Technology is often described in terms of layers, from hardware up to software, in whole comprising a “stack” of abstractions that depend on each other. Each layer is defined by the protocols that operate at that level, with the mechanisms of those protocols reverberating up into all the layers built on top of them. Those protocols become principles that the layers above utterly depend on and cannot function without. Each aspect of computing function – compute, memory, storage, etc – has their own respective stacks which ultimately interoperate to create a functioning device.
In the case of networking, this understanding is made explicit by declaration with the Open Systems Interconnection (OSI) model. This standard establishes the networking stack as being divided into seven layers, the first one dealing with the physical connection between network interfaces and the signals passed between them, for example an ethernet cable carrying an electrical signal between the two ports it’s plugged into, and the seventh layer dealing with application protocols such as used by the Internet and email. The protocols used by the Internet function regardless of whether they are being carried on a copper cable, a fiber optic one, or a wireless signal because to them there is no difference; as long as the lower layers are performing their defined functions properly, any layer above can simply depend on that functionality without caring how it is implemented; it is a principle upon which all above layers rest.
Each layer also has constraints that the protocols must operate within. These constraints are imposed by physical reality and manifest in the form of configurations or parameters that the protocols are tuned with. Like every physical constraint, there is a balance between equal and opposing forces that must be considered before ultimately settling on a result. Despite these limits being imposed by laws of nature, the result that is settled upon fundamentally is an assertion. It is informed by some overall design goals that are trying to be achieved, but in theory the end result could have been any value. These assertions become so critical to the system overall that they become almost inseparable from the protocols they guide. They become an assumption embedded within the protocol itself that is only known by experts who work with that protocol.
At the lowest layer, two assertions made would be the voltage and frequency of the signal being transmitted. A signal could theoretically be transmitted at any voltage or frequency within the bounds of natural law that the material doing the transmitting is subject to, but very specific values are eventually determined based on desired engineering outcomes; they become an assumption inseparable from the protocol itself. At the top layer, the Domain Name System (DNS) assumes that a root zone is available and being run by a root server; if this assumption ever fails, the DNS protocol will fail to resolve hostnames.
Indeed, protocols themselves are nothing more than a set of assertions which define them. Scientifically informed and rigorously defined assertions, but assertions nonetheless. In the case of computers, the collection of all these assertions results in arguably the most powerful tool that humanity has ever built and one of the most wealthy and influential industries in the world. And yet, despite the tremendous complexity of computers themselves and the massive size and influence of the tech industry, it can all be altered by simply changing the assertions which define the technology.