IP路由原理

一.什么是路由

　　路由是指导IP报文发送的路径信息。

二.路由表的构成

　　路由表是路由器转发报文的判断依据

三.路由器单跳操作

四.路由表查找规则

1.选择度量值小的进行转发

2.永远将下一跳地址指向直连路由

3.如果路由表中没有相匹配的主机路由去匹配就会丢弃，但是如果存在默认路由的话，会默认从默认路由转发。

五.路由的来源

1.直连路由

　　开销小，配置简单，无需人工维护。只能发现本接口所属网段的路由

2.手工配置的静态路由

　　无开销，配置简单，需人工维护，适合简单拓扑结构的网络

3.路由协议发现的动态路由

　　开销大，配置复杂，无需人工维护，适合复杂拓扑结构的网络

六.路由度量值（Metric）

1.路由度量值表示到达折条路由所指目的地址的代价。

2.通常影响路由度量值的因素：

　　线路演示，带宽，线路使用率，线路可信度，跳数，最大传输单元

3.不同路由协议参考的因素不同

七.路由优先级

如果到相同目的地址有多个路由来源，则：

　　a>.以Preference(优先级)确定不同类型优先级；

　　b>.Preference越小，优先级越高；

　　c>.优先级最高的路由被添加进路由表

八.各类路由默认优先级

九.路由环路

　　环路产生的原因：配置错误或协议缺陷

十.实验：

1.单臂路由的配置不同VLAN互通。

以上是一个简单“单臂路由”拓扑图：

a.实现思路：1>.在22层交换机上划分不同的vlan，并将相应的端口加入不同的 VLAN中；

　　　　　2>.在路由器上配置子接口IP位各个部门员工的网关IP；

　　　　 3>.不同的VLAN只要经过三层设备就能成功的访问到其他不同的VLAN了；

b.配置过程如下：

注意：为了操作方便我将“22层核心交换机”更名为core，将“网关出口”更名为gw

22层核心交换机配置如下：

 1 22层核心交换机配置
 2 [Huawei]sysname core
 3 [core]interface GigabitEthernet 0/0/1
 4 [core-GigabitEthernet0/0/1]port link-type access  #将改口配置为access口 
 5 [core-GigabitEthernet0/0/1]quit 
 6 [core]interface GigabitEthernet 0/0/2
 7 [core-GigabitEthernet0/0/2]port link-type access 
 8 [core-GigabitEthernet0/0/2]quit 
 9 [core]interface GigabitEthernet 0/0/3
10 [core-GigabitEthernet0/0/3]port link-type access 
11 [core-GigabitEthernet0/0/3]quit 
12 [core]interface GigabitEthernet 0/0/4
13 [core-GigabitEthernet0/0/4]port link-type access 
14 [core-GigabitEthernet0/0/4]quit 
15 [core]interface GigabitEthernet 0/0/5
16 [core-GigabitEthernet0/0/5]port link-type access 
17 [core-GigabitEthernet0/0/5]quit 
18 [core]interface GigabitEthernet 0/0/10
19 [core-GigabitEthernet0/0/10]port link-type  trunk   #将改口配置为trunk口
20 [core-GigabitEthernet0/0/10]port trunk allow-pass vlan all 
21 [core-GigabitEthernet0/0/10]undo shutdown 
22 [core-GigabitEthernet0/0/10]quit 
23 [core]vlan 10
24 [core-vlan10]port GigabitEthernet 0/0/1  #将端口加入该VLAN10中
25 [core-vlan10]vlan 20
26 [core-vlan20]port GigabitEthernet 0/0/2
27 [core-vlan20]vlan 30
28 [core-vlan30]port GigabitEthernet 0/0/3
29 [core-vlan30]vlan 40
30 [core-vlan40]port GigabitEthernet 0/0/4
31 [core-vlan40]vlan 50
32 [core-vlan50]port GigabitEthernet 0/0/5
33 [core-vlan50]quit 
34 [core]dis vlan 10 to 50   #查看10到50所有连续的VLAN信息
35 --------------------------------------------------------------------------------
36 U: Up;         D: Down;         TG: Tagged;         UT: Untagged;
37 MP: Vlan-mapping;               ST: Vlan-stacking;
38 #: ProtocolTransparent-vlan;    *: Management-vlan;
39 --------------------------------------------------------------------------------
40 
41 VID  Type    Ports                
42 --------------------------------------------------------------------------------
43 10   common  UT:GE0/0/1(U)            
44 20   common  UT:GE0/0/2(U)            
45 30   common  UT:GE0/0/3(U)            
46 40   common  UT:GE0/0/4(U)            
47 50   common  UT:GE0/0/5(U)            
48 
49 VID  Status  Property      MAC-LRN Statistics Description      
50 --------------------------------------------------------------------------------
51 10   enable  default       enable  disable    VLAN 0010                         
52 20   enable  default       enable  disable    VLAN 0020                         
53 30   enable  default       enable  disable    VLAN 0030                         
54 40   enable  default       enable  disable    VLAN 0040                         
55 50   enable  default       enable  disable    VLAN 0050                         
56 [core]

网关出口配置过程如下：

 1 出口网关配置
 2 [Huawei]sysname gw
 3 [gw]interface Ethernet 0/0/0
 4 [gw-Ethernet0/0/0]undo shutdown  #将物理接口配置成不关闭状态 
 5 [gw-Ethernet0/0/0]quit 
 6 [gw]interface Ethernet 0/0/0.1  
 7 [gw-Ethernet0/0/0.1]vlan-type dot1q 10  #将该子接口172封装成trunk,允许VLAN透传。
 8 [gw-Ethernet0/0/0.1]ip address 172.30.1.254 255.255.255.0   #给该虚接口配置一个地址，也是
 9 
10 172.30.1.0/24的网管地址
11 [gw-Ethernet0/0/0.1]undo shutdow  #该接口不启状态
12 [gw-Ethernet0/0/0.1]quit 
13 [gw]interface Ethernet 0/0/0.2
14 [gw-Ethernet0/0/0.2]vlan-type dot1q 20
15 [gw-Ethernet0/0/0.2]ip address 172.30.2.254
16 [gw-Ethernet0/0/0.2]undo shutdown 
17 [gw-Ethernet0/0/0.2]quit 
18 [gw]interface Ethernet 0/0/0.3
19 [gw-Ethernet0/0/0.3]vlan-type dot1q 30
20 [gw-Ethernet0/0/0.3]ip address 172.30.3.254 24
21 [gw-Ethernet0/0/0.3]undo shutdown 
22 [gw-Ethernet0/0/0.3]quit 
23 [gw]interface Ethernet 0/0/0.4
24 [gw-Ethernet0/0/0.4]vlan-type dot1q 40
25 [gw-Ethernet0/0/0.4]ip address 172.30.4.254 24
26 [gw-Ethernet0/0/0.4]undo shutdown 
27 [gw-Ethernet0/0/0.4]quit 
28 [gw]interface Ethernet 0/0/0.5
29 [gw-Ethernet0/0/0.5]vlan-type dot1q 50
30 [gw-Ethernet0/0/0.5]ip address 172.30.5.254 24
31 [gw-Ethernet0/0/0.5]undo shutdown 
32 [gw-Ethernet0/0/0.5]quit 
33 [gw]

运维部门电脑测试结果如下：

 1 PC>
 2 PC>ipconfig
 3 
 4 Link local IPv6 address...........: fe80::5689:98ff:fea7:2066
 5 IPv6 address......................: :: / 128
 6 IPv6 gateway......................: ::
 7 IPv4 address......................: 172.30.3.1
 8 Subnet mask.......................: 255.255.255.0
 9 Gateway...........................: 172.30.3.254
10 Physical address..................: 54-89-98-A7-20-66
11 DNS server........................:
12 
13 PC>ping 172.30.1.1
14 
15 Ping 172.30.1.1: 32 data bytes, Press Ctrl_C to break
16 From 172.30.1.1: bytes=32 seq=1 ttl=127 time=78 ms
17 From 172.30.1.1: bytes=32 seq=2 ttl=127 time=47 ms
18 From 172.30.1.1: bytes=32 seq=3 ttl=127 time=62 ms
19 From 172.30.1.1: bytes=32 seq=4 ttl=127 time=62 ms
20 From 172.30.1.1: bytes=32 seq=5 ttl=127 time=62 ms
21 
22 --- 172.30.1.1 ping statistics ---
23   5 packet(s) transmitted
24   5 packet(s) received
25   0.00% packet loss
26   round-trip min/avg/max = 47/62/78 ms
27 
28 PC>ping 172.30.2.1
29 
30 Ping 172.30.2.1: 32 data bytes, Press Ctrl_C to break
31 From 172.30.2.1: bytes=32 seq=1 ttl=127 time=47 ms
32 From 172.30.2.1: bytes=32 seq=2 ttl=127 time=62 ms
33 From 172.30.2.1: bytes=32 seq=3 ttl=127 time=47 ms
34 From 172.30.2.1: bytes=32 seq=4 ttl=127 time=62 ms
35 From 172.30.2.1: bytes=32 seq=5 ttl=127 time=47 ms
36 
37 --- 172.30.2.1 ping statistics ---
38   5 packet(s) transmitted
39   5 packet(s) received
40   0.00% packet loss
41   round-trip min/avg/max = 47/53/62 ms
42 
43 PC>ping 172.30.3.1
44 
45 Ping 172.30.3.1: 32 data bytes, Press Ctrl_C to break
46 From 172.30.3.1: bytes=32 seq=1 ttl=128 time<1 ms
47 From 172.30.3.1: bytes=32 seq=2 ttl=128 time<1 ms
48 From 172.30.3.1: bytes=32 seq=3 ttl=128 time<1 ms
49 From 172.30.3.1: bytes=32 seq=4 ttl=128 time<1 ms
50 From 172.30.3.1: bytes=32 seq=5 ttl=128 time<1 ms
51 
52 --- 172.30.3.1 ping statistics ---
53   5 packet(s) transmitted
54   5 packet(s) received
55   0.00% packet loss
56   round-trip min/avg/max = 0/0/0 ms
57 
58 PC>ping 172.30.4.1
59 
60 Ping 172.30.4.1: 32 data bytes, Press Ctrl_C to break
61 From 172.30.4.1: bytes=32 seq=1 ttl=127 time=63 ms
62 From 172.30.4.1: bytes=32 seq=2 ttl=127 time=46 ms
63 From 172.30.4.1: bytes=32 seq=3 ttl=127 time=63 ms
64 From 172.30.4.1: bytes=32 seq=4 ttl=127 time=62 ms
65 From 172.30.4.1: bytes=32 seq=5 ttl=127 time=47 ms
66 
67 --- 172.30.4.1 ping statistics ---
68   5 packet(s) transmitted
69   5 packet(s) received
70   0.00% packet loss
71   round-trip min/avg/max = 46/56/63 ms
72 
73 PC>ping 172.30.5.1
74 
75 Ping 172.30.5.1: 32 data bytes, Press Ctrl_C to break
76 From 172.30.5.1: bytes=32 seq=1 ttl=127 time=63 ms
77 From 172.30.5.1: bytes=32 seq=2 ttl=127 time=62 ms
78 From 172.30.5.1: bytes=32 seq=3 ttl=127 time=47 ms
79 From 172.30.5.1: bytes=32 seq=4 ttl=127 time=62 ms
80 From 172.30.5.1: bytes=32 seq=5 ttl=127 time=93 ms
81 
82 --- 172.30.5.1 ping statistics ---
83   5 packet(s) transmitted
84   5 packet(s) received
85   0.00% packet loss
86   round-trip min/avg/max = 47/65/93 ms
87 
88 PC>

c.总结单臂路由的优缺点：

优点：

　　1>实现了不同VLAN的互通。

　　2>.只需要一个物理接口能给多个VLAN配置网关，通过子接口的技术，子接口必须封装802.1Q的trunk协议。

缺点：

　　1>.不同VLAN的数据每次访问都要通过路由器进行路由查找，效率比较低；

　　2>.购买一个路由器设备比购买一个三层交换机要贵的多，性价比低！

2.三层交换配置不同VLAN互通。

a.三层交换机以内置的三层路由转发引擎执行VLAN间路由功能

b.配置过程如下：

三层核心交换机配置如下：

 1 [Huawei]sysname core
 2 [core]interface GigabitEthernet 0/0/1
 3 [core-GigabitEthernet0/0/1]port link-type access  #将改口配置为access口 
 4 [core-GigabitEthernet0/0/1]quit 
 5 [core]interface GigabitEthernet 0/0/2
 6 [core-GigabitEthernet0/0/2]port link-type access 
 7 [core-GigabitEthernet0/0/2]quit 
 8 [core]interface GigabitEthernet 0/0/3
 9 [core-GigabitEthernet0/0/3]port link-type access 
10 [core-GigabitEthernet0/0/3]quit 
11 [core]interface GigabitEthernet 0/0/4
12 [core-GigabitEthernet0/0/4]port link-type access 
13 [core-GigabitEthernet0/0/4]quit 
14 [core]interface GigabitEthernet 0/0/5
15 [core-GigabitEthernet0/0/5]port link-type access 
16 [core-GigabitEthernet0/0/5]quit 
17 [core]interface GigabitEthernet 0/0/10
18 [core-GigabitEthernet0/0/10]port link-type  trunk   #将改口配置为trunk口
19 [core-GigabitEthernet0/0/10]port trunk allow-pass vlan all 
20 [core-GigabitEthernet0/0/10]undo shutdown 
21 [core-GigabitEthernet0/0/10]quit 
22 [core]vlan 10
23 [core-vlan10]port GigabitEthernet 0/0/1  #将端口加入该VLAN10中
24 [core-vlan10]vlan 20
25 [core-vlan20]port GigabitEthernet 0/0/2
26 [core-vlan20]vlan 30
27 [core-vlan30]port GigabitEthernet 0/0/3
28 [core-vlan30]vlan 40
29 [core-vlan40]port GigabitEthernet 0/0/4
30 [core-vlan40]vlan 50
31 [core-vlan50]port GigabitEthernet 0/0/5
32 [core-vlan50]quit 
33 [core]dis vlan 10 to 50   #查看10到50所有连续的VLAN信息
34  --------------------------------------------------------------------------------
35  U: Up;         D: Down;         TG: Tagged;         UT: Untagged;
36  MP: Vlan-mapping;               ST: Vlan-stacking;
37  #: ProtocolTransparent-vlan;    *: Management-vlan;
38  --------------------------------------------------------------------------------
39  
40  VID  Type    Ports                
41  --------------------------------------------------------------------------------
42  10   common  UT:GE0/0/1(U)            
43  20   common  UT:GE0/0/2(U)            
44  30   common  UT:GE0/0/3(U)            
45  40   common  UT:GE0/0/4(U)            
46  50   common  UT:GE0/0/5(U)            
47  
48  VID  Status  Property      MAC-LRN Statistics Description      
49  --------------------------------------------------------------------------------
50  10   enable  default       enable  disable    VLAN 0010                         
51  20   enable  default       enable  disable    VLAN 0020                         
52  30   enable  default       enable  disable    VLAN 0030                         
53  40   enable  default       enable  disable    VLAN 0040                         
54  50   enable  default       enable  disable    VLAN 0050                         
55 [core]
56 [core]interface Vlanif 10  #创建SVI
57 [core-Vlanif10]ip address 172.30.1.254 24  #给当前VLAN10配置一个管理地址。
58 [core-Vlanif10]undo shutdown 
59 [core-Vlanif10]quit 
60 [core]interface Vlanif 20
61 [core-Vlanif20]ip address 172.30.2.254 24
62 [core-Vlanif20]undo shutdown 
63 [core-Vlanif20]quit 
64 [core]interface Vlanif 30
65 [core-Vlanif30]ip address 172.30.3.254 24
66 [core-Vlanif30]undo shutdown 
67 [core-Vlanif30]quit 
68 [core]interface Vlanif 40
69 [core-Vlanif40]ip address 172.30.4.254 24
70 [core-Vlanif40]undo shutdown 
71 [core-Vlanif40]quit 
72 [core]interface Vlanif 50
73 [core-Vlanif50]ip address 172.30.5.254 24
74 [core-Vlanif50]undo shutdown 
75 [core-Vlanif50]quit

运维部门电脑测试结果如下：

 1 PC>ipconfig
 2 
 3 Link local IPv6 address...........: fe80::5689:98ff:fea7:2066
 4 IPv6 address......................: :: / 128
 5 IPv6 gateway......................: ::
 6 IPv4 address......................: 172.30.3.1
 7 Subnet mask.......................: 255.255.255.0
 8 Gateway...........................: 172.30.3.254
 9 Physical address..................: 54-89-98-A7-20-66
10 DNS server........................:
11 
12 PC>ping 172.30.1.1
13 
14 Ping 172.30.1.1: 32 data bytes, Press Ctrl_C to break
15 From 172.30.1.1: bytes=32 seq=1 ttl=127 time=31 ms
16 From 172.30.1.1: bytes=32 seq=2 ttl=127 time=15 ms
17 From 172.30.1.1: bytes=32 seq=3 ttl=127 time<1 ms
18 From 172.30.1.1: bytes=32 seq=4 ttl=127 time=47 ms
19 From 172.30.1.1: bytes=32 seq=5 ttl=127 time=16 ms
20 
21 --- 172.30.1.1 ping statistics ---
22   5 packet(s) transmitted
23   5 packet(s) received
24   0.00% packet loss
25   round-trip min/avg/max = 0/21/47 ms
26 
27 PC>ping 172.30.2.1
28 
29 Ping 172.30.2.1: 32 data bytes, Press Ctrl_C to break
30 From 172.30.2.1: bytes=32 seq=1 ttl=127 time=47 ms
31 From 172.30.2.1: bytes=32 seq=2 ttl=127 time<1 ms
32 From 172.30.2.1: bytes=32 seq=3 ttl=127 time<1 ms
33 From 172.30.2.1: bytes=32 seq=4 ttl=127 time=32 ms
34 From 172.30.2.1: bytes=32 seq=5 ttl=127 time=46 ms
35 
36 --- 172.30.2.1 ping statistics ---
37   5 packet(s) transmitted
38   5 packet(s) received
39   0.00% packet loss
40   round-trip min/avg/max = 0/25/47 ms
41 
42 PC>ping 172.30.3.1
43 
44 Ping 172.30.3.1: 32 data bytes, Press Ctrl_C to break
45 From 172.30.3.1: bytes=32 seq=1 ttl=128 time<1 ms
46 From 172.30.3.1: bytes=32 seq=2 ttl=128 time<1 ms
47 From 172.30.3.1: bytes=32 seq=3 ttl=128 time<1 ms
48 From 172.30.3.1: bytes=32 seq=4 ttl=128 time<1 ms
49 From 172.30.3.1: bytes=32 seq=5 ttl=128 time<1 ms
50 
51 --- 172.30.3.1 ping statistics ---
52   5 packet(s) transmitted
53   5 packet(s) received
54   0.00% packet loss
55   round-trip min/avg/max = 0/0/0 ms
56 
57 PC>ping 172.30.4.1
58 
59 Ping 172.30.4.1: 32 data bytes, Press Ctrl_C to break
60 From 172.30.4.1: bytes=32 seq=1 ttl=127 time=31 ms
61 From 172.30.4.1: bytes=32 seq=2 ttl=127 time=31 ms
62 From 172.30.4.1: bytes=32 seq=3 ttl=127 time=16 ms
63 From 172.30.4.1: bytes=32 seq=4 ttl=127 time=31 ms
64 From 172.30.4.1: bytes=32 seq=5 ttl=127 time=16 ms
65 
66 --- 172.30.4.1 ping statistics ---
67   5 packet(s) transmitted
68   5 packet(s) received
69   0.00% packet loss
70   round-trip min/avg/max = 16/25/31 ms
71 
72 PC>ping 172.30.5.1
73 
74 Ping 172.30.5.1: 32 data bytes, Press Ctrl_C to break
75 From 172.30.5.1: bytes=32 seq=1 ttl=127 time=16 ms
76 From 172.30.5.1: bytes=32 seq=2 ttl=127 time=15 ms
77 From 172.30.5.1: bytes=32 seq=3 ttl=127 time=16 ms
78 From 172.30.5.1: bytes=32 seq=4 ttl=127 time<1 ms
79 From 172.30.5.1: bytes=32 seq=5 ttl=127 time=31 ms
80 
81 --- 172.30.5.1 ping statistics ---
82   5 packet(s) transmitted
83   5 packet(s) received
84   0.00% packet loss
85   round-trip min/avg/max = 0/15/31 ms
86 
87 PC>

c.三层交换机的优点

　　1>.不用路由器照样实现不同VLAN间的互通；

　　2>.性价比高，功能比普通二层交换机要多的多.

posted @ 2017-04-11 23:10 尹正杰阅读(3471) 评论(0) 编辑收藏举报

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