The OAIS definition of a SIP is:

Submission Information Package (SIP): An Information Package that is delivered by the Producer to the OAIS for use in the construction or update of one or more AIPs and/or the associated Descriptive Information.

Other relevant OAIS definitions are:

Data: A reinterpretable representation of information in a formalized manner suitable for communication, interpretation, or processing. Examples of data include a sequence of bits, a table of numbers, the characters on a page, the recording of sounds made by a person speaking, or a moon rock specimen.

Data Submission Session: A delivery of media or a single telecommunications session that provides Data to an OAIS. The Data Submission Session format/contents is based on a data model negotiated between the OAIS and the Producer in the Submission Agreement. This data model identifies the logical constructs used by the Producer and how they are represented on each media delivery or in the telecommunication session.

Ingest Functional Entity: The OAIS functional entity that contains the services and functions that accept Submission Information Packages from Producers, prepares Archival Information Packages for storage, and ensures that Archival Information Packages and their supporting Descriptive Information become established within the OAIS.

Submission Agreement: The agreement reached between an OAIS and the Producer that specifies a data model, and any other arrangements needed, for the Data Submission Session. This data model identifies format/contents and the logical constructs used by the Producer and how they are represented on each media delivery or in a telecommunication session.

The discussion of SIPs in OAIS is:

The Submission Information Package (SIP) is that package that is sent to an OAIS by a Producer. Its form and detailed content are typically negotiated between the Producer and the OAIS (see related standards in 1.5). Most SIPs will have some Content Information and some PDI.

The relationships between SIPs and AIPs can be complex; as well as a simple one-to-one relationship in which one SIP produces one AIP, other possibilities include: one AIP being produced from multiple SIPs produced at different times by one Producer or by many Producers; one SIP resulting in a number of AIPs; and many SIPs from one or more sources being unbundled and recombined in different ways to produce many AIPs. Even in the first case, the OAIS may have to perform a number of transformations on the SIP. The Packaging Information will always be present in some form.

APTrust defines SIP as a grouping of files that conforms to the APTrust Bag-It Specification sent by a member to APTrust for preservation. The grouping includes a file manifest; fixity may be audited to ensure no content was corrupted during the transfer. Minimal metadata is required though members may include any additional tag files to capture more metadata.

Bag-It is a standard from the Library of Congress that can be used to transport digital content while assuring the integrity of content through validation of a manifest with checksums in the form of a bag. In a bag, data objects (which may or may not include additional representation information such as descriptive metadata) are stored together in a specified directory called data. Text files (called tag files in the Bag-It spec) are added as sidecar files or documents with the data directory and include a mixture of representation information and Preservation Description Information (PDI).

APTrust is a submission-based repository that accepts format agnostic uploads of digital files to be preserved. Currently, APTrust provides specifications for a lightweight submission package (a Bag) to be created by the owning institution for any content they wish to deposit in APTrust. A Bag consists of generic files alongside a required “tag file” containing technical metadata. The required tag file is read and validated by the bag processing scripts and stored as what APTrust calls an Intellectual Object. Preservation files from valid submission bags are stored as-is in APTrust preservation storage and undergo bit-level preservation.

APTrust uses a robust, redundant cloud-based design to safely store data files deposited to it by Depositors. It is able to return identical data files to the Depositor when requested and provide high-assurance verification of their authenticity.

The workflow for creating an AIP from a SIP is described in Transforming SIPs into AIPs.

OAIS definitions of Content Information and Information Properties as well as discussion of APTrust Content Information and Information Properties can be found in Definition of AIP.

1. CCSDS 650.0-M-2: Reference Model for an Open Archival Information System (OAIS), Recommended Practice, Issue 2. June 2012. (ISO 14721:2012) https://public.ccsds.org/pubs/650x0m2.pdf accessed 2017.07.31
2. Definition of AIP
3. Definition of DIP
4. APTrust Designated Community