The Internet Society’s Interplanetary Networking Special Interest Group (IPNSIG) has called for the development of “a common, interoperable, autonomous and scalable routing framework within the Solar System Internet.”
The SIG’s call was revealed in its September newsletter , which detailed a late meeting of the body’s Architecture and Governance Working Group that considered current approaches to routing data traffic in space and sought to produce a recommendation toward realizing a common interplanetary network architecture.
That recommendation has now been issued and outlines four principles the Group believes are necessary for a routing framework that can serve the solar system, namely:
- The overall goal is to populate forwarding tables or routing tables (where appropriate) without human intervention and depart from the Earth-centric management scheme
- To enable Autonomy we need a common and standardized way of the following:
- The population of a Forwarding and (where routes are computed) Routing Table
- Function enabling the bundle protocol agent to access a forwarding table API that answers the question: “where should I send this bundle and with what CLA/address?”, similar to ARP lookup Interoperability
- Define a common to every Node set of functions
- Inter-regional routing should be based on a common standard
- Intra-regional routing could be heterogeneous, adopting methods that suit the needs of a specific environment or a mission
- Inter- and Intra-region routing should be interoperable
- Architecture needs to be structured in some way (Hierarchy)
- Node IDs, Addressing Schemes, and segmenting concepts need to be further explored to accommodate the scale of the SSI
The IPNSIG has already developed a technology called “Delay-Tolerant Networking” (DTN) that addresses the issue of latency. DTN tries to address the fact that in space, long distances or network nodes disappearing behind a planet create latency and other conditions that don’t often trouble terrestrial networks. DTN therefore adds some store-and-forward tech, so that packets aren’t dropped for lack of a node to contact.
The SIG’s meeting considered more internetworking ideas to advance DTN, assessing their ability to prioritise high value data, efficiency, and ability to scale to 100,000 nodes.
Candidates are detailed in this summary report from the August meeting. Among the schemes considered was one called “Spray & Wait” that assumes nodes have no knowledge of the network, but in which nodes figure out the optimal number of copies of data that can be in transit. When traffic reaches a node, it is forwarded, and eventually the network figures out how many copies are bouncing around and stops routing any other than those already en route to the destination node.
Spray and Wait was one of five approaches that reached IPNSIG’s stated goal of scaling to 100,000 nodes but did not meet other criteria.
While the SIG has called for work to begin on the routing framework, just who will do the work, select the relevant techs, or decide a development process remains unresolved. ®