Spread 서비스 타입	정렬	신뢰성
UNRELIABLE_MESS	안함	비신뢰적임
RELIABLE_MESS	안함	신뢰적임
FIFO_MESS	Fifo by Sender	신뢰적임
CAUSAL_MESS	Causal (Lamport)	신뢰적임
AGREED_MESS	Total Order (Consistent w/Causal)	신뢰적임
SAFE_MESS	Total Order	안전함

Spread에 정의된 정렬 보장 옵션은 다음과 같습니다

안함	정렬 보장을 하지 않습니다. 또한 "None" 정렬 옵션으로 전송된 다른 어떤 메세지는 지금 보낸 메세지보다 이전 또는 이후에 도착할 수 있습니다. 보다 엄격한 정렬 옵션을 가진 메세지들은 이 메세지에 의존할 수도 있습니다. 예를 들어, 만약 FIFO_MESS 메세지 M1이 RELIABLE_MESS 메세지 M2 다음에 전송되었다면 M1은 No ordering guarantee. Any other message also sent with ordering "None" can arrive either before or after this one. Messages with stricter ordering CAN depend on this message. For example, if a FIFO MESS message Ma follows RELIABLE MESS message Mb then Ma cannot be delivered until Ma has been delivered (but the reverse is not true).
Fifo by Sender	All messages sent by this sender(A sender is defined as a particular connection to a Spread daemon, so an application with 3 connections will be considered 3 different senders) of at least Fifo ordering are delivered in FIFO order. As mentioned above a RELIABLE MESS sent after a Fifo message may be delivered before the Fifo message.
Causal (Lamport)	All messages sent by all senders are delivered in an order consistent with Lamport’s definition of "Causal" order. This order is consistent with Fifo ordering.
Total Order (Consistent w/Causal)	All messages sent by all senders are delivered in the exact same order to all recipients. This order is also consistent with Causal order. It is provided by making the partial order defined by causal into a total order. The total order uses the id of the sender to break ties.

It is important to note that messages sent with Fifo ordering or less do not support the full membership semantics of Spread. This is a result of Spread optimizing two common operations, group joins and leaves and sending FIFO or Reliable messages. First, joins and leaves of group members do not cost more then sending one SAFE message and result in no extra synchronization costs. Second, Fifo and Reliable messages are not delayed before delivery by any other messages. So even if gaps exist in the global order of all messages, Reliable messages can still be delivered and Fifo messages can be delivered as long as all the messages from their sender have arrived. Because of these two optimizations, it is possible for a Reliable or Fifo message to be delivered earlier then it would be if it was globally ordered, however a gap in the global sequence may contain a join or leave message (since they are just SAFE messages) so it might be that one process delivers the Fifo or Reliable message before the join and a different process delivers the join first and then the message.

Spread에 정의된 신뢰성 보장 옵션은 다음과 같습니다

비신뢰적임	메세지는 비신뢰적인 방법으로 전송됩니다. 메세지를 잃거나 취소될 수 있으며, Spread에 의해서 복구되지 않습니다.
신뢰적임	메세지는 전송될 그룹의 맴버들인 모든 수령자들에게 신뢰적으로 배달됩니다. Spread는 어떠한 네트워크 손실이 발생해도 메세지를 복구합니다.
안전함	The message will ONLY be delivered to a recipient if the daemon that recipient is connected to knows that all Spread daemons have the message. If a membership change occurs, and as a result the daemon cannot determine whether all daemons in the old membership have the message, then the daemon will deliver the Safe message after a TRANSITIONAL MEMBERSHIP message.