Traditional telephone switching systems support the concept of "host-remote" operation, whereby lines are terminated by equipment in remote locations that is under the control of a host switch -- but potentially with the ability to operate independently of that switch if the control link is cut. With the emergence of next generation networks, a distributed "softswitch" architecture offers the same ability to reliably deliver services across a wide geographic area with several improvements over the previous generation of equipment. Most important of these are: multiple levels of emergency standalone operation; open interoperability; connectionless trunking in a packet network; distributed PSTN connectivity; and host site redundancy.
