Design And Implementation Of DOCSIS Cable Modem

In the past years , Internet access , multimedia application and other network applications made a great increase,it lead to require more bandwidth of network .In traditional dial access , it provides 56kbps at most , can not meet requirements of many applications, such as VOD , mutual game,viewing multimedia web-pages .Therefore broadband access will promote the network development and provide a huge merchant chance.At present ,there are two existed networks suitable for broadband access-HFC and DSL.HFC is widely applied in CATV system.In HFC, the backbone line is constituted by febric and subscriber node is connected by coxial cable.There are two advantages in HFC ,one is good shield and the other is very broad bandwidth .Hence,HFC is a ideal choice for broad band access.At present ,the major technology adopted in HFC is cable modem .It can provide up to 40Mbps in downstream and up to lOMbps in upstream as fast as several hundred times of traditional dial access.In this article ,we introduce design and implementation of a high performance .In this article , we describe the design and implementation of cable modem based on Broadcom corporation's high integrated and high performance/price single chip-BCM3348.The article is divide into seven parts.In first chapter, introduce the present developing status of broadband access network briefly and describe the HFC in detail.In second chapter, describe the DOCSIS specification .In third chapter, discuss the choice of core chip and software platfonm, hardware module design and whole design method of software at a view of engineering.In fourth chapter and fifth chapter, describe the material design of software and hardware.In sixth part, describe the key problem we met in developing process.In eighth part ,sum up the work in this article.The DCM520 Cable Modem we designed answers for the DOCSIS specification , the design method is advance ,and the product has been made in batches.