Passive optical network (PON) system
First Claim
Patent Images
1. A passive optical network (PON) system including:
- a plurality of optical network units (ONUs) accommodating a user terminal, an optical line terminal (OLT) being connected to a wide area network and a passive optical network (PON) which connects between the ONUs and the OLT;
the OLT transferring a downstream frame received from a communication node equipment in the wide area network to the plurality of ONUs via the PON; and
the plurality of ONUs transferring the downstream frame to the user terminal,wherein the downstream frame includes a Layer 2 header and an IP packet,wherein the OLT has a frame analyzing unit that judges whether a downstream frame received from the communication node equipment is a unicast frame or a multicast frame, outputs the downstream frame received from the communication node equipment without conversion when the downstream frame received from the communication node equipment is judged as a unicast frame and removes at least a part of the Layer 2 header information from the downstream frame received from the communication node equipment and outputs the downstream frame whose length is shortened when the downstream frame received from the communication node equipment is judged as a multicast frame; and
a frame generating unit that generates a PON frame by adding a PON-specific header to the downstream frame outputted from the frame analyzing unit, andwherein each of the ONUs has a downstream frame processing unit that extracts a downstream frame from the PON frame received via the PON, and adds a Layer 2 header information generated in said each GNU into the downstream frame when at least said part of the Layer 2 header information is removed.
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Abstract
A PON system capable of utilizing the bandwidth of an optical transmission channel in the PON section. In a PON system including an OLT and a plurality of ONUs, the OLT has: a downstream frame processing unit that removes at least part of the header information in a layer 2 header from a downstream frame received from a wide area network, and converts the remaining frame portion into a frame having a header specific to the PON section; and a downstream frame processing unit that extracts a downstream frame portion to be transferred to a user terminal, from a received frame from a PON, and adds the layer 2 header information deleted in the OLT.
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Citations
9 Claims
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1. A passive optical network (PON) system including:
- a plurality of optical network units (ONUs) accommodating a user terminal, an optical line terminal (OLT) being connected to a wide area network and a passive optical network (PON) which connects between the ONUs and the OLT;
the OLT transferring a downstream frame received from a communication node equipment in the wide area network to the plurality of ONUs via the PON; and
the plurality of ONUs transferring the downstream frame to the user terminal,wherein the downstream frame includes a Layer 2 header and an IP packet, wherein the OLT has a frame analyzing unit that judges whether a downstream frame received from the communication node equipment is a unicast frame or a multicast frame, outputs the downstream frame received from the communication node equipment without conversion when the downstream frame received from the communication node equipment is judged as a unicast frame and removes at least a part of the Layer 2 header information from the downstream frame received from the communication node equipment and outputs the downstream frame whose length is shortened when the downstream frame received from the communication node equipment is judged as a multicast frame; and
a frame generating unit that generates a PON frame by adding a PON-specific header to the downstream frame outputted from the frame analyzing unit, andwherein each of the ONUs has a downstream frame processing unit that extracts a downstream frame from the PON frame received via the PON, and adds a Layer 2 header information generated in said each GNU into the downstream frame when at least said part of the Layer 2 header information is removed. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
- a plurality of optical network units (ONUs) accommodating a user terminal, an optical line terminal (OLT) being connected to a wide area network and a passive optical network (PON) which connects between the ONUs and the OLT;
Specification