Roman Roads and Internet Protocols
Two networks built two thousand years apart: a short comparison of nodes, standards and resilience.
Translated from the Turkish original: Türkçesini oku
IN SHORT
Roman roads and the internet are two networks built two thousand years apart. Both rest on nodes, links and shared rules. In both, some centres inevitably gain importance even within a distributed structure.
People say “all roads lead to Rome”. The saying is not only a proverb but also the definition of a network. The Roman Empire built tens of thousands of kilometres of roads, and these roads carried military, commercial and administrative traffic. At the birth of the internet there were two ideas: Paul Baran’s design for a distributed network resilient to failures, and ARPANET’s aim of sharing computing resources. Comparing these two networks helps me understand both of them better.
The parts of a network
How can the Roman road network be compared with the internet?
Every network has three basic parts: nodes, links and rules. In Rome the nodes were cities and road stations (mansiones). The links were the roads. The rules were set by the cursus publicus, the state’s official postal and transport system: who could travel, with which document and using which stations was clearly defined. On the internet the nodes are routers, the links are physical lines and the rules are the TCP/IP protocols. Both networks seek an answer to the same question: how can a message be delivered as quickly and reliably as possible?
Shared rules
What shared rules did Roman roads have?
The drainage and layering of Roman roads were largely similar, while their width varied from road to road. Milestones (miliaria) by the roadside gave the distance to the city where the road began or to the nearest town. Just as today’s packet headers carry an address and a timestamp, these shared markers helped travellers understand where they were. Roads built in different periods and regions could be joined to one another, much as devices from different manufacturers can speak the same protocol.
Centre and regions
Was the Roman road network tied to a single centre?
Symbolically, Rome’s road network was tied to Rome, but in practice it consisted of regional networks organised around provincial capitals. Trouble at a single node did not stop the whole system.
The internet has a similar structure. Data packets do not have to pass through a single centre, and when one route is closed another can be found. Even so, some nodes today (undersea cables, the domain name system, large cloud providers) are so important that a failure in them can affect millions of people. The emergence of centres even within a distributed network is a tendency we still meet two thousand years later.
The greatest achievement of infrastructure is to be invisible. For a Roman as for a user today, the network is noticed only when it breaks.
References
- Abbate, J. (1999). Inventing the Internet. MIT Press.
- Baran, P. (1964). On distributed communications networks. IEEE Transactions on Communications Systems, 12(1), 1–9. https://doi.org/10.1109/TCOM.1964.1088883
- Laurence, R. (1999). The roads of Roman Italy: Mobility and cultural change. Routledge. https://doi.org/10.4324/9780203062418
- Leiner, B. M., Cerf, V. G., Clark, D. D., Kahn, R. E., Kleinrock, L., Lynch, D. C., Postel, J., Roberts, L. G., & Wolff, S. (2009). A brief history of the internet. ACM SIGCOMM Computer Communication Review, 39(5), 22–31. https://doi.org/10.1145/1629607.1629613
