Research And Implementation Of Key Technology In High Density POS Linecard

ACR(Access Convergence Router) is a large-capacity and high-performance dual stack core router with large-scale user access converging function. As one of the main interface cards of the ACR, configurable POS line card with high interface density provides a flexible interface number and interface category support for the ACR, and it is the basis of ACR to implement the fuction of large-capacity access converging. This dissertation focuses on researching key technologies of the high-density Line card. Also, this dissertation will apply the research production to design and implementment of LS linecard in ACR, which is comprised of 16 OC3/12 POS interfaces or 4 OC48 interfaces.Aiming at adaptation interface optimization between a link layer chip and packet processing unit under the condition of high interface density, a queue management method based on "Two-level Scheduling + Packet Round Robin" is presented and carried out in the direction of input adaptation interface for multiplexing input data efficiently and reliably; and a PUSH-based terminal cache strategy is presented and carried out in the direction of output adaptation interface for configuring the limited cache resources in the chip to better deal with bust data transmission within short time, which leads to a reduced packet loss probability more efficiently.Aiming at dual table merging of packet classification lookup and route lookup under the condition of high speed, the up to date Logical Table of TCAM is examined in depth, and according to this technology, a parallel lookup solution based on item merging is designed; the solution employs a conventional hardware implementation structure of TCAM+SRAM search engine, by which the efficiency bottleneck of serial lookup is broken, all of the functions of the former dual-time lookup are accomplished by means of single-time lookup and correct lookup results are ensured.In the last part of this dissertation, some embodiments of the key technologies in a hardware system are illustrated. A test environment and test method are designed from the view of the practical applications, and tests the functions and performances of the line card, and it could be seen from the test results, the designs in this dissertation meet the basic function of network processing and performance target demands of the ACR well.