Packet transport layer apparatus

A packet transport layer apparatus comprising:

• an I-component ingress receiving frames having different formats via a single customer network port (CNP), assigning a component identifier (ID) to a received frame according to a format of the received frame, and then outputting an I-tag frame via a virtual output port by encapsulating the received frame with an I-tag;
• a B-component ingress outputting a B-tag frame via provider network port (PNP) by encapsulating, with a B-tag, the I-tag frame received from the I-component ingress via a virtual input port;
• a B-component egress translating a B-tag frame, received via a PNP, into an I-tag frame by removing a B-tag, and then outputting the I-tag frame via a virtual output port;
• and
• an I-component egress removing an I-tag from the I-tag frame received from the B-component egress via a virtual input port, assigning a component ID to the I-tag removed frame according to a format of the I-tag removed frame, translating a format of the I-tag removed frame according to the component ID and a T-component ID, and outputting the format-translated frame via a CNP