摘要:
A network device for processing packets. The network devices includes a ingress module for performing lookups for layer 2 switching and performing operations for maintaining a layer 2 table. When the ingress module updates the layer 2 table, the ingress module records the operation performed on the layer 2 table in a modification buffer. Entries are added to the modification buffer when the layer 2 table is modified and in the order in which the layer 2 table was modified. The network device thus enables reconstruction of the layer 2 table by performing the operations in the modification buffer.
摘要:
A network device for processing packets. The network devices includes a ingress module for performing lookups for layer 2 switching and performing operations for maintaining a layer 2 table. When the ingress module updates the layer 2 table, the ingress module records the operation performed on the layer 2 table in a modification buffer. Entries are added to the modification buffer when the layer 2 table is modified and in the order in which the layer 2 table was modified. The network device thus enables reconstruction of the layer 2 table by performing the operations in the modification buffer.
摘要:
A network device for processing packets. The network device includes an ingress module for performing switching functions on an incoming packet. The network device also includes a memory management unit for storing packets and performing resource checks on each packet and an egress module for performing packet modification and transmitting the packet to an appropriate destination port. Each of the ingress module, memory management unit and egress module includes multiple cycles for processing instructions and each of the ingress module, memory management unit and egress module processes one packet every clock cycle.
摘要:
A network device for processing packets. The network devices includes a ingress module for performing lookups for layer 2 switching and performing operations for maintaining a layer 2 table. When the ingress module updates the layer 2 table, the ingress module records the operation performed on the layer 2 table in a modification buffer. Entries are added to the modification buffer when the layer 2 table is modified and in the order in which the layer 2 table was modified. The network device thus enables reconstruction of the layer 2 table by performing the operations in the modification buffer.
摘要:
A direct memory access (DMA) controller is connected to the CPU bus of a computer system through a bus interface and is also connected to an I/O bus, which is coupled to one or more I/O controllers. Multiple channels, each corresponding to a particular I/O controller, are contained within the DMA controller. The DMA controller controls DMA transfers between the I/O controllers and the main memory of the system and allows multiple transfers to occur concurrently. The DMA controller controls transfers in part through a first arbiter which arbitrates requests for access to the CPU bus coming from the DMA channels and a second arbiter which arbitrates requests for access to the I/O bus coming from the DMA channels and the CPU.
摘要:
A direct memory access (DMA) controller is connected with the CPU bus of a computer system through a bus interface and also to an I/O bus, which is connectable to one or more I/O controllers. The DMA controller contains multiple channels, each corresponding to a particular I/O controller, which are coupled to both the bus interface and the I/O bus. Each of the channels contains at least one register set storing information for the transfer and a data buffer holding the data during a transfer between the I/O bus and the CPU bus.
摘要:
A method and apparatus for controlling data flow across a network performs a method which includes transmitting a packet request message from a first station to a second station, then determining if the packet request message is valid. A request acknowledge message is transmitted from the second station to the first station, and it is then determined if the request acknowledge message is valid. The packet request message and the request acknowledge message each includes a control bit string, an identification bit string, and at least one parity bit.
摘要:
A network switch for switching packets from a source to a destination includes a source port for receiving an incoming packet from a source, a destination port which contains a path to a destination for the packet, and a filter unit for constructing and applying a filter to selected fields of the incoming packet. The filter unit further includes filtering logic for selecting desired fields of the incoming packet and copying selected field information therefrom. The filtering logic also constructs a field value based upon the selected fields, and applies a plurality stored field masks on the field value. The switch additionally includes a rules table which contains a plurality of rules therein. The filtering logic is configured to perform lookups of the rules table in order to determine actions which must be taken based upon the result of a comparison between the field value and the stored filter masks and the rules table lookup.
摘要:
An arbitration scheme for a computer system in which a digital signal processor resides on the computer system's memory bus without requiring a block of dedicated static random access memory. An arbitration cycle is divided into 10 slices of which 5 slices are provided in each arbitration loop to the digital signal processor. Two slices are provided each to the system's I/O interface and to the peripheral bus controller. A final slice is provided to the system's CPU. A default state when no memory bus resource is requesting the system memory bus parks the memory bus on the CPU. The arbitration scheme provides sufficient bandwidth for real-time signal processing by the digital signal processor operating from the system's dynamic random access memory while also providing sufficient bandwidth for a local area network interface through the system's I/O interface.
摘要:
A method and apparatus for controlling data flow across a network performs a method which includes transmitting a packet request message from a first station to a second station, then determining if the packet request message is valid. A request acknowledge message is transmitted from the second station to the first station, and it is then determined if the request acknowledge message is valid. The packet request message and the request acknowledge message each includes a control bit string, an identification bit string, and at least one parity bit.