相关调试命令：
show frame-relay lmi show frame-relay map show frame-relay pvc show frame-relay route show interfaces serial
4. 帧中继 Multipoint 配置实例:
Router1:
interface serial 0
encapsulation frame-reply !
interface serial 0.1 multipoint
ip address 172.16.1.2 255.255.255.0
frame-reply map ip 172.16.1.1 201 broadcast frame-reply map ip 172.16.1.3 301 broadcast frame-reply map ip 172.16.1.4 401 broadcast !
Router2:
interface serial 0
encapsulation frame-reply !
interface serial 0.1 multipoint
ip address 172.16.1.1 255.255.255.0
frame-reply map ip 172.16.1.2 102 broadcast frame-reply map ip 172.16.1.3 102 broadcast frame-reply map ip 172.16.1.4 102 broadcast !
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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 设置ISDN交换类型 接口设置 设置PPP封装 设置协议地址与电话号码的映射 启动PPP多连接 设置启动另一个B通道的阈值 显示ISDN有关信息 命令 1isdn switch-type switch-type interface bri 0 encapsulation ppp dialer map protocol next-hop-address [name hostname] [broadcast] [dial-string] ppp multilink dialer load-threshold load 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 Australia basic-ts013 Europe basic-1tr6 basic-nwnet3 basic-net3 交换机类型 Australian TS013 switches German 1TR6 ISDN switches Norway NET3 switches (phase 1) 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 22
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 ！
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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 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。 设置接口支持PPP回拨 在全局模式下为PPP回拨设置映射类别 通过查找注册在dialer map里的主机名来决定回拨. 设置接口要求PPP回拨
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
命令 dialer map protocol address name hostname class classname dial-string ppp callback accept map-class dialer classname dialer callback-server [username] ppp callback request
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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: BRI0:1:PPP 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
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CISCO路由器配置手册(强烈推荐)
