. The message requirements designate delivery over a transport path compatible with the message requirements. The message requirements can include a particular version or other features related to different software applications that require compatibility in message handling. Routing information is maintained related to a transport server or other network transport entity compatible with the message requirements and through which the message can be routed. The message is routed to the compatible transport server for delivery to the destination while avoiding delivery to transport servers incompatible with the message requirements.

Abstract: Architecture that facilitates transport high availability for messaging services by providing the ability of a receiving entity (e.g., receiving message transfer agent (MTA)) to detect if a sending entity (e.g., sending MTA or client) is a legacy sending entity. When the receiving entity detects that the sending entity is a legacy system, by advertising transport high availability capability to the sending entity, if the sending entity does not opt-in to this capability, the receiving entity keeps the sending entity client “on hold”, that is, waiting for an acknowledgement (ACK) until the receiving entity delivers the message to the next hops (immediate destinations). This approach maintains at least two copies of the message until the message is successfully delivered (to the next hop(s)). Hence, if the legacy sending entity or the receiving entity fails, the message is still delivered successfully.

Abstract: Architecture that protects side effect messages by associating the side effect messages with a primary (redundant) message that was received by a transport mechanism (e.g., a message transport agent). Side effect messages are considered “side effects” of a primary message that caused generation of the side effect messages. The primary message is only considered fully delivered after the primary message and all associated side effect messages are delivered, after which the source of the primary message is ACK'd (sent an “ACKnowledgement” message). Hence, in case of hardware failures after the primary message was delivered, but before delivery of side effect messages, the redundancy approach used triggers re-delivery of the primary message and re-generation and delivery of the side effect messages.