一旦网络网关或关键节点出现故障,将对业务造成灾难性故障
而网关在大多数情况下只有一个,无法做到冗余,而本章节讨论的就是怎么对网络节点进行冗余。
![image-20200425151233836](/2020/04/25/shou-tiao-rong-yu-xie-yi-fhrp/image-20200425151233836.png)
HSRP
cisco私有的
![image-20200425151427734](/2020/04/25/shou-tiao-rong-yu-xie-yi-fhrp/image-20200425151427734.png)
比如内网中两个节点先比较各自的IP地址,地址大的最终胜出。
![image-20200425151501103](/2020/04/25/shou-tiao-rong-yu-xie-yi-fhrp/image-20200425151501103.png)
胜出的路由器可以响应虚拟IP地址的请求,而对用户而言,虚拟IP地址就是业务地址。
![image-20200425151603957](/2020/04/25/shou-tiao-rong-yu-xie-yi-fhrp/image-20200425151603957.png)
当负责响应这个虚拟IP地址的设备发生了故障,那么另外一台设备就会及时发现,并且抢过虚拟IP地址的响应。
![image-20200425152021426](/2020/04/25/shou-tiao-rong-yu-xie-yi-fhrp/image-20200425152021426.png)
R1,R2,R3是内网设备,R3模拟PC,R1和R2模拟网关
R1(config)#int lo0
R1(config-if)#ip add 1.1.1.1 255.255.255.0
R1(config-if)#ip ospf 1 area 0
R1(config-if)#int e0/0
R1(config-if)#ip add 192.168.14.1 255.255.255.0
R1(config-if)#no sh
R1(config-if)#ip ospf 1 area 0
R1(config-if)#int e0/1
R1(config-if)#ip add 192.168.123.251 255.255.255.0
R1(config-if)#no sh
=================================
R2(config)#int lo0
R2(config-if)#ip add 2.2.2.2 255.255.255.0
R2(config-if)#ip ospf 1 area 0
R2(config-if)#int e0/0
R2(config-if)#ip add 192.168.24.2 255.255.255.0
R2(config-if)#no sh
R2(config-if)#ip ospf 1 area 0
R2(config-if)#int e0/1
R2(config-if)#ip add 192.168.123.252 255.255.255.0
R2(config-if)#no sh
=====================================
R3(config)#int e0/0
R3(config-if)#ip add 192.168.123.3 255.255.255.0
R3(config-if)#no sh
R3(config-if)#ip route 0.0.0.0 0.0.0.0 192.168.123.254
=========================================
R4(config)#int lo0
R4(config-if)#ip add 4.4.4.4 255.255.255.0
R4(config-if)#ip ospf 1 area 0
R4(config-if)#int e0/0
R4(config-if)#ip add 192.168.14.4 255.255.255.0
R4(config-if)#no sh
R4(config-if)#ip ospf 1 area 0
R4(config-if)#int e0/1
R4(config-if)#ip add 192.168.24.4 255.255.255.0
R4(config-if)#no sh
R4(config-if)#ip ospf 1 area 0
配置HSRP
R1和R2
interface Ethernet0/1
standby 1 ip 192.168.123.254
查看HSRP运行状态
R1#sh standby
Ethernet0/1 - Group 1
State is Active
2 state changes, last state change 00:00:38
Virtual IP address is 192.168.123.254 # 虚拟IP地址
Active virtual MAC address is 0000.0c07.ac01 # 虚拟MAC地址,0000.0c07.ac<standby组号>
Local virtual MAC address is 0000.0c07.ac01 (v1 default)
Hello time 3 sec, hold time 10 sec
Next hello sent in 2.560 secs
Preemption disabled # 默认角色不会被抢占
Active router is local
Standby router is 192.168.123.252, priority 100 (expires in 10.800 sec)
Priority 100 (default 100) # 优先级大的成为active
Group name is "hsrp-Et0/1-1" (default)
R1#show standby brief
P indicates configured to preempt.
|
Interface Grp Pri P State Active Standby Virtual IP
Et0/1 1 100 Active local 192.168.123.252 192.168.123.254
如果优先级一样的,就比较接口IP地址,大的成为active
R1(config)#track 1 interface e0/0 line-protocol # 追踪e0/0链路协议状态
R1(config)#int e0/1
R1(config-if)#standby 1 preempt # 开启抢占,哪个设备优先级高,就会立即变成active
R1(config-if)#standby 1 priority 110 # 修改优先级
R1(config-if)#standby 1 track 1 decrement 20 # 如果track1变成down,那么优先级降低20
VRRP
和HSRP功能一样,只是计时器和名词有些变化
还是上面的拓扑
int e0/1
vrrp 1 ip 192.168.123.254
查看vrrp的运行状态
R1#show vrrp
Ethernet0/1 - Group 1
State is Backup
Virtual IP address is 192.168.123.254
Virtual MAC address is 0000.5e00.0101
Advertisement interval is 1.000 sec # hello间隔变为了1s
Preemption enabled # 抢占默认开启
Priority is 100
Master Router is 192.168.123.252, priority is 100
Master Advertisement interval is 1.000 sec
Master Down interval is 3.609 sec (expires in 3.016 sec) # 死亡时间变为了3s
R1(config-if)#vrrp 1 priority 110
R1(config-if)#vrrp 1 preempt
R1(config-if)#vrrp 1 track 1 decrement 20
GLBP
协议概述
- 使得同一时间可使用多个网关,并且自动检测活跃网关。
- 每组GLBP最多可以有4台作为ip默认网关的成员路由器,这些网关被称为AVF(active virtual forwarder)
- GLBP自动管理虚拟MAC地址的分配,决定谁来负责处理转发的工作,这些功能由AVG(active virtual gateway实现)
- 因此AVG负责分发虚拟MAC,AVF负责转发数据