路由协议中分为两种,其中静态路由在小型企业网络中深受青睐,通过管理员手工配置,节省链路开销。默认,浮动路由也是它的应用拓展。本文对静态路由进行了简单讲解。
路由传递依据路由表中的路由
决定设备的三层数据包的转发关系,目标网络能匹配路由表,从相应接口转发。若不能匹配路由表,则drop(丢弃)掉该数据包,不会像交换机那样泛洪(广播)。 解析:路由器可以有效隔离广播域,一个接口一个广播域。交换机是所有接口都在一个广播域。
子网掩码长度最长的最优先匹配
选取路由协议中优先级最小的最优先匹配 DIRECT : 0 (直连) OSPF : 10 IS-IS :15 STATIC : 60 (静态) RIP :100 OSPF ASE : 150 OSPF NSSA: 150 IBGP : 256 EBGP : 256
相同路由协议的情况下,选取metric(宽带延时10m 1G)值最小的最优先匹配。 解析:每种协议metric值定义的都不相同,静态路由和路由优先级有关,这个是人为指定的,RIP协议和跳数有关,跳数越小越优先,OSPF协议和带宽有关,带宽最大最优先。metric是用来判定链路质量优劣的。
如果以上都没有路由可以匹配得上,就匹配默认路由。(0.0.0.0 0.0.0.0) (如果还是没有路由可以匹配得上,就直接丢弃)
优点:配置灵活,管理员手工配置,节省链路开销。 缺点:当拓扑发生改变时,需要管理员去每台路由器上修改路由配置。 建议五条以内的外部路由用静态路由协议,五条以上的用动态路由协议。 静态路由协议只能在小规模的企业网络,大型企业用的是动态路由协议。
是静态路由的一种特殊路由,它属于静态路由中的一种,使用它是有条件的,只能在末梢网络中使用。
指的是配置两条静态路由,默认选取链路质量优(宽带大的)作为主路径,当主路径出现故障时,由带宽较小的备份路由顶替,保持网络的不中断。(是主路径的备份)
命令
ip route-static 0.0.0.0 0.0.0.0 15.1.1.2 preference 61 设置默认路由的优先级为61,为主路径设备:4台PC机,2个交换机,3个路由器
全网通信,运用浮动路由进行备份
首先两边是两个单臂路由,之后三个路由进行静态路由,最后在R1和R2之间搭一条线进行浮动路由设置。
SW1上
# sysname sw1 # vlan batch 10 20 # cluster enable ntdp enable ndp enable # drop illegal-mac alarm # diffserv domain default # drop-profile default # aaa authentication-scheme default authorization-scheme default accounting-scheme default domain default domain default_admin local-user admin password simple admin local-user admin service-type http # interface Vlanif1 # interface MEth0/0/1 # interface Ethernet0/0/1 port link-type access port default vlan 10 # interface Ethernet0/0/2 port link-type access port default vlan 20 # interface Ethernet0/0/3 # interface Ethernet0/0/4 # interface Ethernet0/0/5 # interface Ethernet0/0/6 # interface Ethernet0/0/7 # interface Ethernet0/0/8 # interface Ethernet0/0/9 # interface Ethernet0/0/10 # interface Ethernet0/0/11 # interface Ethernet0/0/12 # interface Ethernet0/0/13 # interface Ethernet0/0/14 # interface Ethernet0/0/15 # interface Ethernet0/0/16 # interface Ethernet0/0/17 # interface Ethernet0/0/18 # interface Ethernet0/0/19 # interface Ethernet0/0/20 # interface Ethernet0/0/21 # interface Ethernet0/0/22 # interface GigabitEthernet0/0/1 port link-type trunk port trunk allow-pass vlan 2 to 4094 # interface GigabitEthernet0/0/2 # interface NULL0 # user-interface con 0 idle-timeout 0 0 user-interface vty 0 4 # returnSW2上
# sysname sw2 # vlan batch 30 40 # cluster enable ntdp enable ndp enable # drop illegal-mac alarm # diffserv domain default # drop-profile default # aaa authentication-scheme default authorization-scheme default accounting-scheme default domain default domain default_admin local-user admin password simple admin local-user admin service-type http # interface Vlanif1 # interface MEth0/0/1 # interface Ethernet0/0/1 port link-type access port default vlan 30 # interface Ethernet0/0/2 port link-type access port default vlan 40 # interface Ethernet0/0/3 # interface Ethernet0/0/4 # interface Ethernet0/0/5 # interface Ethernet0/0/6 # interface Ethernet0/0/7 # interface Ethernet0/0/8 # interface Ethernet0/0/9 # interface Ethernet0/0/10 # interface Ethernet0/0/11 # interface Ethernet0/0/12 # interface Ethernet0/0/13 # interface Ethernet0/0/14 # interface Ethernet0/0/15 # interface Ethernet0/0/16 # interface Ethernet0/0/17 # interface Ethernet0/0/18 # interface Ethernet0/0/19 # interface Ethernet0/0/20 # interface Ethernet0/0/21 # interface Ethernet0/0/22 # interface GigabitEthernet0/0/1 port link-type trunk port trunk allow-pass vlan 2 to 4094 # interface GigabitEthernet0/0/2 # interface NULL0 # user-interface con 0 idle-timeout 0 0 user-interface vty 0 4 # returnR1上
# sysname R1 # aaa authentication-scheme default authorization-scheme default accounting-scheme default domain default domain default_admin local-user admin password cipher OOCM4m($F4ajUn1vMEIBNUw# local-user admin service-type http # firewall zone Local priority 16 # interface Ethernet0/0/0 ip address 15.1.1.1 255.255.255.0 # interface Ethernet0/0/1 # interface Serial0/0/0 link-protocol ppp # interface Serial0/0/1 link-protocol ppp # interface Serial0/0/2 link-protocol ppp # interface Serial0/0/3 link-protocol ppp # interface GigabitEthernet0/0/0 ip address 13.1.1.1 255.255.255.0 # interface GigabitEthernet0/0/1 # interface GigabitEthernet0/0/1.1 vlan-type dot1q 10 ip address 192.168.10.1 255.255.255.0 # interface GigabitEthernet0/0/1.2 vlan-type dot1q 20 ip address 192.168.20.1 255.255.255.0 # interface GigabitEthernet0/0/2 # interface GigabitEthernet0/0/3 # wlan # interface NULL0 # ip route-static 0.0.0.0 0.0.0.0 13.1.1.2 preference 61 ip route-static 24.1.1.0 255.255.255.0 13.1.1.2 ip route-static 24.1.1.0 255.255.255.0 15.1.1.2 ip route-static 192.168.30.0 255.255.255.0 13.1.1.2 ip route-static 192.168.30.0 255.255.255.0 15.1.1.2 ip route-static 192.168.40.0 255.255.255.0 13.1.1.2 ip route-static 192.168.40.0 255.255.255.0 15.1.1.2 # user-interface con 0 idle-timeout 0 0 user-interface vty 0 4 user-interface vty 16 20 # returnR2上
# sysname R2 # aaa authentication-scheme default authorization-scheme default accounting-scheme default domain default domain default_admin local-user admin password cipher OOCM4m($F4ajUn1vMEIBNUw# local-user admin service-type http # firewall zone Local priority 16 # interface Ethernet0/0/0 ip address 15.1.1.2 255.255.255.0 # interface Ethernet0/0/1 # interface Serial0/0/0 link-protocol ppp # interface Serial0/0/1 link-protocol ppp # interface Serial0/0/2 link-protocol ppp # interface Serial0/0/3 link-protocol ppp # interface GigabitEthernet0/0/0 ip address 13.1.1.2 255.255.255.0 # interface GigabitEthernet0/0/1 ip address 24.1.1.2 255.255.255.0 # interface GigabitEthernet0/0/2 # interface GigabitEthernet0/0/3 # wlan # interface NULL0 # ip route-static 192.168.10.0 255.255.255.0 13.1.1.1 ip route-static 192.168.10.0 255.255.255.0 15.1.1.1 ip route-static 192.168.20.0 255.255.255.0 13.1.1.1 ip route-static 192.168.20.0 255.255.255.0 15.1.1.1 ip route-static 192.168.30.0 255.255.255.0 24.1.1.3 ip route-static 192.168.40.0 255.255.255.0 24.1.1.3 # user-interface con 0 idle-timeout 0 0 user-interface vty 0 4 user-interface vty 16 20 # returnR3上
# sysname R3 # aaa authentication-scheme default authorization-scheme default accounting-scheme default domain default domain default_admin local-user admin password cipher OOCM4m($F4ajUn1vMEIBNUw# local-user admin service-type http # firewall zone Local priority 16 # interface Ethernet0/0/0 # interface Ethernet0/0/1 # interface Serial0/0/0 link-protocol ppp # interface Serial0/0/1 link-protocol ppp # interface Serial0/0/2 link-protocol ppp # interface Serial0/0/3 link-protocol ppp # interface GigabitEthernet0/0/0 ip address 24.1.1.3 255.255.255.0 # interface GigabitEthernet0/0/1 # interface GigabitEthernet0/0/1.1 vlan-type dot1q 30 ip address 192.168.30.1 255.255.255.0 # interface GigabitEthernet0/0/1.2 vlan-type dot1q 40 ip address 192.168.40.1 255.255.255.0 # interface GigabitEthernet0/0/2 # interface GigabitEthernet0/0/3 # wlan # interface NULL0 # ip route-static 13.1.1.0 255.255.255.0 24.1.1.2 ip route-static 15.1.1.0 255.255.255.0 24.1.1.2 ip route-static 192.168.10.0 255.255.255.0 24.1.1.2 ip route-static 192.168.20.0 255.255.255.0 24.1.1.2 # user-interface con 0 idle-timeout 0 0 user-interface vty 0 4 user-interface vty 16 20 # return设置完成后,断开R1与R2之间的g0/0/0 查看备份是否有效 浮动路由有效,实验完成
静态中的默认路由可以比较省事的建立链路连接,浮动路由也可以有效的进行链路的备份,保证通信不中断。但因其需要管理员手动设置,需要大量的重复命令,不太建议用于较多外部路由存在时使用。