Multiplexed automatic protection switching channels

A SONET/SDH APS message comprising:

• a first plurality of bits designating one of a first plurality of protection switching nodes of a first ring as a source node during a first ring fault condition;
• a second plurality of bits designating one of said first plurality of protection switching nodes of said first ring as a destination node during said first ring fault condition;
• a third plurality of bits for designating one of a second plurality of protection switching nodes of a second ring as a source node during a second ring fault condition;
• and
• a fourth plurality of bits for designating one of said second plurality of protection switching nodes of said second ring as a destination node during said second ring fault condition, wherein
• (i) said first plurality of bits and said second plurality of bits are located within line overhead bytes of a SONET/SDH frame;
• and
• (ii) said third plurality of bits and said fourth plurality of bits occupy different locations in line overhead bytes of said SONET/SDH frame than do said first plurality of bits and said second plurality of bits.

A SONET/SDH APS message comprising:

• a first plurality of bits identifying one of a plurality of protection switching nodes of a first ring as a first source node for protection switching;
• a second plurality of bits identifying one of said plurality of protection switching nodes of said first ring as a first destination node for protection switching;
• a third plurality of bits identifying one of a second plurality of protection switching nodes of a second ring as a second source node for protection switching;
• and
• a fourth plurality of bits identifying one of said second plurality of protection switching nodes of said second ring as a second destination node for protection switching wherein:
• (i) said first plurality of bits and said second plurality of bits are located within line overhead bytes of a SONET/SDH frame;
• (ii) said third plurality of bits and said fourth plurality of bits occupy different locations in line overhead bytes of said SONET/SDH frame than do said first plurality of bits and said second plurality of bits;
• (iii) said first ring and said second ring are merged with the SONET/SDH frames thereof time-multiplexed into a single SONET/SDH data stream;
• (iv) said first plurality of bits and said second plurality of bits are carried in line overhead bytes of a first SONET/SDH frame of said single SONET/SDH data stream;
• and
• (v) said third plurality of bits and said fourth plurality of bits are carried in line overhead bytes of a second SONET/SDH frame of said single SONET/SDH data stream.

An apparatus for SONET/SDH Automatic Protection Switching comprising:

• a network element of the ring time-multiplexing frames between a slower downstream link to a faster upstream link by terminating the downstream frames and generating upstream frames with corresponding information for sending on the faster link;
• the network element addressing nodes of the ring by four address bits as defined by GR-1230, and by a plurality of extended address bits for automatic protection switching node addresses on the slower downstream link;
• and
• the network element also addressing nodes of the ring by four address bits as defined by GR-1230, and by a plurality of extended address bits for automatic protection switching node addresses on the faster upstream link.