2018/9/3
HSRP---CISCO私有
在SW2与SW4上配置组路由网关，在两个在PC上配置IP指向SW2/SW4的网关。对于SW2与SW4为了使PC的网关不会因为物理线路的down或是设备的损坏造成PC机的网路失效。
通过HSRP对路由网关进行组设置，使得网关线路做到冗余；
在SW2，SW4上做相同配置（优先级不同）：
Switch(config-if)#standby 1 ip 192.168.10.254 //设置组网关地址
Switch#conf t
Switch(config)#int vlan 10
Switch(config-if)#standby 1 priority 120 //设置该路由在组1中的优先级
Switch(config-if)#standby 1 timers 1 3 //设置连接时间
Switch(config-if)#standby 1 preempt //设置路由抢占，对网关的分配
Switch(config-if)#do wr在PC机上配置：
ip 192.168.10.1/24 192.168.10.254 //指向组网关TRACK
当SW2与R1的线路DOWN时，如果SW2处于ACTIVE状态；那么会产生路由黑洞。
通过track监控数据包的连接情况；当TRACK的线路down时，自动将优先级降低；使STANDBY路由ACTIVE
Switch(config)#track 1 ip route 0.0.0.0 0.0.0.0 reachability
Switch(config-if)#standby 1 ?
authentication Authentication
follow Name of HSRP group to follow
ip Enable HSRP IPv4 and set the virtual IP address
ipv6 Enable HSRP IPv6
mac-address Virtual MAC address
name Redundancy name string
preempt Overthrow lower priority Active routers
priority Priority level
timers Hello and hold timers
track Priority tracking
Switch(config-if)#standby 1 track 1 ?
decrement Priority decrement
shutdown Shutdown group
<cr>
Switch(config-if)#standby 1 track 1 decrement 50当接口DOWN
Switch(config-if)#sh
Switch(config-if)#
*Sep 4 02:09:43.223: %LINK-5-CHANGED: Interface Ethernet0/0, changed state to administratively down
*Sep 4 02:09:44.224: %LINEPROTO-5-UPDOWN: Line protocol on Interface Ethernet0/0, changed state to down
Switch(config-if)#do show track
Track 1
IP route 1.1.1.1 255.255.255.255 reachability
Reachability is Down (no ip route)
2 changes, last change 00:00:33
First-hop interface is unknown
Tracked by:
HSRP Vlan10 1
Switch(config-if)#