资料来源 : Free On-Line Dictionary of Computing

virtual circuit
     
         A {connection-oriented} {network} service which
        is implemented on top of a network which may be either
        connection-oriented or {connectionless} ({packet switching}).
     
        The term "switched virtual circuit" was coined needlessly to
        distinguish an ordinary virtual circuit from a {permanent
        virtual circuit}.  (One of the perpetrators of this confusion
        appears to be ["Networking Essentials", 1996, Microsoft Press,
        ISBN 1-55615-806-8], a book aimed at people preparing for the
        {MCSE} exam on {LANs} and {WANs}).
     
        Not to be confused with {switched virtual connection}.
     
        (2001-10-26)