Interesting. Some relevant tidbits my story didn't mention:
The yinrih are capable of STL interstellar travel, but because they can't lose consciousness without dying, they can't resort to hypersleep. Instead, they use a technique called metabolic suspension which halts metabolism but uses Science™ to keep the brain and nervous system active. The device that does this is called a suspension capsule (referenced in the story above). The traveler is completely submerged in a fluid matrix called neurogel that acts as a non-invasive brain-computer interface, a liquid ventilation medium (for when your metabolism starts up again but your lungs are still paralyzed), and a shock absorbent.
Since the person is still conscious but their sensory systems don't work, the suspension capsule presents a simulacrum to the traveler in order to keep them from going insane due to lack of sensory input. It also speeds up their subjective time perception to make the trip pass more quickly. The problem with the simulacrum (sim for short) is that the more realistic it is, the more the person is tempted to dissociate, thinking the sim is reality and forgetting their life outside. In order to stave off this madness, Claravian missionaries (the only group to engage in interstellar travel) undertake a rigorous routine of prayer and meditation to keep their minds anchored in reality.
I needn't tell you that the ability to present an arbitrarily realistic simulation to a person is subject to flagrant abuse, and so-called gel-head parlors offer recreational suspension for a price. This abuse prompts Claravian research monasteries to start looking into safer modes of interstellar travel, which is what results in the invention of the mass router.
As for the router itself, there are strict mass and volume limits to what can be sent through the underlay, meaning individual flows are limited to a single person and maybe a small carry-on. Because the mass router is discovered while a team of missionaries is living among humans on Earth, a mass router trunk is able to be established between Sol and Focus immediately. The missionaries construct a working mass router using their ship's fabricator and materials found on Earth.