Overview#Challenged Networks is defined in RFC 7228 as a network that has serious trouble maintaining what an application would today expect of the end-to-end Internet Protocol model, e.g., by:
- not being able to offer end-to-end Internet Protocol (IP) connectivity at all,
- exhibiting serious interruptions in end-to-end IP connectivity
- exhibiting delay well beyond the Maximum Segment Lifetime (MSL) defined by Transmission Control Protocol (TCP) RFC 0793.
Challenged Networks are Constrained Networks in some sense, but not all Constrained Networks are Challenged Networks. There is no well-defined boundary between the two, though. Delay-Tolerant Networking (DTN) has been designed to cope with Challenged Networks RFC 4838.