摘要:
One embodiment of the present invention provides a method for facilitating asymmetric line rates in an Ethernet passive optical network (EPON) which includes a central node and at least one remote node. During operation, the system provides a downstream code-group clock, wherein each cycle thereof corresponds to a code group transmitted from the central node to a remote node. The system also provides an upstream code-group clock, wherein each cycle thereof corresponds to a code group received at the central node from a remote node. In addition, the system provides a multi-point control protocol (MPCP) clock, wherein the frequency ratio of the MPCP clock to the downstream code-group clock is different from the frequency ratio of the MPCP clock to the upstream code-group clock, thereby allowing the downstream transmission to be performed at a faster line rate than the upstream transmission line rate.
摘要:
One embodiment of the present invention provides a system that decrypts downstream data in an Ethernet passive optical network (EPON). During operation, the system receives a data frame which is encrypted based on a remote input block and a session key, wherein the remote input block is constructed based on a remote cipher counter and a remote block counter. The system adjusts a local cipher counter based on a received checksum located in a preamble of the data frame, wherein the local cipher counter is substantially synchronized with the remote cipher counter. In addition, the system truncates the local cipher counter by discarding n least significant bits thereof. The system then constructs a local input block based on the truncated cipher counter and a local block counter for the received data frame. Next, the system decrypts the data frame based on the local input block and the session key.
摘要:
One embodiment of the present invention provides a system that facilitates registration of remote nodes in an Ethernet passive optical network (EPON). The system includes a central node and at least one remote node, wherein a number of virtual remote nodes are coupled to a common physical remote node and transmit upstream data through a common transmitter within the common physical remote node. During an initial discovery cycle, the system receives a solicitation message from the central node at a remote node, wherein the solicitation message assigns a discovery slot in which an unregistered remote node may transmit a response message to the central node for registration. The system then transmits a response message from an unregistered remote node to register within the assigned discovery slot. If multiple virtual remote nodes coupled to the common physical remote node seek registration concurrently, the system controls the transmission of response messages from these virtual remote nodes to the central node so as to avoid collisions between response messages from different remote nodes.
摘要:
A system in an Optical Line Terminal (OLT) to dynamically manage polling rates in a passive optical network is provided herein. The system includes a Media Access Control (MAC) unit that is configured to receive a first message from an Optical Network Unit (ONU). The first message includes a status of an upstream queue of the ONU. The system includes a traffic monitor unit coupled to the MAC unit and is configured to receive the first message from the MAC unit and place the upstream queue of the ONU in an inactive mode if the status of the upstream queue indicates that the upstream queue is empty.
摘要:
One embodiment of the present invention provides a system that facilitates transmission control in an Ethernet passive optical network, which includes a central node and at least one remote node, and wherein a remote node implements a data-link layer and a physical layer. During operation, the system starts by receiving, at the physical layer of a remote node, a word which is communicated from the data-link layer of the remote node, wherein the word may be a data word or an idle word. The system then delays the word for a pre-determined amount of time before allowing the word to be transmitted by a transmitter, thereby providing time for turning the transmitter on or off. The system also turns the transmitter on or off based on the content of the received words.
摘要:
One embodiment of the present invention provides a system that facilitates construction of a forward error correction (FEC) coded Ethernet frame. The system generates a number of FEC parity bits for the conventional Ethernet frame and inserts a start sequence before the conventional Ethernet frame. Next, the system appends an even- or odd-delimiter to the conventional Ethernet frame. The even-delimiter and the odd-delimiter are selected such that there is a sufficiently large Hamming distance between them, thereby reducing the probability of mistaking the even-delimiter for the odd-delimiter, or mistaking the odd-delimiter for the even-delimiter, if bit error occurs.
摘要:
One embodiment of the present invention provides a system that facilitates construction of a forward error correction (FEC) coded Ethernet frame. During operation, the system receives a conventional Ethernet frame. The system then generates a number of FEC parity bits for the conventional Ethernet frame and inserts a start sequence before the conventional Ethernet frame. Next, the system appends an even- or odd-delimiter to the conventional Ethernet frame. The even-delimiter is used to separate the conventional Ethernet frame from the FEC parity bits if the last symbol of the conventional Ethernet frame is in an odd-numbered position. The odd-delimiter is used to separate the conventional Ethernet frame from the FEC parity bits if the last symbol of the conventional Ethernet frame is in an even-numbered position. The even-delimiter and the odd-delimiter are selected such that there is a sufficiently large Hamming distance between them, thereby reducing the probability of mistaking the even-delimiter for the odd-delimiter, or mistaking the odd-delimiter for the even-delimiter, if bit error occurs within the even- or odd-delimiter. The system also appends the number of FEC parity bits to the even- or odd-delimiter and appends a second delimiter to the FEC parity bits.
摘要:
Embodiments of an apparatus including a user network interface configured to receive from a network a packet to be transmitted upstream over a PON are provided herein. The packet is marked with a first category type or a second category type. The apparatus further includes an upstream first in, first out (FIFO) queue configured to store the packet if the packet is marked with the first category type or the second category type.
摘要:
The present disclosure is directed to a method and apparatus for maintaining sub-queues at an ONU and for maintaining a count of an amount of data stored in each sub-queue or a count of an amount of data associated with elements stored in each sub-queue. The sub-queues represent partitions in a first in, first out (FIFO) queue used by the ONU to buffer packets, or elements that are associated with packets, to be sent upstream. The sub-queues are coupled in series such that the output of a first sub-queue feeds the input of a second sub-queue, the output of the second sub-queue feeds the input of a third sub-queue, etc. Each sub-queue has a defined threshold that sets a maximum amount of packet data it can buffer or the elements in which it buffers can be associated with.
摘要:
A system and method for applying an extended multipoint control protocols to wireless access systems. A medium-to-medium adaptor can be provided in an adaptor node that can interface with an upstream optical line terminal in a PON domain and a downstream device in a non-PON wireless domain. The medium-to-medium adaptor enables an implementation of end-to-end services across multiple quality of service (QoS) domains by passing all traffic with controlled delay and without contention.