collision domain
termnetworking
The stretch of shared network in which two devices transmitting at once garble each other: one collision domain, one conversation at a time.
On coaxial Ethernet the whole cable was a single collision domain, and hubs and repeaters only stretched it further: every added station raised the odds that two would speak at once and both would have to back off. Bridges and then switches broke the domain apart, giving each port its own, which is the entire commercial story of Kalpana's 1990 EtherSwitch. Full-duplex links finished the job by removing contention altogether, so on modern switched Ethernet a collision domain is a single cable with one device per end. The concept survives in exams and in the contrast that still matters daily: switches split collision domains, but only routers (or VLANs) split broadcast domains.