ADSL技术37315

Slide Title,Body Text,Second Level,Third Level,Fourth Level,Fifth Level,2006,Shenzhen Polytechnic.All rights reserved.,*,ADSL,技术,DSL（,数字用户线路，,Digital Subscriber Line）,是以铜质电话线为传输介质的传输技术组合，它包括,HDSL、SDSL、VDSL、ADSL,和,RADSL,等，一般称之为,xDSL,。,它们主要的区别就是体现在信号传输速度和距离的不同以及上行速率和下行速率对称性的不同这两个方面。,What Is a DSL?,VDSL、HDSL、IDSL、SDSL,等,DSL,技术,DSL Technology,Max.Data Rate(Down/Up)bps,Max.Distancefeet/km,ADSL,8 M/1 M,18,000/5.46,VDSL,52 M/13 M,4,500/1.37,IDSL,144 k/144 k,18,000/5.46,SDSL,768 k/768 k,22,000/6.7,G.SHDSL,2.3 M/2.3 M,28,000/8.52,Maximum data rate and distance assume no impairments.,Maximum data rate is achieved at shortest distance.,Maximum distance is achieved at lowest data rate.,ADSL,ADSL,在一对铜线上支持上行速率640,Kbps,到1,Mbps，,下行速率1,Mbps,到8,Mbps，,有效传输距离在35公里范围以内.,在,Internet,中，浏览,Web,等客户/服务器业务的下行数据量要大得多，因此适于采用下行高速化的,ADSL Modem。,ADSL,技术,不对称数字用户线,ADSL,作为一种传输层的技术，充分利用现有的铜线资源，在一对双绞线上提供上行,640,kbps,下行,8,Mbps,的带宽，从而克服了传统用户的,“,瓶颈,”,，实现了真正意义上的宽带接入。,ADSL,下行带宽中的一部分可以用于语音，因此，不需要另外的线路就可以打电话。与有线电视线路上提供的类似服务不同，在使用,ADSL,时，不必与邻居争夺带宽。在许多情况下，凭借现有的电话线路就可以应用,ADSL。,ADSL,技术(,cont.),A key feature of ADSL is coexistence with POTS.,Transmission of voice and data signals is performed on the same wire pair.,Data circuits are offloaded from the voice switch.,Splitter versus,microfilter,POTS splitter at CO&,Microfilters,at customer premises,几种,ADSL MODEM,接入示意图,以太网接口外置式,ADSL MODEM,接入示意图,几种,ADSL MODEM,接入示意图(,cont.),USB,接口外置式,ADSL MODEM,接入示意图,几种,ADSL MODEM,接入示意图(,cont.),PCI,接口内置式,ADSL MODEM,接入示意图,ADSL Channels and Encoding,Single-carrier modulation technique,CAP Modulation,Multiple-carrier modulation technique,DMT Modulation,ADSL Channels and Encoding(cont.),Data over ADSL:,PPPoE,Data over ADSL:,PPPoE,(cont.),Data over ADSL:,PPPoE,(cont.),Data over ADSL:,PPPoE,(cont.),Ethernet frame carrying PPP frame,Service provider end:,DSLAM for DSL connection termination,Aggregation router for PPP session termination,Subscriber end:,DSL modem for DSL connection termination,PPPoE,client for PPP session termination,The client device is the PC or the router at the CPE,Data over ADSL:,PPPoE,(cont.),IP is assigned to,PPPoE,client functioning device.,A CPE router can connect multiple users via a single ADSL connection using NAT/PAT and DHCP.,Configuration of a Cisco Router as the,PPPoE,Client,Configure an Ethernet interface,Configure a dialer interface,Configure PAT,Configure DHCP server,Configure a static default route,Example:CPE as the,PPPoE,Clientover the Ethernet Interface,Example:CPE as the,PPPoE,Clientover the Ethernet Interface (cont.),知识扩充,Configuration of a,PPPoE,Client,PPPoE,Client Configuration,Configures the Ethernet interface,interface,ethernet,number,router(,config,)#,pppoe,enable,router(,config,-if)#,pppoe,-client dial-pool-number,number,router(,config,-if)#,Enables,PPPoE,on Ethernet interface,Binds a dialer profile to the Ethernet interface,Example:Configuring,PPPoE,Client,Configuration of the,PPPoE,DSL Dialer Interface,Configuring the,PPPoE,Dialer Interface,Configures the dialer interface.,interface dialer,number,router(,config,)#,encapsulation,ppp,router(,config,-if)#,ip,address negotiated,router(,config,-if)#,Specifies PPP encapsulation for the dialer interface.,Sets IP address to be negotiated with the remote peer using IPCP.,Configuring the,PPPoE,Dialer Interface(Cont.),Binds dialer interface to the dialer pool,dialer pool,pool_number,router(,config,-if)#,ip mtu,mtu,_size,router(,config,-if)#,ppp,authentication chap,callin,router(,config,-if)#,Reduces the maximum Ethernet payload size because the,PPPoE,header requires 8 bytes,(Optional)Configures PPP authentication CHAP,Example:Configuring the,PPPoE,Dialer Interface,Configuration of PAT,Port Address Translation,Configure PAT,Specifies the addresses that may be translated,access-list,ACL_num,permit|deny,protocol,source_network,source_wildcard,destination_network,destination_wildcard,router(,config,)#,ip nat,inside source list,ACL_num,interface,interface,number,overload,router(,config,)#,ip nat,inside|outside,router(,config,-if)#,Enables dynamic translation of addresses using the assigned IP address of the interface,Specifies the interface as inside or outside related to PAT,Example:PAT Configuration,Configuration of DHCP to Scale DSL,Configure a DHCP Server,Enables a DHCP pool for use by hosts and enters DHCP pool configuration mode.,ip dhcp,pool,pool_name,router(,config,)#,import all,router(,dhcp,-,config,)#,network,network_address,subnet_mask,router(,dhcp,-,config,)#,Imports DNS and WINS information from IPCP.,Specifies the network and subnet mask of the pool.,default-router,address,router(,dhcp,-,config,)#,Specifies the default router for the pool to use.,Example:DHCP Server Configuration,Configuration of a Static Default Route,Configuring a Static Default Route,The CPE can use a static default route to reach all remote destinations.,ip,route 0.0.0.0 0.0.0.0,interface,number,router(,config,)#,Example:Static Default Route,Verifying a,PPPoE,Configuration,Verifying a,PPPoE,Configuration,Displays,PPPoE