Networking in-between planets is subjected to various disruptions and delays. As a planet rotates, ground stations will lose communications with spacecrafts or satellites on other planets (such as Mars). Even the Sun itself can block planets as they rotate on different sides on the Sun. Delay/Disruption Tolerant Networking (DTN) is a network that has frequent Disruptions or long Delays in the connection between the network devices. Using a Store and Forward technique, application data is bundled together and stored locally at each node and then forwarded to the next node when access is available.

This is useful for Interplanetary Networking. Therefore communications satellites are useful to relay the data.
How the Interplanetary Internet will work. Interesting details and basics about IPN.

The InterPlanetary Networking Special Interest Group (IPNSIG) has a DTN Tutorial explain how a DTN can be used to form an Interplanetary Internet. The Interplanetary Overlay Network (ION) software distribution is an implementation of Delay-Tolerant Networking (DTN). IOAG Space Internetworking Strategy Group (SISG) & Space Internet Architecture Group (SIAG) has Information on a Recommendation on a Strategy for Space Internetworking and also Operations Concepts for a Solar System Internetwork. Here is an interesting video about the Interplanetary Internet.

Consultative Committee for Space Data Systems (CCSDS) Bundle Protocol Specification: 734.2-R-2

The Delay-Tolerant Networking Research Group (DTNRG) lists various versions of DTN software to use. They also have lots of interesting Documents to read. DTN software is available for Debian and Ubuntu

New NASA Satellite to Boost Space Communications Network.

Deep Space Network and their Wikipedia page.

Mars Exploration Program and MAVEN will help add to the Interplanetary Internet.