1.1目的ISO 21080:2016定义了空间环境中应用的CCSDS利克利德传输协议（LTP）和相关服务的推荐标准。LTP在底层（通常是数据链路）通信服务之上提供可选的可靠性机制。 1.2范围LTP旨在用于空间环境中使用的当前和设想的数据包交付服务，包括: -CCSDS常规分组遥控； -CCSDS常规数据包遥测。 对于空间数据链路，LTP通常将部署在支持CCSDS封装数据包的CCSDS数据链路上，以便一个LTP段可以封装在单个封装数据包中。 LTP还可以在各种地面网络服务上运行，包括CCSDS为交叉支持目的指定的服务。

1.1 Purpose ISO 21080:2016 defines a Recommended Standard for the CCSDS Licklider Transmission Protocol (LTP) and associated service for application in the space environment. LTP provides optional reliability mechanisms on top of an underlying (usually data link) communication service. 1.2 Scope LTP is intended for use over the current and envisaged packet delivery services used in the space environment, including: - CCSDS conventional packet telecommand; - CCSDS conventional packet telemetry. For space data links, LTP will typically be deployed over a CCSDS data link that supports CCSDS Encapsulation Packets so that one LTP segment can be encapsulated in a single Encapsulation Packet. LTP may also operate over a wide variety of ground-network services including those specified by the CCSDS for cross-support purposes.