VPI/VCI conversion method and device of automatic teller machine (ATM) multiple service access exchange board

Abstract

The invention discloses a VPI / VCI conversion method and a device of an automatic teller machine (ATM) multiple service access exchange board. The VPI / VCI conversion method and the device of the ATM multiple service access exchange board are achieved based on an FPGA. A first data input / output end of the device is connected with a switching chip. A second data input / output end is connected with a framing chip. A third data input / output end is connected with a CAM. A one-to-one corresponding mapping table of an inner VPI / VCI and an outer VPI / VCI is stored in the CAM. A cell with the outer VPI / VCI is input by the framing chip, is converted into a cell with the corresponding inner VPI / VCI and sent to the switching chip after the mapping table is required. A cell with the inner VPI / VCI is input by the switching chip, is converted into a cell with the corresponding outer VPI / VCI and sent to the frame chip after the mapping table is required. According to the VPI / VCI conversion method and the device of the ATM multiple service access exchange board, with a permissible range of an ATM protocol, a user can freely configure the VPI / VCI so as to solve the problem that use of the VPI / VCI is limited.

Description

technical field [0001] The invention relates to a method and device for VPI / VCI conversion in an ATM multi-service access switch, and belongs to the technical field of ATM switching. Background technique [0002] The ATM multi-service access switch is mainly composed of a switching chip and a framing chip to realize the exchange of ATM cells between each service sub-card and an ATM uplink port. In practical applications, the switch chip has the following restrictions: If the number of logical ports supported by the switch chip is PID, its occupied bit width is NPID, the occupied bit width of VPI is NVPI, and the bit width occupied by VCI is NVCI, then it needs to meet: NPID+NVPI +NVCI=16bit. For example, if the switch chip supports 30 logical ports, 5 bits are required for the port base address, and only 11 bits are left for NVPI+NVCI. It can be seen that the values ​​of the virtual path indicator VPI and virtual channel indicator VCI available for the virtual path connecti...

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Problems solved by technology

[0007] 3) The VPI / VCI is split and mapped so that the external VPI / VCI cannot truly achieve arbitrary configuration

[0008] 4) Only the case of building a VCC is considered, and the case of building a VPC is not considered

[0009] 5) The mapping between internal VPI / VCI and external VPI / VCI of multiple ports is not considered

[0010] 6) It does not take into account that the NPID, NVPI, and NVCI of the switch chip are configurable and changeable

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