Former systems designer for ISDN networks for NYNEX, Verizon’s precursor in the Nottheast United States, here.
ISDN Basic Rate (2B+D) was a low-rate service deliverable over unconditioned twisted-pair circuits from a Telco Central Office. ISDN Primary Rate (23B+D) was a 1.544 Mbps service deliverable over specially condititioned circuits, similar to the non-channelized T1 circuits of the day. That was 1970s technology, implemented primarily to financial services companies during the 1980s. ISDN is a 40 year old technology.
Gigabit Ethernet (along with 10 Gigabit Ethernet and 100 Gigabit Ethernet) took off as switching technology evolved in the 1990s. As switches became cheap, bandwidth (how many Mbits or Gbits per second to a switch port) became very cheap versus the costs for older technology. Most carriers have phased out ISDN and T1/T3 offerings - they can’t compete economically.
When you purchase “High Speed Internet” from a carrier today, they are leveraging inexpensive Ethernet technologies to provide levels of household bandwidth that were never before affordable. But design caveats still remain: “You want fast, cheap, and guaranteed low latency? Pick two.” And guaranteed low latency, over long distances, is the most expensive choice. You can’t exceed 6/10 the speed of light in a vacuum - which is the speed of light in single mode fiber optic cable. It’s the Laws of Physics that apply.
I’ve talked too long here. But please understand that the Internet, as we are now accustomed to it, is a Scientific Miracle. But latency is the cost of that miracle.
