The enterprise wide area network for American Heritage Life, by then part of Allstate: an AT&T frame relay cloud joining Jacksonville to sites in Miami, Austin, Louisville and Concord, New Hampshire, on Cisco 1600, 2500 and 2600 routers.
Point-to-point subinterfaces, with the DLCI, committed information rate and carrier circuit identifier documented per link. A /21 allocated per site, and a separate pair of circuits carrying the interconnect to the parent company.
Scarcity as a design input
Committed rates ran from 32K to 320K. That is the real constraint of the era, and it changes what the job is.
With enough bandwidth, a WAN design is mostly about topology and failure behavior — you do not have to rank the traffic, because everything fits. At 32K committed you cannot avoid ranking it. The design had to decide what mattered, and to be explicit about it, because there was not enough capacity for everything to matter equally and pretending otherwise just moves the decision to whichever application happened to be greedy.
The per-link documentation follows from the same scarcity. When a circuit is a significant line item and its committed rate is a negotiated number, you keep a record of what you are paying for on each one — which is a habit worth carrying forward into eras where bandwidth is cheap and nobody bothers.
Outcome
A documented estate where every link's DLCI, committed rate and carrier circuit identifier was recorded rather than remembered.