Patent ID: 6973048

Claim:
An apparatus comprising: a) a first add/drop multiplexor comprising: i) a first input for receiving a first signal from a first node, ii) a first output for transmitting a second signal to a second node, iii) a second input for receiving a third signal from a first output of a second add/drop multiplexor, and iv) a second output for transmitting a fourth signal to a first input of said second add/drop multiplexor; and b) said second add/drop multiplexor comprising: i) said first input for receiving said fourth signal from said second output of said first add/drop multiplexor, ii) said first output for transmitting said third signal to said second input of said first add/drop multiplexor, iii) a second input for receiving a fifth signal from said second node, and iv) a second output for transmitting a sixth signal to said first node.