PoS
acronymISP & telecom
Stands for: Packet over SONET/SDH
Packet over SONET - IP straight onto the optical hierarchy in PPP framing, skipping ATM's cell tax. The backbone link of the early-2000s internet core.
PoS (RFC 2615) wraps packets in HDLC-like PPP framing directly inside SONET/SDH payloads, so an OC-48 or OC-192 between two core routers carries IP with almost no overhead and none of ATM's segmentation machinery. Through the 1990s-2000s it was how the big router vendors sold the internet core, and the OC-192 PoS interface was the prestige port of its day. Ethernet at 10G and beyond, cheaper per port and end-to-end, eventually took the role; PoS remains the clean example of removing a layer instead of managing it.
Also known as: pos, packet over sonet, ppp over sonet