一、HSRP配置
目标：
在企业网络到外部的连接方案中，要求不高的条件下可以是单出口。一旦该出口线路出现问题，整个企业网络就不能连接到外网了。为了使得企业网络到外网连接的高可用性，可以设置两个以上的出口，然而多个出口对于内网主机意味着我个网关。主机不能同时使用多个网关，当主机所使用的网关出现故障时，它不能实现网关的自动切换。
配置热备份路由协议
方案：
在出口设备上配置热备份路由协议（HSRP），组成一个HSRP组，组内两个出口设备共享一个虚拟IP地址，该IP地址作为内网主机的网关。
HSRP组成员有主备之分，虚拟IP地址被附加到主设备上。如果主设备线路出故障，备份设备会成为主设备，虚拟IP地址也会迁移过来。这样，不管哪一个出口设备出现问题，不管哪个出口设备在提供外网接入，内网主机的网关都不需要改变。
网络拓扑图如下图所示：
步骤：
步骤一：分别在三台路由器上配置端口IP地址
tarena-R1(config)# interface f0/0 tarena-R1(config-if)#ip address 192.168.1.252 255.255.255.0 tarena-R1(config-if)#no shutdown tarena-R1(config-if)#interface f0/1 tarena-R1(config-if)#ip address 192.168.2.1 255.255.255.0 tarena-R1(config-if)#no shutdown tarena-R2(config)#interface f0/0 tarena-R2(config-if)#ip address 192.168.1.253 255.255.255.0 tarena-R2(config-if)#no shutdown tarena-R2(config-if)#interface f0/1 tarena-R2(config-if)#ip address 192.168.3.1 255.255.255.0 tarena-R2(config-if)#no shutdown tarena-R3(config)#interface f0/0 tarena-R3(config-if)#ip address 192.168.2.2 255.255.255.0 tarena-R3(config-if)#no shutdown tarena-R3(config-if)#interface f0/1 tarena-R3(config-if)#ip address 192.168.3.2 255.255.255.0 tarena-R3(config-if)#no shutdown tarena-R3(config-if)#interface f1/0 tarena-R3(config-if)#ip address 192.168.4.254 255.255.255.0 tarena-R3(config-if)#no shutdown步骤二：在R1和R2上配置到外网的默认路由
tarena-R1(config)#ip route 0.0.0.0 0.0.0.0 192.168.2.2 tarena-R1(config)#end tarena-R1#show ip route Codes: C - connected, S - static, I - IGRP, 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, E - EGP i - IS-IS, 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 192.168.1.2 to network 0.0.0.0 C 192.168.1.0/24 is directly connected, FastEthernet0/0 C 192.168.2.0/24 is directly connected, FastEthernet0/1 S* 0.0.0.0/0 [1/0] via 192.168.2.2 tarena-R1# tarena-R2(config)#ip route 0.0.0.0 0.0.0.0 192.168.3.2 tarena-R2(config)#exit tarena-R2#show ip route Codes: C - connected, S - static, I - IGRP, 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, E - EGP i - IS-IS, 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 192.168.2.2 to network 0.0.0.0 C 192.168.1.0/24 is directly connected, FastEthernet0/0 C 192.168.3.0/24 is directly connected, FastEthernet0/1 S* 0.0.0.0/0 [1/0] via 192.168.3.2步骤三：在R3上配置到企业内网的静态路由
tarena-R3(config)#ip route 192.168.1.0 255.255.255.0 192.168.2.1 tarena-R3(config)#ip route 192.168.1.0 255.255.255.0 192.168.3.1 tarena-R3(config)#end tarena-R3#show ip route Codes: C - connected, S - static, I - IGRP, 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, E - EGP i - IS-IS, 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 S 192.168.1.0/24 [1/0] via 192.168.2.1 [1/0] via 192.168.3.1 C 192.168.2.0/24 is directly connected, FastEthernet0/0 C 192.168.3.0/24 is directly connected, FastEthernet0/1 C 192.168.4.0/24 is directly connected, FastEthernet1/0 tarena-R3#
步骤四：在R1上配置HSRP，指定其优先级为200
HSRP的默认优先级为100，路由器启动后，根据优先级决定谁可以成为活跃路由器，优先级高的将胜出。如果路由器优先级相同，再比较端口IP地址，IP地址大的成为活路跃路由器。
另外，如果优先级低的路由器先启动了，它将成为活跃路由器。优先级高的路由器启动后，发现已有活跃路由器存在，它将接受现状，直到活跃路由器出现故障它才会在重新选举时成为活跃角色。
tarena-R1(config)#interface f0/0 tarena-R1(config-if)#standby 1 ip 192.168.1.254 tarena-R1(config-if)#standby 1 priority 200 %HSRP-6-STATECHANGE: FastEthernet0/0 Grp 1 state Speak -> Standby %HSRP-6-STATECHANGE: FastEthernet0/0 Grp 1 state Standby -> Active
配置HSRP后，通过输出日志可以观察到路由器角色的改变。
步骤五：在R2上配置HSRP，指定其优先级为195
tarena-R2(config)#interface f0/0 tarena-R2(config-if)#standby 1 ip 192.168.1.254 tarena-R2(config-if)#standby 1 priority 195 %HSRP-6-STATECHANGE: FastEthernet0/0 Grp 1 state Speak -> Standby步骤六：分别在R1和R2上查看HSRP信息
tarena-R1#show standby brief P indicates configured to preempt. | Interface Grp Pri P State Active Standby Virtual IP Fa0/0 1 200 Active local 192.168.1.253 192.168.1.254 tarena-R2#show standby brief P indicates configured to preempt. | Interface Grp Pri P State Active Standby Virtual IP Fa0/0 1 195 Standby 192.168.2.252 local 192.168.1.254
步骤七：在内部主机上测试到外网主机的连通性
SERVER>ipconfig FastEthernet0 Connection:(default port) Link-local IPv6 Address.........: FE80::207:ECFF:FE80:557D IP Address......................: 192.168.1.1 Subnet Mask.....................: 255.255.255.0 Default Gateway.................: 192.168.1.254 PC>ping 192.168.4.1 Pinging 192.168.4.1 with 32 bytes of data: Reply from 192.168.4.1: bytes=32 time=0ms TTL=126 Reply from 192.168.4.1: bytes=32 time=0ms TTL=126 Reply from 192.168.4.1: bytes=32 time=0ms TTL=126 Reply from 192.168.4.1: bytes=32 time=1ms TTL=126 Ping statistics for 192.168.4.1 Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), Approximate round trip times in milli-seconds: Minimum = 0ms, Maximum = 1ms, Average = 0ms
步骤八：在R1配置端口跟踪、R2配置占先权
tarena-R1(config)#interface fastEthernet 0/0 tarena-R1(config-if)#standby 1 track f0/1 tarena-R2(config)#interface fastEthernet 0/0 tarena-R2(config-if)#standby 1 preempt
步骤九：关闭R1的f0/1接口，模拟设备故障，查看R2的HSRP信息
tarena-R1(config)#interface fastEthernet 0/1 tarena-R1(config-if)#shutdown tarena-R2#show standby brief P indicates configured to preempt. | Interface Grp Pri P State Active Standby Virtual IP Fa0/0 1 195 Active local unknown 192.168.1.254
结果显示R2已成为活跃路由器，而备份路由器状态未知。虚拟路由器的IP地址192.168.1.254/24也已迁移到R2上了。
步骤十：在R1配置占先权，并激活R1的f0/1接口并查状态
备份路由器成为活跃路由器后，原来的活跃路由器R1即使线路修复也不会重新成为进入活跃状态。
为了使路由器完全根据优先级来决定其状态，需要配置占先权。占先权保证了严格根据优先级来决定哪台设备进入活跃状态。
tarena-R1(config)#interface f0/0 tarena-R1(config-if)#standby 1 preempt tarena-R1(config)#interface f0/1 tarena-R1(config-if)#no shutdown tarena-R1#show standby brief P indicates configured to preempt. | Interface Grp Pri P State Active Standby Virtual IP Fa0/0 1 200 Active local 192.168.1.253 192.168.1.254
二、三层交换配置HSRP
目标：
以三层交换机代替路由器作为网关设备。
方案：
以三层交换机代替路由器作为网关设备，以vlan1作为网关接口
网络拓扑如下图所示：
步骤：
步骤一：分别为三层交换机和路由器配置IP并开启三层交换机路由功能。
SM1(config)#ip routing SM1(config)#interface vlan 1 SM1(config-if)#ip address 192.168.1.252 255.255.255.0 SM1(config-if)#no shutdown SM1(config-if)#eixt SM1(config)#interface fastEthernet 0/1 SM1(config-if)#no switchport SM1(config-if)#ip address 192.168.2.1 255.255.255.0 SM1(config-if)#no shutdown SM2(config)#ip routing SM2(config)#interface vlan 1 SM2(config-if)#ip add 192.168.1.253 255.255.255.0 SM2(config-if)#no shutdown SM2(config-if)#exit SM2(config)#interface f0/1 SM2(config-if)#no switchport SM2(config-if)#ip address 192.168.3.1 255.255.255.0 Router(config)#interface fastEthernet 0/0 Router(config-if)#ip address 192.168.2.2 255.255.255.0 Router(config-if)#no shutdown Router(config-if)#exit Router(config)#interface fastEthernet 0/1 Router(config-if)#ip address 192.168.3.2 255.255.255.0 Router(config-if)#no shutdown Router(config-if)#exit Router(config)#interface fastEthernet 1/0 Router(config-if)#ip address 192.168.4.254 255.255.255.0 Router(config-if)#no shutdown
步骤二：在三层交换机和路由器上配置动态路由，在路由器上查看路由表。
SM1(config)#router rip SM1(config-router)#version 2 SM1(config-router)#no auto-summary SM1(config-router)#network 192.168.1.0 SM1(config-router)#network 192.168.2.0 SM2(config)#router rip SM2(config-router)#version 2 SM2(config-router)#no auto-summary SM2(config-router)#network 192.168.1.0 SM2(config-router)#network 192.168.3.0 Router(config)#router rip Router(config-router)#version 2 Router(config-router)#no auto-summary Router(config-router)#network 192.168.2.0 Router(config-router)#network 192.168.3.0 Router(config-router)#network 192.168.4.0 Router#show ip route Codes: C - connected, S - static, I - IGRP, 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, E - EGP i - IS-IS, 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 192.168.1.0/24 [120/1] via 192.168.3.1, 00:00:10, FastEthernet0/1 [120/1] via 192.168.2.1, 00:00:04, FastEthernet0/0 C 192.168.2.0/24 is directly connected, FastEthernet0/0 C 192.168.3.0/24 is directly connected, FastEthernet0/1 C 192.168.4.0/24 is directly connected, FastEthernet1/0
步骤三：在三层交换机vlan1中配置虚拟网关并设置优先级和占先权
SM1(config)#interface vlan 1 SM1(config-if)#standby 1 ip 192.168.1.254 SM1(config-if)#standby 1 priority 200 SM1(config-if)#standby 1 preempt %HSRP-6-STATECHANGE: Vlan1 Grp 1 state Speak -> Standby %HSRP-6-STATECHANGE: Vlan1 Grp 1 state Standby -> Active SM2(config)#interface vlan 1 SM2(config-if)#standby 1 ip 192.168.1.254 %HSRP-6-STATECHANGE: Vlan1 Grp 1 state Speak -> Standby SM2(config-if)#standby 1 priority 195 SM2(config-if)#standby 1 preempt
步骤四：在三层交换机vlan1中配置端口跟踪，关闭被跟踪接口并查看SM1的HSRP状态
当三层交换机SM1并没有故障，而是上连端口f0/1接口线路损坏时主备无法快速切换，所以要在主设备上配置端口跟踪，确保当主设备线路出现问题时备份设备可以快速切换身份
SM1(config)#interface vlan 1 SM1(config-if)#standby 1 track f0/1 SM1(config)#interface f0/1 SM1(config-if)#shutdown SM1(config-if)#end SM1#show standby brief P indicates configured to preempt. Interface Grp Pri P State Active Standby Virtual IP Vl1 1 1 190 P Standby 192.168.1.253 local 192.168.1.254 SM1#
步骤五：测试网路连通性
模拟主设备故障或被跟踪的端口故障时测试网络的连通性，确保备份设备被启用
server>ping 192.168.4.1 Pinging 192.168.4.1 with 32 bytes of data: Reply from 192.168.4.1: bytes=32 time=1ms TTL=126 Reply from 192.168.4.1: bytes=32 time=1ms TTL=126 Reply from 192.168.4.1: bytes=32 time=14ms TTL=126 Reply from 192.168.4.1: bytes=32 time=15ms TTL=126 Ping statistics for 192.168.4.1: Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), Approximate round trip times in milli-seconds: Minimum = 1ms, Maximum = 15ms, Average = 7ms
三、STP的配置
目标：
二层网络中有可能出现因为线路故障而导致的通信故障，通过冗余线路可以消除因为某一线路故障而导致的网络中断。
但是因为冗余线路的存在，又可能会出现广播风暴、相同帧的不断复制和MAC地址表不稳定。
配置Switch1为vlan1的主根，Switch2为vlan1的次根方案：
为了保证在冗余环境下不会出广播风暴等问题，引入了生成树（STP）协议。通过生成树协议可以把冗余线路上的某一个端口置为阻塞（BLOCKING）状态，防止广播风暴的产生，当某一线路出现故障时，被阻塞的端口自动进入转发（FORWARDING）状态，保证网络的畅通性。
网络拓扑如下图所示：
步骤：
步骤一：将三台交换机相连的端口配置为中继端口
tarena-sw1(config)#interface range f0/12 -13 tarena-sw1(config-if-range)#switchport mode trunk tarena-sw2(config)#interface range f0/12, f0/23 tarena-sw2(config-if-range)#switchport mode trunk tarena-sw3(config)#interface range f0/13 ,f0/23 tarena-sw3(config-if-range)#switchport mode trunk
步骤二：调整优先级设置tarena-sw1为根网桥
根网桥唯一的依据是BID最小。BID分为两个部分：优先级+MAC地址。比较BID时，先比较优先级，如果优先级相同才比较MAC地址。
优先级取值范围是0到65535，默认值为32768。在查看优先级时，即使是默认值看到的也不是32768，因为交换机的优先级采用系统优先级+VLAN编号的方式，所以查看到的VLAN1默认优先级是32769（系统优先级32768+VLAN编号1）。
tarena-sw1(config)# spanning-tree vlan 1 priority 28672 tarena-sw1(config)#exit tarena-sw1#show spanning-tree VLAN0001 Spanning tree enabled protocol ieee Root ID Priority 28673 //默认优先级为32768 Address 0060.478B.607B This bridge is the root Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Bridge ID Priority 28673 (priority 24576 sys-id-ext 1) Address 0060.478B.607B Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Aging Time 20 Interface Role Sts Cost Prio.Nbr Type ----------- ------ --- -------- -------- ---------------------- Fa0/13 Desg FWD 19 128.13 P2p Fa0/12 Desg FWD 19 128.12 P2p
查看到的结果，Root ID部分指的是根网桥信息，Bridge ID部分是当前所操作的交换机信息，如果二者一致表示当前操作的交换机就是根网桥。
四、三层交换配置STP
目标：
配置Switch1为vlan1的次根，Switch2为vlan1的次根。
配置Switch1为vlan2的次根，Switch2为vlan2的次根
方案：
如图网络拓扑如下图所示：
步骤：
步骤一：将四台交换机相连的端口配置为中继端口，分别创建vlan2
SM1(config)#vlan 2 SM1(config)#exit SM1(config)#interface range fastEthernet 0/1-3 SM1(config-if-range)#switchport trunk encapsulation dot1q SM1(config-if-range)#switchport mode trunk SM2(config)#vlan 2 SM2(config)#exit SM2(config)#interface range fastEthernet 0/1-3 SM2(config-if-range)#switchport trunk encapsulation dot1q SM2(config-if-range)#switchport mode trunk Switch1(config)#vlan 2 Switch1(config)#exit Switch1(config)#interface range fastEthernet 0/1-2 Switch1(config-if-range)#switchport mode trunk Switch2(config)#vlan 2 Switch2(config)#exit Switch2(config)#interface range fastEthernet 0/1-2 Switch2(config-if-range)#switchport mode trunk
步骤二：设置SM1为vlan1的主根vlan2的次根，设置SM2为vlan2的主根vlan1的次根并查看
SM1(config)#spanning-tree vlan 1 root primary SM1(config)#spanning-tree vlan 2 root secondary SM1#show spanning-tree VLAN0001 Spanning tree enabled protocol ieee Root ID Priority 24577 Address 00D0.972A.43E5 This bridge is the root Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Bridge ID Priority 24577 (priority 24576 sys-id-ext 1) Address 00D0.972A.43E5 Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Aging Time 20 Interface Role Sts Cost Prio.Nbr Type ---------------- ---- --- --------- -------- -------------------------------- Fa0/2 Desg FWD 19 128.2 P2p Fa0/3 Desg FWD 19 128.3 P2p Fa0/1 Desg FWD 19 128.1 P2p VLAN0002 Spanning tree enabled protocol ieee Root ID Priority 24578 Address 00E0.F9CE.7424 Cost 19 Port 3(FastEthernet0/3) Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Bridge ID Priority 28674 (priority 28672 sys-id-ext 2) Address 00D0.972A.43E5 Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Aging Time 20 Interface Role Sts Cost Prio.Nbr Type ---------------- ---- --- --------- -------- -------------------------------- Fa0/2 Desg FWD 19 128.2 P2p Fa0/3 Root FWD 19 128.3 P2p Fa0/1 Desg FWD 19 128.1 P2p SM2(config)#spanning-tree vlan 1 root secondary SM2(config)#spanning-tree vlan 2 root primary SM2#show spanning-tree VLAN0001 Spanning tree enabled protocol ieee Root ID Priority 24577 Address 00D0.972A.43E5 Cost 19 Port 3(FastEthernet0/3) Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Bridge ID Priority 28673 (priority 28672 sys-id-ext 1) Address 00E0.F9CE.7424 Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Aging Time 20 Interface Role Sts Cost Prio.Nbr Type ---------------- ---- --- --------- -------- -------------------------------- Fa0/2 Desg FWD 19 128.2 P2p Fa0/1 Desg FWD 19 128.1 P2p Fa0/3 Root FWD 19 128.3 P2p VLAN0002 Spanning tree enabled protocol ieee Root ID Priority 24578 Address 00E0.F9CE.7424 This bridge is the root Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Bridge ID Priority 24578 (priority 24576 sys-id-ext 2) Address 00E0.F9CE.7424 Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Aging Time 20 Interface Role Sts Cost Prio.Nbr Type ---------------- ---- --- --------- -------- -------------------------------- Fa0/2 Desg FWD 19 128.2 P2p Fa0/1 Desg FWD 19 128.1 P2p Fa0/3 Desg FWD 19 128.3 P2p
查看到的结果，Root ID部分指的是根网桥信息，Bridge ID部分是当前所操作的交换机信息，如果二者一致表示当前操作的交换机就是根网桥。