摘要:
One embodiment of the present invention provides a system that facilitates forwarding of packets in an Ethernet passive optical network (EPON), which includes a central node and at least one remote node. During operation, the system assigns a logical link identifier (LLID) to a remote node, wherein an LLID corresponds to a logical link between the central node and a remote node. The system also associates an LLID with a port of a switch within the central node, wherein the switch has a number of ports; wherein a port may be a physical port or a virtual port; and wherein the number of ports on the switch are divided into network-side ports and user-side ports. Upon receiving a downstream packet from a network-side port, the system searches a mapping table to determine whether one or more field values of the downstream packet correspond to any LLIDs or ports. If the one or more field values correspond to an LLID, the system assigns the LLID to the downstream packet and transmits the downstream packet to a remote node.
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:
One embodiment of the present invention provides a system for forwarding packets in an Ethernet passive optical network (EPON) which includes a central node and at least one remote node. During operation, the system associates a logical link identifier (LLID) to a logical link between the central node and a remote node, wherein the logical link corresponds to a priority level based on a certain service level agreement (SLA). After receiving a packet to be forwarded to a remote node, the system then determines the value of one or more fields within the packet which is used to indicate a priority level for the packet. Subsequently, the system assigns an LLID to the packet based on the value of the one or more fields, thereby facilitating differentiated service qualities within the EPON.
摘要:
Method and apparatus are provided for reducing vibration in bearings. There are provided first and second bearing rings with races, rotating members rollingly engaging both first and second bearing races, a cage for aligning the rotating members between the first and second bearing races, and vibration reduction means coupled to the cage. The vibration reduction means preferably comprises one or more resonant spring-mass combinations mounted in or on the cage. Damping means is preferably included with the resonant spring-mass combinations. The resonant frequencies of the unmodified bearing cage are first determined and then the spring-mass combinations tuned so that the spring-mass combinations when attached to the cage absorb vibrational energy that would otherwise excite cage vibrations. By selecting the type of spring-mass combination different vibrational modes can be suppressed and/or controlled.
摘要:
The adaptive computing system disclosed herein employs a data structure involving a multiplicity of classifiers, each of which includes a match string of characters which the system attempts to match up with messages generated either by the environment or by other classifiers. Associated with each match string is a response message definer or action part which defines the response to be given when a match is obtained. To facilitate matching in a noisy or changing environment, there is associated with each character in the match string a weighting value and the degree of match is judged by means of a score value which is a function of the weighting values of the characters which match between the match string and the message.
摘要:
One embodiment of the present invention provides a system that facilitates bandwidth-efficient multicast in EPONs. The system includes a central node and at least one remote node. Downstream data from the central node is broadcast through a passive optical coupler to remote nodes. In the other direction, upstream data from a remote node is transmitted through the passive optical coupler to the central node in a unicast manner. During operation, the system first selects a common multicast LLID to represent a number of remote nodes that comprise a multicast group. Upon receiving a multicast message destined to the multicast group, the system sends the multicast message along with the multicast LLID for the multicast group, whereby the multicast message is broadcast through the passive optical coupler in the downstream direction. This allows each remote node belonging to the multicast group to receive the multicast message by matching the multicast LLID.