详细讲解LAPB背对背连接

王朝other·作者佚名 2008-05-19

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前言

本文为提供示例配置链路接入过程, 平衡式(LAPB) 背对背连接。您能使用它验证您的连接和硬件适当地运作。

硬件和软件版本

此配置是可适用的对所有Cisco IOS软件版本。

DCE边用广域网DCE电缆连接。

DTE边用广域网DTE电缆连接。

欲知关于广域网DCE和DTE电缆的更多信息请点击此处。

网络图

本文根据以下配置：

在此配置， PRasit作为DCE和Spicey是DTE。

配置

Prasit

interface Serial0

ip address 5.0.2.1 255.255.255.0

encapsulation lapb dce

clockrate 64000

Spicey

interface Serial1

ip address 5.0.2.2 255.255.255.0

encapsulation lapb

show命令

使用以下show命令测试您的网络适当地运行：

show controllers

ping

show interfaces

如下所示的输出是输入这些命令的结果在我们在此示例配置使用的设备。

我们能使用 show controllers命令表示， Prasit是DCE和Spicey是DTE。此命令提供您信息物理层是否工作并且什么类型的电缆连接。

prasit#show controllers serial 0

HD unit 0, idb = 0x1D3A2C, driver strUCture at 0x1DAFE8

buffer size 1524 HD unit 0, V.35 DCE cable, clockrate 64000

spicey#show controllers serial 1

HD unit 1, idb = 0x153E94, driver structure at 0x15A1F8

buffer size 1524 HD unit 1, V.35 DTE cable

Prasit

prasit#ping 5.0.2.2

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 5.0.2.2, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 32/36/44 ms

prasit#show interfaces serial 0

Serial0 is up, line protocol is up

Hardware is HD64570

Internet address is 5.0.2.1/24

MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation LAPB, loopback not set

LAPB DCE, state CONNECT, modulo 8, k 7, N1 12032, N2 20

T1 3000, T2 0, interface outage (partial T3) 0, T4 0, Protocol ip

VS 6, VR 6, tx NR 6, Remote VR 6, Retransmissions 0

Queues: U/S frames 0, I frames 0, unack. 0, reTx 0

IFRAMEs 30/31 RNRs 0/0 REJs 0/0 SABM/Es 1/1 FRMRs 0/0 DISCs 0/0

Last input 00:00:15, output 00:00:15, output hang never

Last clearing of "show interface" counters 00:09:37

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: weighted fair

Output queue: 0/1000/64/0 (size/max total/threshold/drops)

Conversations0/1/256 (active/max active/max total)

Reserved Conversations 0/0 (allocated/max allocated)

Available Bandwidth 1158 kilobits/sec

5 minute input rate 0 bits/sec, 0 packets/sec

5 minute output rate 0 bits/sec, 0 packets/sec

47 packets input, 3099 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

40 packets output, 3080 bytes, 0 underruns

0 output errors, 0 collisions, 0 interface resets

0 output buffer failures, 0 output buffers swapped out

0 carrier transitions

DCD=upDSR=upDTR=upRTS=upCTS=up

prasit#

Spicey

spicey#ping 5.0.2.1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 5.0.2.1, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 32/32/32 ms

spicey#show interfaces serial 1

Serial1 is up, line protocol is up

Hardware is HD64570

Internet address is 5.0.2.2/24

MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation LAPB, loopback not set

LAPB DTE, state CONNECT, modulo 8, k 7, N1 12032, N2 20

T1 3000, T2 0, interface outage (partial T3) 0, T4 0, Protocol ip

VS 3, VR 3, tx NR 3, Remote VR 3, Retransmissions 0