[royce]

I work in telco, too - by my read, they're not disagreeing:

  Although Diameter was intended to replace RADIUS, the
  protocol itself offers no security when used over TCP. As a
  result, RFC 6733 suggests that Diameter messages should
  be secured using TLS or DTLS; 5G has replaced Diameter
  with signaling over HTTP/2 [30].

Edit: here's ref [30]: https://mailarchive.ietf.org/arch/msg/radext/Zcuud3GyG221DXn...

"5G completely replaced DIAMETER with signaling over HTTP/2. DIAMETER is only used in legacy systems that has not yet been updated. Early 5G can be deployed as Non-standalone (NSA) or standalone (SA). NSA means a 4G core with 5G radio while SA means both 5G core and 5G radio. NSA has a lot of severe limitations. Many networks are already SA and the rest are working on rolling out SA."