http://en.wikipedia.org/wiki/SONET_ring#Network_architectures http://en.wikipedia.org/wiki/SONET_ring#Network_architecture... http://en.wikipedia.org/wiki/Conn

http://en.wikipedia.org/wiki/SONET_ring#Network_architectures http://en.wikipedia.org/wiki/SONET_ring#Network_architecture... http://en.wikipedia.org/wiki/Connectionless_communication http://en.wikipedia.org/wiki/Connectionless_communication