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: BRI0:1: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 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