Asynchronous transfer mode (ATM) cell recombination and sharing buffer memory system and realization method thereof

Abstract

The invention discloses an asynchronous transfer mode (ATM) cell recombination and sharing buffer memory system, which comprises a permanent virtual circuit (PVC), a chain table, a scanner and a first-in first-out device (FIFO), wherein the PVC is used for receiving cells, an on-chip static random-access memory (SRAM) is used as a receiving buffer memory, the PVC shares the buffer memory, the chain table comprises a FREE chain table for indicating the buffer memory rest space and an ACTIVE chain table for representing the space occupied by a buffer memory packet, the FREE chain table is used for receiving requests of the PVC, transferring the address in the FREE chain table to the PVC and storing the address into the buffer memory through the PVC, the scanner is used for visiting the attribute value and the chain table of the PVC in a fixed time sequence, and the FIFO has the effect that the information of the PVC packet is written into the FIFO after the PVC receives the tail cells of a certain PVC packet. In addition, the invention also discloses a realization method of the ATM cell recombination and sharing buffer memory. The unnecessary cells can be cleared, simultaneously, the operation of releasing the corresponding buffer space is completed, the buffer memory management is fairer and more reasonable, the processing bandwidth is high, and the logic realization is simple.

Description

technical field [0001] The invention belongs to the field of computer communication systems, specifically relates to ATM technology, in particular to an ATM cell recombination shared buffer system. In addition, the invention also relates to a realization method of ATM cell reassembly shared buffer. Background technique [0002] The full name of ATM is "Asynchronous Transfer Mode", and the Chinese name is "Asynchronous Transfer Mode". ATM is a data transmission technology. ATM is a packet switching and multiplexing technology based on cells, and it is a general connection-oriented transmission mode designed for various services. Among them, ATM reassembly is part of the SAR (segmentation and reassembly, segmentation and reassembly) function in the AAL (ATM adaptation layer, ATM adaptation layer) layer of ATM, and is used to complete the reorganization of received ATM cells into a format that can be recognized by the upper layer , such as Ethernet packets, IP packets. [0...

AI Technical Summary

Problems solved by technology

[0005] 1) Hardware implementation often uses external RAM (DDR, SDRAM) as a receiving buffer, and it is difficult to guarantee bandwidth requirements under high-speed traffic conditions

[0006] 2) When congestion occurs, PPD combined with EPD is still difficult to ensure that wrong packets enter the reassembly function, resulting in subsequent traffic vibrations

[0007] 3) Scheduling among multiple PVCs (possibly up to 1K) is required, increasing difficulty and hardware resources

[0008] 4) If the end cell of a certain PVC data packet is still not received, the cells stored before the PVC data packet will not be dispatched, occupying the buffer space and affecting the reception of other PVCs

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