本实验提供了两台路由器通过ISDN线路进行连接时的最基本配置，从一个最简单的配置开始研究，有利于对技术的把握。
1.实验目的
通过本实验，读者可以把握以下技能
●配置ISDN交换机类型;
●配置PPP封装;
●配置dialer string;
●配置dialer-group及dialer-list;
●查看有关信息。
2.设备需求
本实验需要以下设备:
●Cisco路由器2台，分别命名为R1和R2，要求每台路由器具有1个ISDN BRI接口。
●2条ISDN线路和相应的NT1及线缆;
●1台终端服务器，如Cisco 2509路由器，及用于反向Telnet的相应电缆;
●1台带有超级终端程序的PC机，以及Console电缆及转接器。
3.拓扑结构及配置说明
本实验的拓扑结构如图7-1所示，R1和R2路由器各连接1条ISDN BRE线路。
图7-1中的"广域网云"代表运营商的ISDN网络，路由器的BRI接口通过NT1连接到ISDN线路上。
各路由器BRI接口的ip地址和所连接线路的ISDN号码见图7-1中的标注。实验要求配置R1和R2，使得R1和R2可以互相ping通。
4.实验配置及监测结果
本实验虽说是最基本的ISDN实验，但它涉及到ISDN配置的要害技术，尤其是有效的监测和查看命令对调试非常重要。
设备和线缆连接好之后，打开所有设各的电源，开始进行实验。
配置清单7-1记录了本实验的操作过程。
配置清单7-1 ISDN的基本配置
第1段：配置ISDN类型并查看其状态
R1#conft
Enter configuration commands, one per line. End with CNTL/Z.
R1(config)#isdn switch-type ?
basic-1 tr61TR6 switch type for Germany
basic-5essLUCent 5ESS switch type for the U.S.
basic-dms1OO Northern Telecom DMS-100 switch type for the U.S.
basic-net3NET3 switch type for UK,Europe,Asia and Australia
basic-niNational ISDN switch type for the U.S.
basic-qsig QSIG switch type
basic-ts013TS013 switch type for Australia (obsolete)
nttNTT switch type for Japan
vn3VN3 and VN4 switch types for France
R1(config)#isdn switch-type basic-net3
R1(config)#int bri 0
R1(config-if)@iio shut
R1(config-if)#^Z
R1#sh isdn status
Global ISDN Switchtype=basic-net3
ISDN BRIO interface
dsL 0,interface ISDN Switchtype=basic-net3
Layer 1 Status:
ACTIVE
Layer 3,Status:
TEI=70,Ces=1,SAPI=0,State=MULTIPLE_FRAME_ESTABLISHED
Layer 3 Status:
0 Active Layer 3 Call(s)
Active dsl 0 CCBs = 0
The Free Channel Mask: 0x80000003
Number of L2 Discards = 0, L2 session ID = 5
Total Allocated ISDN CCBs = 0
R1#
[Resuming connection 1 R2]
R2#conft
Enter configuration commands, one per line. End with CNTL/Z.
R2(config)#isdn switch-type basic-net3
R2(config)#int bri 0
R2(config-if)#no sh
R2(config-if)#^Z
R2#
R2#sh isdn status
Global ISDN Switchtype = basic-net3
ISDN BRIO interface
dsl 0, interface ISDN Switchtype = basic-net3
Layer 1 Status:
ACTIVE
Layer 2 Status:
TEI=66,Ces=1,SAPI=0,State=MULTIPLE_FRAME_ESTABLISHED
Layer 3 Status:
0 Active Layer 3 Call(s)
Active dsl 0 CCBs = 0
The Free Channel Mask: 0x80000003
Total Allocated ISDN CCBs = 0
R2#conft
第2段：配置R1路由器
R1#conft
Enter configuration commands, one per line. End with CNTL/Z.
R1(config)#int bri 0
R1(config-if)#ip addr 192.168.1.1255.255.255.0
R1(config~if)#encapsulation ppp
R1(config-if)#dialer string 80000002
R1(config-if)#dialer-group 1
R1(config-if)#exit
R1(config)#diaaer-list 1 PRotocol ip permit
R1(config)#^Z
R1#
第3段：配置R2路由器
R2#conft
Enter configuration commands, one per line. End with CNTL/Z.
R1(config)#int bri 0
R2(config-if)#ip addr 192.168.1.2 255.255.255.0
R2(config-if)#encap ppp
R2(config-if)#dialer string 80000001
R2(config-if)#dialer-group 1
R2(config-if)#exit
R2(config)#dialer-list 1 prot ip permit
R2(config)#^Z
R2#
第4段：测试配置结果
R1#sh int bri 0
BRIO is up,line protocol is up(spoofing)
Hardware is BRI
Internet address is 192.168.1.1/24
MTU 1500 bytes, BW 64 Kbit, DLY 20000 usec,
reliability 255/255, txioad 1/255, rxioad 1/255
Encapsulation PPP, loopback not set
Last input 00:00:05, output 00:00:05, output hang never
Last clearing of "show interface" counters 02:25:35
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueisig strategy: weighted fair
Output queue: 0/1000/64/0 (size/max total/threshold/drops)
Conversations 0/1/16 (active/max active/max total)
Reserved Conversations 0/0 (allocated/max allocated)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
0 packets input,0 bytes,0 no buffer
Received 0 broadcasts,0 runts,0 giants,0 throttles
0 input errors,0 CRC,0 frame,0 overrun,0 ignored,0 abort
0 packets output,0 bytes,0 underruns
0 output errors,0 collisions,0 interface resets
0 output buffer failures,0 output buffers swapped out
0 carrier transitions
R1#sh int bri 0:1
BRIO:1 is down, Stise protocol is dowN
Hardware is BRI
MTU 1500 bytes, BW 64 Kbit, DLY 20000 usec,
reliability 255/255, txioad 1/255, rxioad 1/255
Encapsulation PPP, loopbacfe not set
Keepalive set (10 see)
LCP Closed
Closed:IPCP
Last input never, output never, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue :0/40 (size/max)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
0 packets input, 0 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
0 packets output, 0 bytes, 0 underruns
0 output errors, 0 collisions, 3 interface resets
0 output buffer failures, 0 output buffers swapped out
0 carrier transitions
R1#conft
Enter configuration commands, one per line. End with CNTL/Z.
R1(config)#logg con
R1(config)#^Z
R1#
R1#debug dialer
Dial on demand events debugging is on
R1#ping 192.168.1.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.1.2, timeout is 2 seconds:
02:27:36:BRO DDR:Dialing cause ip(s=192.168.1..1,d=192.168.1.2)
02:27:36:BRO DDR:Attemptiong to dial 80000002.
02:27:38:%LINK-3-UPDOWN:Interface BRIO:1,changed state to up
02:27:38:%ISDN-6CONNECT:Interface BRIO:1 is now connected to 80000002
!!!
Success rate is 60 percent (3/5), round-trip min/avg/max = 36/37/40 ms
02:27:40:BRO:1 DDR:dialer protocol up
02:27:41:
