路由

原创

qiu_tianming 2010-01-26 18:20:33 ©著作权

文章标签 职场路由休闲 文章分类 网络安全

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OSI/RM 网络的参考的模型，将网络分为七层：应用层表示层会话层传输层网络层数链层物理层

高层：应用层表示层会话层
低层：物理层数链层网络层

高层面向于应用，低层面向于通信

网络建设的思路从低向高考虑，数据的传输过程从高向低考虑。

TCP/IP体系架构，将网络分为四层：应用层传输层（TCP层）网络层（IP层）网络接口层

网络接口层：V.35 RS232 ETHERNET PPP HDLC FRAME-RELAY ATM

ethernet(以太网):采用了CSMA/CD机制来避免冲突的一种局域网技术
标准的以太网：10M的以太网，早期是HUB连网，后来交换机连接
高速的交换式以太网：100M以上的以太网，采用交换机连接。

IP层：IP ARP/RARP ICMP

IP协议的功能：编址/寻址
IP V4地址的格式：32位二进制，用点分十进制表示。
地址的组成：网络部分+主机部分
子网掩码：连续的“1”标识网络位，用连续的“0”标识主机位
IP地址的分类：A，1-126   B， 128-191    C， 192-223
子网划分：将大的网络划分成更多更小的网络，分割更大的网络，提高地址的利用率。
例：一个公司获得一个C类的地址段，如192.168.1.0/24，现在公司有五个部门，每个部门最多需要30台主机，如何规划地址？
   分析需求：>=5个网段 <=30台主机
   准备知识：2的N次方>=网段需求    子网掩码：128 192 224 240 248 252 254 255

计算：1、 2的N次方>=5====》n=3=====>子网掩码长度24+3=27，255.255.255.224==》△=256-224=32
2、 192.168.1.0 --192.168.1.32--192.168.1.64--192.168.1.96--192.168.1.128--192.168.1.160--192.168.1.192--192.168.1.224

172.16.0.0/16 ==》 172.16.0.0/19，255.255.224.0
172.16.64.0：172.16.64.0--172.16.65.0....172.16.95.0-172.16.95.255
172.16.96.0

ARP协议：将IP地址解析成MAC地址的协议。

RARP协议：将MAC地址解析成IP地址。例DHCP的过程

ICMP协议：测试网络连通性。例 PING

TCP层：TCP UDP
TCP协议，面向连接的可靠传输协议，三次握手机制、确认机制、滑动窗口机制
UDP协议，面向无连接的不可靠的协议

应用层：http dns telnet smtp pop snmp

路由器和交换机

1、路由器的硬件结构：CPU 存储器（RAM，ROM，NVRAM，FLASH）接口
ROM:boot strap miniIOS
RAM：running-config
NVRAM:startup-config
flash:IOS
接口：ethernet fast-ethernet serial bri

2、路由器的启动的过程：
开机自检，装载启动时的引导代码（ROM）----解压、装载IOS（flash\rom\network）---解压、装载配置文件startup-config--->running-config

注：寄存器的值：0X2102/0X2142 最后一个字段是引导字段，“2”表示从FLASH启动倒数第二个字段是配置文件调用的字段，“0X2102”表示调用NVRAM中的startup-config文件；“0X2142”表示不调startup-config

修改寄存器的值的命令：
    在全局配置模式下输入（config）#config-register 0x2102
    在维修模式下输入 rommon>confreg 0x2102
                     rommon>reset

3、路由器和交换机的区别：A、硬件结构上，路由器接口丰富；交换机接口单一，但是接口数量多
B、路由器是低速设备，通过软件生成路由表转发数据；交换机是高速设备，通过硬件快速转发，以MAC地址为转发依据。
C、数由器分割广播域和冲突域，交换机默认只分割冲突域。

路由

路由的概念：1、寻找最佳路径的过程
2、最佳路径

路由的类型：
1、直连路由，当路由器的接口打开且配置了IP地址时，路由器就会添加关于接口所在网段的路由信息，且根据这样的路由信息来转发数据。

2、静态路由，由管理员手工指定到达目标网段所要经过的路径，包含目标（未知）网段、子网掩码、下一跳IP地址

3、默认路由，特殊的静态路由，但是优先级最低。用于未知网段只有一个出口的网络结构。

4、动态路由，由路由协议根据算法自动学习得到的关于目标网段的路径。

例：静态路由的配置与调试

R1

ena
config t
no ip domain-lookup

line console 0
pass cisco
login
logg syn
no exec-timeout

line vty 0 1
pass cisco
login

hostname r1
ena pass cisco
ena secret huayu

interface f1/0
ip add 192.168.1.1 255.255.255.0
no sh

interface s0/0
ip add 192.168.2.1 255.255.255.0
no sh

ip route 0.0.0.0 0.0.0.0 192.168.2.2

ena
config t
no ip domain-lookup

line console 0
pass cisco
login
logg syn
no exec-timeout

line vty 0 1
pass cisco
login

hostname r2
ena pass cisco
ena secret huayu

interface s0/1
ip add 192.168.3.1 255.255.255.0
no sh

interface s0/0
ip add 192.168.2.2 255.255.255.0
no sh

ip route 192.168.1.0 255.255.255.0 192.168.2.1
ip route 192.168.4.0 255.255.255.0 192.168.3.2

PC
1
ip 192.168.1.2 192.168.1.1 24
2
ip 192.168.4.2 192.168.4.1 24

动态路由

动态路由的分类：
距离矢量路由协议，周期性的向邻居广播或组播路由表的备份来更新路由；RIP IGRP
链路状态协议，通过收集全网的接口状态，然后再通过自己的算法算出路由表； OSPF IS-IS
混合路由，结合二者的优点，是思科专有； EIGRP

routing protocol,路由选择协议，RIP IGRP OSPF EIGRP
routed protocol,可路由协议，IP IPX

RIP（routing information protocol,路由信息协议）
version 1
基本特点：1、属于距离矢量路由协议 2、度量：以跳数，最大15跳 3、周期性广播（30S，255.255.255.255）4、有类路由（classful routing protocol）

路由表的形成过程：网络中的路由器在更新周期到达时向邻居发送自己路由表的备份，邻居接收到信息对自己的路由表，将未知或更优的路由条目添加到自己的路由表中，且跳数在原有的基础要增加1。

ena
config t
no ip domain-lookup

line console 0
pass cisco
login
logg syn
no exec-timeout

line vty 0 1
pass cisco
login

hostname r1
ena pass cisco
ena secret huayu

interface s0/0
ip add 192.168.1.1 255.255.255.252
no sh

interface loopback 0
ip address 1.1.1.1 255.255.255.0

router rip
network 192.168.1.0
network 1.1.1.0

ena
config t
no ip domain-lookup

line console 0
pass cisco
login
logg syn
no exec-timeout

line vty 0 1
pass cisco
login

hostname r2
ena pass cisco
ena secret huayu

interface s0/0
ip add 192.168.1.2 255.255.255.252
no sh

interface s0/1
ip add 192.168.1.5 255.255.255.252
no sh

router rip
network 192.168.1.4
network 192.168.1.0

ena
config t
no ip domain-lookup

line console 0
pass cisco
login
logg syn
no exec-timeout

line vty 0 1
pass cisco
login

hostname r3
ena pass cisco
ena secret huayu

interface s0/1
ip add 192.168.1.6 255.255.255.252
no sh

interface l0
ip add 3.3.3.3 255.255.255.0
no sh

router rip
network 192.168.1.4
network 3.3.3.0

*show 静态的查看路由器运行的结果
debug动态的查看路由器正在运行的过程
###################################################

r2#show ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

R    1.0.0.0/8 [120/1] via 192.168.1.1, 00:00:28, Serial0/0
R    3.0.0.0/8 [120/1] via 192.168.1.6, 00:00:26, Serial0/1
     192.168.1.0/30 is subnetted, 2 subnets
C       192.168.1.0 is directly connected, Serial0/0
C       192.168.1.4 is directly connected, Serial0/1

r2#debug ip rip events
RIP event debugging is on
r2#
*Mar 1 00:18:53.939: RIP: sending v1 update to 255.255.255.255 via Serial0/1 (192.168.1.5)
*Mar 1 00:18:53.939: RIP: Update contains 2 routes
*Mar 1 00:18:53.939: RIP: Update queued
*Mar 1 00:18:53.943: RIP: Update sent via Serial0/1
r2#
*Mar 1 00:18:55.215: RIP: received v1 update from 192.168.1.1 on Serial0/0
*Mar 1 00:18:55.215: RIP: Update contains 1 routes
r2#
*Mar 1 00:18:57.223: RIP: received v1 update from 192.168.1.6 on Serial0/1
*Mar 1 00:18:57.223: RIP: Update contains 1 routes
r2#
*Mar 1 00:19:07.943: RIP: sending v1 update to 255.255.255.255 via Serial0/0 (192.168.1.2)
*Mar 1 00:19:07.943: RIP: Update contains 2 routes
*Mar 1 00:19:07.943: RIP: Update queued
*Mar 1 00:19:07.947: RIP: Update sent via Serial0/0
r2#
*Mar 1 00:19:22.715: RIP: received v1 update from 192.168.1.1 on Serial0/0
*Mar 1 00:19:22.715: RIP: Update contains 1 routes
r2#
*Mar 1 00:19:23.795: RIP: sending v1 update to 255.255.255.255 via Serial0/1 (192.168.1.5)
*Mar 1 00:19:23.795: RIP: Update contains 2 routes
*Mar 1 00:19:23.795: RIP: Update queued
*Mar 1 00:19:23.799: RIP: Update sent via Serial0/1
r2#
*Mar 1 00:19:25.779: RIP: received v1 update from 192.168.1.6 on Serial0/1
*Mar 1 00:19:25.779: RIP: Update contains 1 routes
r2#
*Mar 1 00:19:35.635: RIP: sending v1 update to 255.255.255.255 via Serial0/0 (192.168.1.2)
*Mar 1 00:19:35.635: RIP: Update contains 2 routes
*Mar 1 00:19:35.635: RIP: Update queued
*Mar 1 00:19:35.639: RIP: Update sent via Serial0/0

Gateway of last resort is not set

R    1.0.0.0/8 [120/1] via 192.168.1.1, 00:00:22, Serial0/0
R    3.0.0.0/8 is possibly down, routing via 192.168.1.6, Serial0/1
     192.168.1.0/30 is subnetted, 2 subnets
C       192.168.1.0 is directly connected, Serial0/0
C       192.168.1.4 is directly connected, Serial0/1

路由环路
收敛：网络中所有路由器具有全网络的路由，且信息达到一致的状态。

路由环路的产生：周期性的广播及从邻居的接口返回自己更新的路由。

解决办法：1、触发更新 2、抑制计时器
3、水平分割 ip split-horizon 4、路由毒化 5、毒性反转
6、定义最大跳（RIP 16跳）

被动接口（passive）只接收路由的更新，不从该接口广播路由出去。

单播更新，只向某个邻居更新路由，指定要更新的邻居（neighbor）

ena
config t
no ip do lo
line console 0
logg syn
no exec-time
host r1

interface f0/0
no sh
ip add 192.168.1.1 255.255.255.0

interface l0
ip add 1.1.1.1 255.255.255.0
no sh

router rip
passive-interface f0/0
network 1.1.1.0
network 192.168.1.0

未开启被动接口时
r1#   show ip route
     1.0.0.0/24 is subnetted, 1 subnets
C       1.1.1.0 is directly connected, Loopback0
R    2.0.0.0/8 [120/1] via 192.168.1.2, 00:00:02, FastEthernet0/0
R    3.0.0.0/8 [120/1] via 192.168.1.3, 00:00:13, FastEthernet0/0
C    192.168.1.0/24 is directly connected, FastEthernet0/0

R1#debug ip rip events
Mar 1 00:07:15.727: RIP: sending v1 update to 255.255.255.255 via FastEthernet0/0 (192.168.1.1)
*Mar 1 00:07:15.727: RIP: Update contains 1 routes
*Mar 1 00:07:15.727: RIP: Update queued
*Mar 1 00:07:15.731: RIP: Update sent via FastEthernet0/0
r1#
*Mar 1 00:07:22.615: RIP: received v1 update from 192.168.1.3 on FastEthernet0/0
*Mar 1 00:07:22.619: RIP: Update contains 1 routes
r1#
*Mar 1 00:07:28.111: RIP: sending v1 update to 255.255.255.255 via Loopback0 (1.1.1.1)
*Mar 1 00:07:28.111: RIP: Update contains 3 routes
*Mar 1 00:07:28.111: RIP: Update queued
*Mar 1 00:07:28.115: RIP: Update sent via Loopback0
r1#
*Mar 1 00:07:33.975: RIP: received v1 update from 192.168.1.2 on FastEthernet0/0
*Mar 1 00:07:33.975: RIP: Update contains 1 routes

开启被动接口和单播更新

r1(config-router)#passive-interface f0/0
*Mar 1 00:11:20.927: RIP: received v1 update from 192.168.1.2 on FastEthernet0/0
*Mar 1 00:11:20.927: RIP: Update contains 1 routes
r1(config-router)#
*Mar 1 00:11:31.243: RIP: received v1 update from 192.168.1.3 on FastEthernet0/0
*Mar 1 00:11:31.243: RIP: Update contains 1 routes

r1(config-router)#neighbor 192.168.1.2
*Mar 1 00:13:35.743: RIP: sending v1 update to 192.168.1.2 via FastEthernet0/0 (192.168.1.1)
*Mar 1 00:13:35.743: RIP: Update contains 1 routes
*Mar 1 00:13:35.743: RIP: Update queued
*Mar 1 00:13:35.747: RIP: Update sent via FastEthernet0/0

r3#show ip route
R    2.0.0.0/8 [120/1] via 192.168.1.2, 00:00:15, FastEthernet0/0
     3.0.0.0/24 is subnetted, 1 subnets
C       3.3.3.0 is directly connected, Loopback0
C    192.168.1.0/24 is directly connected, FastEthernet0/0

r1#show ip route
    1.0.0.0/24 is subnetted, 1 subnets
C       1.1.1.0 is directly connected, Loopback0
R    2.0.0.0/8 [120/1] via 192.168.1.2, 00:00:02, FastEthernet0/0
R    3.0.0.0/8 [120/1] via 192.168.1.3, 00:00:19, FastEthernet0/0
C    192.168.1.0/24 is directly connected, FastEthernet0/0

version 2
基本特点：1、属于距离矢量路由协议 2、度量：以跳数，最大15跳 3、周期性组播（30S，224.0.0.9）4、无类路由（classless routing protocol）5、支持认证功能

R1
ena
config t
no ip domain-lookup

line console 0
pass cisco
login
logg syn
no exec-timeout

line vty 0 1
pass cisco
login

hostname r1
ena pass cisco
ena secret huayu

interface s0/0
ip add 192.168.1.1 255.255.255.252
no sh

interface l0
ip add 1.1.1.1 255.255.255.0
no sh

router rip
network 192.168.1.0
network 1.1.1.0

R2
ena
config t
no ip domain-lookup

line console 0
pass cisco
login
logg syn
no exec-timeout

line vty 0 1
pass cisco
login

hostname r2
ena pass cisco
ena secret huayu

interface s0/0
ip add 192.168.1.2 255.255.255.252
no sh

interface s0/1
ip add 192.168.1.5 255.255.255.252
no sh

interface s0/2
ip add 192.168.1.9 255.255.255.252
no sh

interface l0
ip add 2.2.2.2 255.255.255.0
no sh

router rip
network 192.168.1.0
network 2.2.2.0

router rip
version 2
network 192.168.1.4
network 192.168.1.8

ena
config t
no ip domain-lookup

line console 0
pass cisco
login
logg syn
no exec-timeout

line vty 0 1
pass cisco
login

hostname r3
ena pass cisco
ena secret huayu

interface s0/1
ip add 192.168.1.6 255.255.255.252
no sh

interface l0
ip add 3.3.3.3 255.255.255.0
no sh

router rip
version 2
network 192.168.1.4
network 3.3.3.0

r4
ena
config t
no ip domain-lookup

line console 0
pass cisco
login
logg syn
no exec-timeout

line vty 0 1
pass cisco
login

hostname r4
ena pass cisco
ena secret huayu

interface s0/2
ip add 192.168.1.10 255.255.255.252
no sh

interface l0
ip add 4.4.4.4 255.255.255.0
no sh

router rip
version 2
network 192.168.1.8
network 4.4.4.0

r1#
*Mar 1 00:08:40.103: RIP: sending v1 update to 255.255.255.255 via Serial0/0 (192.168.1.1)
*Mar 1 00:08:40.103: RIP: Update contains 1 routes
*Mar 1 00:08:40.103: RIP: Update queued
*Mar 1 00:08:40.103: RIP: Update sent via Serial0/0
r1#
*Mar 1 00:08:54.551: RIP: received v2 update from 192.168.1.2 on Serial0/0
*Mar 1 00:08:54.555: RIP: Update contains 5 routes

r1#show ip route
     1.0.0.0/24 is subnetted, 1 subnets
C       1.1.1.0 is directly connected, Loopback0
R    2.0.0.0/8 [120/1] via 192.168.1.2, 00:00:10, Serial0/0
R    3.0.0.0/8 [120/1] via 192.168.1.2, 00:00:10, Serial0/0
R    4.0.0.0/8 [120/1] via 192.168.1.2, 00:00:10, Serial0/0
     192.168.1.0/30 is subnetted, 3 subnets
R       192.168.1.8 [120/1] via 192.168.1.2, 00:00:10, Serial0/0
C       192.168.1.0 is directly connected, Serial0/0
R       192.168.1.4 [120/1] via 192.168.1.2, 00:00:10, Serial0/0

r1#show ip pro
Routing Protocol is "rip"
    Interface             Send Recv Triggered RIP Key-chain
    Serial0/0             1     1 2
    Loopback0             1     1 2

r2(config-router)#
*Mar 1 00:07:44.875: RIP: ignored v1 packet from 192.168.1.1 (illegal version)

r2#show ip route
       2.0.0.0/24 is subnetted, 1 subnets
C       2.2.2.0 is directly connected, Loopback0
R    3.0.0.0/8 [120/1] via 192.168.1.6, 00:00:04, Serial0/1
R    4.0.0.0/8 [120/1] via 192.168.1.10, 00:00:18, Serial0/2
     192.168.1.0/30 is subnetted, 3 subnets
C       192.168.1.8 is directly connected, Serial0/2
C       192.168.1.0 is directly connected, Serial0/0
C       192.168.1.4 is directly connected, Serial0/1

r2#show ip pro
Routing Protocol is "rip"
    Interface             Send Recv Triggered RIP Key-chain
    Serial0/0             2     2
    Serial0/1             2     2
    Serial0/2             2     2
    Loopback0             2     2

解决办法：
r2(config)#interface s0/0
r2(config-if)#ip rip receive version 1

*边界自动汇总（auto-summary）：当经过子网划分的地址通告到网络的边界是，会自动汇总成主有类网络。

RIP V2 认证功能

R1
ena
config t
no ip domain-lookup

line console 0
pass cisco
login
logg syn
no exec-timeout

line vty 0 1
pass cisco
login

hostname r1
ena pass cisco
ena secret huayu

interface s0/0
ip add 192.168.1.1 255.255.255.252
no sh

interface l0
ip add 1.1.1.1 255.255.255.0
no sh

router rip
network 192.168.1.0
network 1.1.1.0

R2
ena
config t
no ip domain-lookup

line console 0
pass cisco
login
logg syn
no exec-timeout

line vty 0 1
pass cisco
login

hostname r2
ena pass cisco
ena secret huayu

key chain huayu
key 1
key-string cisco1234

interface s0/0
ip add 192.168.1.2 255.255.255.252
no sh

interface s0/1
ip add 192.168.1.5 255.255.255.252
no sh
ip rip authentication key-chain huayu 明文验证，只要KEY-STRING内容相同，即验证通过！

interface s0/2
ip add 192.168.1.9 255.255.255.252
no sh
ip rip authentication key-chain hauyu
ip rip authentication mode md5密文验证，需要所有的内容相同，验证才能通过！

interface l0
ip add 2.2.2.2 255.255.255.0
no sh

router rip
network 192.168.1.0
network 2.2.2.0

router rip
version 2
network 192.168.1.4
network 192.168.1.8

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