Method and device for vpi/vci conversion in atm multi-service access switch

Abstract

The invention discloses a method and device for VPI / VCI conversion in an ATM multi-service access switch, which is implemented based on FPGA, the first data input / output end is connected to the switching chip, and the second data input / output end is connected to the framing chip , the third data input / output end is connected to the CAM, and the mapping table of the one-to-one correspondence between the internal VPI / VCI and the external VPI / VCI is stored in the CAM. The cell carrying the external VPI / VCI input by the framing chip is converted into a cell carrying the corresponding internal VPI / VCI after querying the mapping table, and then sent to the switching chip; while the cell carrying the internal VPI / VCI input by the switching chip After querying the mapping table, the cell is converted into a cell carrying the corresponding external VPI / VCI and sent to the framing chip. The invention realizes that the user can arbitrarily configure the VPI / VCI within the scope allowed by the ATM protocol, and solves the problem of limited use of the VPI / VCI.

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...

AI Technical Summary

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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