摘要:
A metering device has a first token bucket with a profile, a rate, and a maximum number of tokens. The device has another token bucket with its own profile, two associated rates, and a maximum number of tokens. In operation, the device adds tokens in the first token bucket at its rate if the bucket has less than the maximum number of tokens for that bucket, and adds a number of tokens in the other token bucket at the same rate if the first token bucket is full and the other token bucket is not. Additionally, the device adds tokens in the second token bucket according to the second rate associated with the token bucket if it is not full. When receiving a packet, if the packet has a first marking, and the first token bucket has a sufficient number of tokens, the packet's marking is maintained and the number of tokens in the first bucket is decremented, else, if the packet has one of two markings, and the second token bucket has a sufficient number of tokens, the packet's second marking is selected and the second token bucket is decremented, else, if the packet has a marking other than one of the two markings, the packet's marking is maintained as other than one of the two markings.
摘要:
A translation engine for translating frames of data from one frame format to another frame format in the same manner as an IEEE 802.1D MAC layer transparent bridge as required when transferring frames of data between interconnected heterogeneous local area networks. The translation engine is comprised of a variable length data pipeline capable of maintaining a constant synchronous data stream comprising frames of data from the input to the output of the data pipeline, without introducing any gaps in the data stream caused by removing fields of a frame, or causing the data stream to halt by inserting fields of a frame during translation of a frame from one frame format to another frame format.
摘要:
A translation engine for translating frames of data from one frame format to another frame format in the same manner as an IEEE 802.1D MAC-layer transparent bridge as required when transferring frames of data between interconnected heterogeneous local area networks. The translation engine is comprised of a variable length data pipeline capable of maintaining a constant synchronous data stream comprising frames of data from the input to the output of the data pipeline, without introducing any gaps in the data stream caused by removing fields of a frame, or causing the data stream to halt by inserting fields of a frame during translation of a frame from one frame format to another frame format.
摘要:
A system of and method for communicating control information between two or more entities over one or more backplane connections is described. The control information is stored in a layer of the packet above the physical layer and the packet is then communicated over the one or more backplane connections. A system of and method for performing load balancing over one or more backplane connections is also described. Control information for a packet is mapped into one or more identifiers of one or more of a plurality of backplane connections, and the packet is then communicated over the one or more identified backplane connections. A system of and method for extending the number of ports of a switch is further described. A first switch coupled to a second switch and having a greater number of ports than the second switch is provided. An identifier of a port of the first switch is stored in a layer of the packet above the physical layer. The packet is then communicated between the first and second switches.
摘要:
Information is directed across the same corresponding virtual channels in both a first network switch and a second network switch. As a result, any congestion in the second network switch results only in packet dropping associated with the particular congested virtual channel. However, information continues to move across the remaining uncongested virtual channels. As a result, even if congestion occurs in the second network switch, information continues to flow across the single network link between the first and second network switches, i.e., the single network link is not shut down.
摘要:
A packet switching device having a central shared memory and a number of medium access controllers each coupled to a communications medium to exchange data packets therewith, and a controller coupled to each medium access controller via a data path to exchange data packets with the media access controller. The controller has a number of data path controllers each connected to each medium access controller via a separate and like portion of the data path to exchange a corresponding portion of the data packets with the medium access controller. The data path controllers each have a number of buffers each connected to one of the medium access controllers to which the data path controller is connected, to hold the portion of the data packets exchanged with the corresponding medium access controller. Each data path controller has a selector that selects the buffer from which to transmit or receive the portion of the data packets with the central shared memory and control logic that controls the selector to concurrently select the buffer corresponding to the same medium access controller. A comparison engine associated with each data path controller detects the slice of a field in a data packet buffered in the corresponding data path controller and computes a hashing function on the contents of the slice of the field to generate a hash key. A packet forwarding controller reads one or more entries from a hash bucket in a forwarding database indexed by the hash key and sends the entries to the comparison logic. The comparison logic compares the slice of the field in the buffer to each of the entries and returns the results of the compare to a packet forwarding controller. The forwarding controller then forwards, filters or identifies packets based on the results of the comparisons done on each slice of a field in the packets.
摘要:
A network interconnect device and message exchange protocol for forwarding data among packet forwarding devices are provided. According to one aspect of the present invention, data is forwarded between a first and second packet forwarding device coupled to an interconnect device. The interconnect device receives a menu message from the first packet forwarding device that indicates one or more types of data that are awaiting transmission on the first packet forwarding device. Based upon the menu message, the interconnect device transmits an order message selecting a type of data of the one or more types of data awaiting transmission to the first packet forwarding device. The interconnect device receives a message from the first packet forwarding device containing data of the type selected by the order message. The interconnect device then forwards the data to the second packet forwarding device. According to another aspect of the present invention, data is forwarded among multiple packet forwarding devices through an interconnect device by selecting a configuration of the interconnect device based upon ports to which the packet forwarding devices have data to transfer. For each of the ports of the interconnect device, an indication of ports to which an attached packet forwarding device has data to transfer is received. Based upon these port indications, a configuration of the interconnect device is selected that contains non-conflicting paths through the interconnect device. Data is then forwarded in accordance with the selected configuration by forwarding data from those of the of packet forwarding devices coupled to ports that have been selected as source ports to corresponding destination ports.
摘要:
Systems, mechanisms, apparatuses, and methods are disclosed for forwarding Inter-Switch Connection (ISC) frames in a Network-to-Network Interconnect (NNI) topology, for example, via a network switch which includes a first physical switch port to receive a physical switch link from a second network switch; logic to implement a first logical ISC and a second logical ISC′ connection to the second network switch via the physical switch link; a second physical switch port to receive an interface connection from a third network switch; and switch forwarding logic to forward frames received at the first network switch to the second network switch via the logical ISC or logical ISC′ based on whether or not the physical switch link is part of an active topology upon which the network switch operates or is not part of the active topology upon which the network switch operates. Other embodiments are disclosed.
摘要:
A flexible, policy-based, mechanism for managing, monitoring, and prioritizing traffic within a network and allocating bandwidth to achieve true quality of service (QoS) is provided. According to one aspect of the present invention, a method is provided for managing bandwidth allocation in a network that employs a non-deterministic access protocol, such as an Ethernet network. A packet forwarding device receives information indicative of a set of traffic groups, such as: a MAC address, or IEEE 802.1p priority indicator or 802.1Q frame tag, if the QoS policy is based upon individual station applications; or a physical port if the QoS policy is based purely upon topology. The packet forwarding device additionally receives bandwidth parameters corresponding to the traffic groups. After receiving a packet associated with one of the traffic groups on a first port, the packet forwarding device schedules the packet for transmission from a second port based upon bandwidth parameters corresponding to the traffic group with which the packet is associated. According to another aspect of the present invention, a method is provided for managing bandwidth allocation in a packet forwarding device. The packet forwarding device receives information indicative of a set of traffic groups. The packet forwarding device additionally receives information defining a QoS policy for the traffic groups. After a packet is received by the packet forwarding device, a traffic group with which the packet is associated is identified. Subsequently, rather than relying on an end-to-end signaling protocol for scheduling, the packet is scheduled for transmission based upon the QoS policy for the identified traffic group.
摘要:
A distributed memory switching hub interconnecting heterogeneous local area networks operating at different transmission speeds for receiving, storing and forwarding frames of data. The distributed memory switching hub employs a distributed memory architecture in which memory storage for frames of data received and to be transmitted is located at each low speed LAN port of the distributed memory switching hub. A distributed memory architecture renders unnecessary the need for a central programmable processor or shared common memory to store and forward frames received by the distributed memory switching hub.