ndncatchunks and ndnputchunks are a pair of programs to transfer a file as Data segments.
ndnputchunks is a producer program that reads a file from the standard input, and makes it available as a set of NDN Data segments. It appends version and segment number components to the specified name as needed, according to the NDN naming conventions.
ndncatchunks is a consumer program that fetches Data segments of a file, optionally discovering the latest version of the file, and writes the content of the retrieved file to the standard output.
If a version component is present at the end of the user-specified NDN name, the provided version number will be used, without any version discovery process. Otherwise, discovery Interest(s) will be sent out to fetch metadata of the solicited content from which the Data version will be resolved. For more information about the packet format and naming conventions of Interest and Data packets used for version discovery in ndncatchunks, please refer to: Realtime Data Retrieval (RDR) protocol wiki page
fixed: maintains a fixed-size window of Interests in flight; the window size is configurable via a command line option and defaults to 1.
aimd : adjusts the window size via additive-increase/multiplicative-decrease (AIMD). By default, it uses a Conservative Window Adaptation, that is, the congestion window will be decreased at most once per round-trip-time.
cubic: adjusts the window size similar to the TCP CUBIC algorithm. For details about both aimd and cubic please refer to: A Practical Congestion Control Scheme for Named Data Networking
The default Interest pipeline type is cubic.
The following command will publish the text of the GPL-3 license under the /localhost/demo/gpl3 prefix:
ndnputchunks /localhost/demo/gpl3 < /usr/share/common-licenses/GPL-3
To find the published version you have to start ndnputchunks with the -p command line option, for example:
ndnputchunks -p /localhost/demo/gpl3 < /usr/share/common-licenses/GPL-3
This command will print the published version to standard output.
To publish Data with a specific version, you need to append a version component to the end of the prefix. The version component must follow the aforementioned NDN naming conventions. For example, the following command will publish the version 1449078495094 of the /localhost/demo/gpl3 prefix:
ndnputchunks -Nt /localhost/demo/gpl3/v=1449078495094 < /usr/share/common-licenses/GPL-3
If the specified version component is not valid, ndnputchunks will exit with an error. If no version component is specified, one will be generated and appended to the name.
To retrieve the latest version of a published file, the following command can be used:
ndncatchunks /localhost/demo/gpl3
To fetch a specific version of a published file, you can specify the version number at the end of the name. For example, if the version is known to be 1449078495094, the following command will fetch that exact version of the file (without version discovery):
ndncatchunks -Nt /localhost/demo/gpl3/v=1449078495094
For more information, run the programs with --help as argument.