主类边界概念：

RIP(Routing Information Protocol)精析03_职场

当路由由左向右传递的时候，经过200，默认172是/16的，比较前16位。如果相同则在同一主类，不相同则认为穿越了主类边界。执行汇总
 
不连续子网：

RIP(Routing Information Protocol)精析03_职场_02

不连续子网：一个主类网络的两个连续子网被另一个网络分隔开
 
RIP第二地址解决V1错误负载均衡
实验拓扑：同一主类，不同子网
RIP(Routing Information Protocol)精析03_职场_03
使用RIPV1进程。因为RIPV1跨主类边界会自动汇总，看下R1的路由表
R    1.0.0.0/8 [120/1] via 13.0.0.3, 00:00:19, FastEthernet0/0
                      [120/1] via 12.0.0.2, 00:00:01, FastEthernet1/0
     12.0.0.0/24 is subnetted, 1 subnets
C       12.0.0.0 is directly connected, FastEthernet1/0
     13.0.0.0/24 is subnetted, 1 subnets
C       13.0.0.0 is directly connected, FastEthernet0/0
负载均衡 这样的路由是有问题的，如果我们配置第二地址，让第二地址和R2，R3的loopback在同一主类，R2，R3会认为loopback口没有跨越主类边界，就不会汇总
R1(config-if)#int f0/0
R1(config-if)#ip address 1.13.1.1 255.255.255.0 sec
R1(config-if)#int f1/0
R1(config-if)#ip address 1.12.1.1 255.255.255.0 sec
 
R2(config)#int f1/0
R2(config-if)#ip address 1.12.1.2 255.255.255.0 sec
 
R3(config)#int f0/0
R3(config-if)#ip address 1.13.1.3 255.255.255.0 sec
 
再看下R1的路由表
Gateway of last resort is not set
 
     1.0.0.0/8 is variably subnetted, 6 subnets, 2 masks
R       1.0.0.0/24 [120/1] via 13.0.0.3, 00:00:11, FastEthernet0/0
                   [120/1] via 12.0.0.2, 00:00:26, FastEthernet1/0
R       1.0.0.0/8 [120/1] via 12.0.0.2, 00:02:18, FastEthernet1/0
                  [120/1] via 13.0.0.3, 00:02:23, FastEthernet0/0
C       1.12.1.0/24 is directly connected, FastEthernet1/0
C       1.13.1.0/24 is directly connected, FastEthernet0/0
R       1.20.2.0/24 [120/1] via 1.12.1.2, 00:00:26, FastEthernet1/0
R       1.30.3.0/24 [120/1] via 1.13.1.3, 00:00:11, FastEthernet0/0
 
水平分割
R1和R2，R3建立邻居关系，R3要想将路由传给R2，在R1上关闭水平分割，观察现象：
接口下no ip slip

RIP(Routing Information Protocol)精析03_休闲_04

RIP三种版本的区别:

RIP(Routing Information Protocol)精析03_休闲_05

分别看下R1 R3的路由表
R1：
Gateway of last resort is not set
 
     1.0.0.0/32 is subnetted, 1 subnets
C       1.1.1.1 is directly connected, Loopback0
     12.0.0.0/24 is subnetted, 1 subnets
C       12.0.0.0 is directly connected, FastEthernet0/0
 
R3：
R    1.0.0.0/8 [120/2] via 23.0.0.2, 00:00:14, FastEthernet1/0
     3.0.0.0/32 is subnetted, 1 subnets
C       3.3.3.3 is directly connected, Loopback0
     23.0.0.0/24 is subnetted, 1 subnets
C       23.0.0.0 is directly connected, FastEthernet1/0
R    12.0.0.0/8 [120/1] via 23.0.0.2, 00:00:18, FastEthernet1/0
R1上没有任何通过RIP学来的路由，R3上有R1环回口路由和12网段的路由。这是怎么回的事啊？
                           默认                  V1                   V2
发                         v1                    v1                    v2
收                        v1v2                   v1                    v2  
版本调试命令：
R1(config-if)#ip rip receive version ?
R1(config-if)#ip rip send version ?
 
RIP的触发更新：
注意和RIP防环机制的触发更新区分开，不是一个概念，前者用来防环，默认执行。此讲触发更新是抑制组播更新，只在拓扑发生变化的时候发送更新消息

RIP(Routing Information Protocol)精析03_休闲_06

interface Serial1/0
 ip address 12.0.0.1 255.255.255.0
 ip rip triggered
 serial restart-delay 0

RIP(Routing Information Protocol)精析03_CCNP CISCO RIP_07

在触发更新面前，计时器形同虚设了。
看下R2的路由表
Gateway of last resort is not set
 
     1.0.0.0/32 is subnetted, 1 subnets
R       1.1.1.1 [120/1] via 12.0.0.1, 00:00:57, Serial1/0
翻动一下R1的loopback
     1.0.0.0/32 is subnetted, 1 subnets
R       1.1.1.1 [120/1] via 12.0.0.1, 00:00:03, Serial1/0