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CISCO技术大总结-连载四
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  作者: memtec
  五、ISDN
  1. 综合数字业务网(ISDN)
  综合数字业务网(ISDN)由数字电话和数据传输服务两部分组成,一般由电话局提供这种服务。ISDN的基本速率接口(BRI)服务提供2个B信道和1个D信道(2B+D)。BRI的B信道速率为64Kbps,用于传输用户数据。D信道的速率为16Kbps,主要传输控制信号。在北美和日本,ISDN的主速率接口(PRI)提供23个B信道和1个D信道,总速率可达1.544Mbps,其中D信道速率为64Kbps。而在欧洲、澳大利亚等国家,ISDN的PRI提供30个B信道和1个64Kbps D信道,总速率可达2.048Mbps。我国电话局所提供ISDN PRI为30B+D。
  2. 基本命令
  任务 命令
  设置ISDN交换类型 isdn switch-type switch-type1
  接口设置 interface bri 0
  设置PPP封装 encapsulation ppp
  设置协议地址与电话号码的映射 dialer map protocol next-hop-address [name hostname] [broadcast] [dial-string]
  启动PPP多连接 ppp multilink
  设置启动另一个B通道的阈值 dialer load-threshold load
  显示ISDN有关信息 show isdn {active | history | memory | services | status [dsl | interface-type number] | timers}
  注:1.交换机类型如下表,国内交换机一般为basic-net3。
  按区域分关键字 交换机类型
  Australia
  basic-ts013 Australian TS013 switches
  Europe
  basic-1tr6 German 1TR6 ISDN switches
  basic-nwnet3 Norway NET3 switches (phase 1)
  basic-net3 NET3 ISDN switches (UK, Denmark, and other nations); covers the Euro-ISDN E-DSS1 signalling system
  primary-net5 NET5 switches (UK and Europe)
  vn2 French VN2 ISDN switches
  vn3 French VN3 ISDN switches
  Japan
  ntt Japanese NTT ISDN switches
  primary-ntt Japanese ISDN PRI switches
  North America
  basic-5ess AT&T basic rate switches
  basic-dms100 NT DMS-100 basic rate switches
  basic-ni1 National ISDN-1 switches
  primary-4ess AT&T 4ESS switch type for the U.S. (ISDN PRI only)
  primary-5ess AT&T 5ESS switch type for the U.S. (ISDN PRI only)
  primary-dms100 NT DMS-100 switch type for the U.S. (ISDN PRI only)
  New Zealand
  basic-nznet3 New Zealand Net3 switches
  3. ISDN实现DDR(dial-on-demand routing)实例:
  设置如下:
  Router1:
  hostname router1
  user router2 password cisco
  !
  isdn switch-type basic-net3
  !
  interface bri 0
  ip address 192.200.10.1 255.255.255.0
  encapsulation ppp
  dialer map ip 192.200.10.2 name router2 572
  dialer load-threshold 80
  ppp multilink
  dialer-group 1
  ppp authentication chap
  !
  dialer-list 1 protocol ip permit
  !
  
  Router2:
  hostname router2
  user router1 password cisco
  !
  isdn switch-type basic-net3
  !
  interface bri 0
  ip address 192.200.10.2 255.255.255.0
  encapsulation ppp
  dialer map ip 192.200.10.1 name router1 571
  dialer load-threshold 80
  ppp multilink
  dialer-group 1
  ppp authentication chap
  !
  dialer-list 1 protocol ip permit
  !
  Cisco路由器同时支持回拨功能,我们将路由器Router1作为Callback Server,Router2作为Callback Client。
  与回拨相关命令:
  任务 命令
  映射协议地址和电话号码,并在接口上使用在全局模式下定义的PPP回拨的映射类别。 dialer map protocol address name hostname class classname dial-string
  设置接口支持PPP回拨 ppp callback accept
  在全局模式下为PPP回拨设置映射类别 map-class dialer classname
  通过查找注册在dialer map里的主机名来决定回拨. dialer callback-server [username]
  设置接口要求PPP回拨 ppp callback request
  设置如下:
  Router1:
  hostname router1
  user router2 password cisco
  !
  isdn switch-type basic-net3
  !
  interface bri 0
  ip address 192.200.10.1 255.255.255.0
  encapsulation ppp
  dialer map ip 192.200.10.2 name router2 class s3 572
  dialer load-threshold 80
  ppp callback accept
  ppp multilink
  dialer-group 1
  ppp authentication chap
  !
  map-class dialer s3
  dialer callback-server username
  dialer-list 1 protocol ip permit
  !
  
  Router2:
  hostname router2
  user router1 password cisco
  !
  isdn switch-type basic-net3
  !
  interface bri 0
  ip address 192.200.10.2 255.255.255.0
  encapsulation ppp
  dialer map ip 192.200.10.1 name router1 571
  dialer load-threshold 80
  ppp callback request
  ppp multilink
  dialer-group 1
  ppp authentication chap
  !
  dialer-list 1 protocol ip permit
  !
  相关调试命令:
  debug dialer
  debug isdn event
  debug isdn q921
  debug isdn q931
  debug ppp authentication
  debug ppp error
  debug ppp negotiation
  debug ppp packet
  show dialer
  show isdn status
  举例:执行debug dialer命令观察router2呼叫router1,router1回拨router2的过程.
  router1#debug dialer
  router2#ping 192.200.10.1
  
  router1#
  00:03:50: %LINK-3-UPDOWN: Interface BRI0:1, changed state to up
  00:03:50: BRI0:1PP callback Callback server starting to router2 572
  00:03:50: BRI0:1: disconnecting call
  00:03:50: %LINK-3-UPDOWN: Interface BRI0:1, changed state to down
  00:03:50: BRI0:1: disconnecting call
  00:03:50: BRI0:1: disconnecting call
  00:03:51: %LINK-3-UPDOWN: Interface BRI0:2, changed state to up
  00:03:52: callback to router2 already started
  00:03:52: BRI0:2: disconnecting call
  00:03:52: %LINK-3-UPDOWN: Interface BRI0:2, changed state to down
  00:03:52: BRI0:2: disconnecting call
  00:03:52: BRI0:2: disconnecting call
  00:04:05: : Callback timer expired
  00:04:05: BRI0:beginning callback to router2 572
  00:04:05: BRI0: Attempting to dial 572
  00:04:05: Freeing callback to router2 572
  00:04:05: %LINK-3-UPDOWN: Interface BRI0:1, changed state to up
  00:04:05: BRI0:1: No callback negotiated
  00:04:05: %LINK-3-UPDOWN: Interface Virtual-Access1, changed state to up
  00:04:05: dialer Protocol up for Vi1
  00:04:06: %LINEPROTO-5-UPDOWN: Line protocol on Interface BRI0:1, changed state
  to up
  00:04:06: %LINEPROTO-5-UPDOWN: Line protocol on Interface Virtual-Access1, chang
  ed state to up
  00:04:11: %ISDN-6-CONNECT: Interface BRI0:1 is now connected to 572
  #router1
  4. ISDN访问首都在线263网实例:
  本地局部网地址为10.0.0.0/24,属于保留地址,通过NAT地址翻译功能,局域网用户可以通过ISDN上263网访问Internet。263的ISDN电话号码为2633,用户为263,口令为263,所涉及的命令如下表:
  任务 命令
  指定接口通过PPP/IPCP地址协商获得IP地址 ip address negotiated
  指定内部和外部端口 ip nat {inside | outside}
  使用ppp/pap作认证 ppp authentication pap callin
  指定接口属于拨号组1 dialer-group 1
  定义拨号组1允许所有IP协议 dialer-list 1 protocol ip permit
  设定拨号,号码为2633 dialer string 2633
  设定登录263的用户名和口令 ppp pap sent-username 263 password 263
  设定默认路由 ip route 0.0.0.0 0.0.0.0 bri 0
  设定符合访问列表2的所有源地址被翻译为bri 0所拥有的地址 ip nat inside source list 2 interface bri 0 overload
  设定访问列表2,允许所有协议 access-list 2 permit any
  具体配置如下:
  hostname Cisco2503
  !
  isdn switch-type basic-net3
  !
  ip subnet-zero
  no ip domain-lookup
  ip routing
  !
  interface Ethernet 0
  ip address 10.0.0.1 255.255.255.0
  ip nat inside
  no shutdown
  !
  interface Serial 0
  shutdown
  no description
s no ip address
  !
  interface Serial 1
  shutdown
  no description
  no ip address
  !
  interface bri 0
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