'''Ethernet Configuration Testing Protocol''' is a diagnostic protocol included in the Xerox [[Ethernet II]] specification.<ref>{{citation |mode=cs1 |title=Ethernet Specification |sectionchapter=Ethernet Configuration Testing Protocol |publisher=Xerox |quote=Ethernet Configuration Testing Protocol |date=20231986-05-08 |chapter-url=https://www.mit.edu/people/jhawk/ctp.pdf |archive-url-status=livehttps://web.archive.org/web/20201214235416/https://www.mit.edu/people/jhawk/ctp.pdf |accessdatearchive-date=20232020-0912-0914 |url-status=dead}}</ref> Functionality of the protocol is similar to that offered by [[Ping (networking utility)|ping]] but it operates at the [[data link layer]] as opposed to the [[network layer]]. Ethernet Configuration Testing Protocol was implemented on [[Digital Equipment Corporation|DEC]] hosts and [[Cisco Systems|Cisco]] routers.<ref>{{cite web |url=https://aminems.github.io/ctp.html |title=Ethernet configuration testing protocol (CTP) |date=20232016-07-21 |accessdate=20232016-07-21}}</ref>
