Summary
The Science Data Transfer Protocol (SDTP) is a secure mechanism for transfer of science data using Hypertext Transfer Protocol Secure (HTTPS) between a data provider and a data subscriber. SDTP will replace the Polling with Delivery Record (PDR) protocol as File Transfer Protocol (FTP) and Secure FTP (SFTP) are phased out. The Request for Comments (RFC) document provides a brief introduction, with the full SDTP specification detailed in Section 3 of the Science Data Transfer Protocol (SDTP) Interface Control Document (ICD).
Status
SDTP is an approved NASA Earth Science Data Systems convention.
| ESCO RFC | ESDS-RFC-045 – Science Data Transfer Protocol |
| DOI | https://doi.org/10.5067/DOC/ESCO/ESDS-RFC-045v1 |
| Suggested Citation | Ho, E., & Voorhies, S. (2023). Science Data Transfer Protocol. NASA Earth Science Data and Information System Standards Coordination Office. https//doi.org/10.5067/DOC/ESCO/ESDS-RFC-045v1. |
| Specification | NASA ESDIS Project, Science Data Transfer Protocol Interface Control Document, 423-ICD-027, Original, October 2021 (expires October 2026).
[Copy provided for convenience. The official ICD is managed in the Configuration Management EOSDIS Tool (COMET) system, which requires a NASA login to access.] |
NASA Earth Science Community Recommendations for Use
Strengths
SDTP is a standard interface mechanism developed to comply with NASA security requirements for the exchange of science data between Earth Science Data and Information System (ESDIS) elements. SDTP is intended for use by ESDIS data providers and subscribers that have sustained data flows and currently use the PDR protocol, or expect to establish new sustained data flows. SDTP and PDR will co-exist to enable legacy systems to migrate away from FTP/SFTP and minimize disruptions of existing systems. This secure transfer protocol could also be used for sustained data flows between DAACs and other data providers or subscribers. The Science Data Transfer Protocol Interface Control Document (423-ICD-027) has been approved through COMET and is under ESDIS Project configuration control.
As PDR is phased out, the Cloud Notification Mechanism (CNM) will provide notification of data transfers between on-premises platforms and the Earthdata Cloud, while utilizing SDTP to comply with NASA security requirements.
Weaknesses
SDTP provides a secure transfer protocol for the exchange of science data between providers and subscribers. While this mechanism for transfer of science data works well for collections with routine data flows, it may not be optimal for static datasets with a single delivery or high latency datasets due to the amount of work involved in setting up access to individual topics or subscriptions.
Applicability
SDTP is a common set of commands over HTTPS that meets all of NASA's security requirements for data transfer processes and has been developed to replace the PDR mechanism. SDTP has been used successfully as a standard protocol for exchange of data between ESDIS elements.
Limitations
Interacting with the SDTP Server manually is challenging to new users. This issue should be resolved as additional data flows are established and documentation has been tailored to the users’ specific needs.