Vendor lineage
Bridge Communications - the box between the networks
Built the equipment that joined incompatible networks, then merged with 3Com in 1987.
Bridge Communications made internetworking equipment - the devices that connected local networks to each other and to hosts - in the years when a building could easily contain several networks that had no way to reach one another. It merged with 3Com in 1987, which is what a successful company in this window usually became.
The company's existence is itself evidence for how the internetworking window opened. Nobody needed a product like this until local area networks had succeeded well enough to proliferate, and the proliferation happened department by department rather than by plan.
The 3Com merger also shows the consolidation pattern that followed: the firms that defined the window mostly did not survive it as independent companies, and the ones that bought them are the names still on price lists.