1范围和应用领域本国际标准规定了多链路程序，其中数据链路层的多个并行数据链路用于在网络层实体之间提供可变带宽的数据链路。多链路过程（MLP）作为数据链路层的一个新的上层子层存在，在网络层和数据链路层中的多个单数据链路协议功能（SLP）之间运行（见图1）。本国际标准未规定SLP向MLP指示多链路帧传输已成功完成的方式。 这些多链路程序不排除使用不同的单链路程序，每个程序具有不同的延迟特性和/或线路速度，以形成一个多链路组。当在一个或多个并行数据链路上使用本国际标准定义的程序时，数据链路的两端必须知道，在发送第一个多链路帧之前，将使用这些程序。这可以通过事先约定该数据链路上的所有通信将使用这些程序来实现，或者通过其中一个SLP协商使用这些程序，或者通过其他方式来实现。 本国际标准未定义双方就使用或不使用这些多链接程序达成共识的方法。

1Scope and Field of ApplicationThis International Standard specifies multilink procedures where a multiplicity of parallel data links at the data link layer are used to provide a variable bandwidth data link between network layer entities. The multilink procedures (MLP) exist as a new upper sublayer of the data link layer, operating between the network layer and a multiplicity of single data link protocol functions (SLPs) in the data link layer (see figure 1).This International Standard does not specify the way in which the SLPs indicate to the MLP that the transmission of a multilink frame has successfully been completed.These multilink procedures do not preclude the use of different single link procedures, each with differing delay characteristics and/or line speeds to form one multilink group.When the procedures defined by this International Standard are to be used on one or more parallel data links, both ends of the data link must know that these procedures are to be used before the first multilink frame is sent. This could be achieved by a prior agreement that all communications on this data link will use these procedures, or by one of the SLPs negotiating the use of these procedures, or by some other means. The method by which both ends achieve a common understanding as to the use or non- use of these multilink procedures is not defined in this International Standard.