InterPlaNet

[2] The distance between the planets and their constant motion impose long and variable delay on the communications.

Thus, the traditional protocol stack doesn't function properly.

[3] BP is a standard method of transmitting data using store-and-forward, where data are stored for a period of time at intermediate nodes along a network path, and forwarded to the next station when a link is available.

The intermediate node has two transport protocols, LTP (for data transmission over deep space communication links), and TCP (for transmission over earth communication links).

[4][5] The protocols in the lower layers might change to support the corresponding communication and network.

ICANN meeting, Los Angeles , USA, 2007.
Overview of Bundling Protocol function. An intermediate node's BP turns the bundles from LTP packets into TCP packets.