IPv6 RIPng和RIP 度量值分析

    RIPv2和RIPng都使用值1－16（表示跳数）的度量，最大跳数为15，16表示不可达，在收到路由更新时路由器会递增该度量值，但RIPng和RIPv2的处理方法有重大区别，下面经过实验进行分析；

    R一、R二、R3之间运行RIPng，路由配置以下，其它配置略；

R1的路由配置：

R1(config)#int loo 0

R1(config-if)#ipv6 ripMao enable //RIPng进程Mao只起本地意义，与OSPF的进程号功能相同；接口下配置该命令后，会在全局下生成ipv6 router rip Mao

R1(config-if)#int s1/0      

R1(config-if)#ipv6 rip Mao enable

R1(config-if)#int fa0/0

R1(config-if)#ipv6 rip Mao enable

R2的路由配置：

R2(config)#int loo 0

R2(config-if)#ipv6 rip Ting en

R2(config-if)#int s1/0

R2(config-if)#ipv6 rip Ting enable

R2(config-if)#int fa0/0

R2(config-if)#ipv6 rip Ting enable

R3的路由配置：

R3(config-if)#int fa1/0

R3(config-if)#ipv6 rip

R3(config-if)#ipv6 rip Hai en

R3(config-if)#int fa0/0

R3(config-if)#ipv6 rip Hai en

R3(config-if)#int loo 0

R3(config-if)#ipv6 rip Hai en

在R1与R3之间抓包分析；

抓包可知，R1在通告路由时，将2011::1/128（R1的环回接口ipv6地址）的跳数设置为1，如今R3上查看该路由的状况

R3#show ipv6 route rip

IPv6 Routing Table -default - 11 entries

Codes: C - Connected, L- Local, S - Static, U - Per-user Static route

       B - BGP, HA - Home Agent, MR - MobileRouter, R - RIP

       H - NHRP, I1 - ISIS L1, I2 - ISIS L2, IA- ISIS interarea

       IS - ISIS summary, D - EIGRP, EX - EIGRPexternal, NM - NEMO

       ND - ND Default, NDp - ND Prefix, DCE -Destination, NDr - Redirect

       O - OSPF Intra, OI - OSPF Inter, OE1 -OSPF ext 1, OE2 - OSPF ext 2

       ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSAext 2, l - LISP

R   2001:A:A:12::/64 [120/2]

     via FE80::C802:22FF:FEF8:8,FastEthernet1/0

     via FE80::C801:39FF:FE8C:8,FastEthernet0/0

R   2011::1/128 [120/2]//其跳数置为2，增长了1；

     viaFE80::C801:39FF:FE8C:8, FastEthernet0/0

R   2022::2/128 [120/2]

     via FE80::C802:22FF:FEF8:8,FastEthernet1/0

 

现将R1和R2、R3同时配置RIP协议，配置略，看看路由器R3上的路由的度量值状况与RIPng有什么不一样，在R1和R3之间进行抓包以下：

在R1和R3之间抓包可知，R1通告给R3的1.1.1.1/32路由的跳数值为1，如今R3上查看路由表状况

R3#show ip route rip

Codes: L - local, C - connected, S -static, 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

      i - IS-IS, su - IS-IS summary, 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, H - NHRP, l - LISP

      + - replicated route, % - next hop override

 

Gateway of last resort is not set

 

     1.0.0.0/32 is subnetted, 1 subnets

R        1.1.1.1[120/1] via 13.1.1.1, 00:00:17, FastEthernet0/0 //其跳数值仍是为1，R3并无将其跳数值递增1；

     2.0.0.0/32 is subnetted, 1 subnets

R       2.2.2.2 [120/1] via 23.1.1.1, 00:00:01, FastEthernet1/0

     12.0.0.0/30 is subnetted, 1 subnets

R       12.1.1.0 [120/1] via 23.1.1.1, 00:00:01, FastEthernet1/0

                  [120/1] via 13.1.1.1,00:00:17, FastEthernet0/0

 

在R2上查看路由1.1.1.1/32的路由状况

R2#showip route rip  //RIP路由表

Codes: L - local, C - connected, S -static, 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

      i - IS-IS, su - IS-IS summary, 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, H - NHRP, l - LISP

      + - replicated route, % - next hop override

 

Gateway of last resort is not set

 

     1.0.0.0/32 is subnetted, 1 subnets

R        1.1.1.1[120/2] via 23.1.1.2, 00:00:28, FastEthernet0/0

//其跳数为2

     3.0.0.0/32 is subnetted, 1 subnets

R       3.3.3.3 [120/1] via 23.1.1.2, 00:00:28, FastEthernet0/0

     13.0.0.0/30 is subnetted, 1 subnets

R       13.1.1.0 [120/1] via 23.1.1.2, 00:00:28, FastEthernet0/0

在R2和R3之间的接口抓包可知，R3将1.1.1.1/32通告给R2时，其将其度量值（跳数）加1以后，再传递给R2；

R2#show ipv6 route rip //IPv6 RIP路由表

IPv6 Routing Table - default - 7 entries

Codes: C - Connected, L - Local, S - Static,U - Per-user Static route

      B - BGP, HA - Home Agent, MR - Mobile Router, R - RIP

      H - NHRP, I1 - ISIS L1, I2 - ISIS L2, IA - ISIS interarea

      IS - ISIS summary, D - EIGRP, EX - EIGRP external, NM - NEMO

      ND - ND Default, NDp - ND Prefix, DCE - Destination, NDr - Redirect

      O - OSPF Intra, OI - OSPF Inter, OE1 - OSPF ext 1, OE2 - OSPF ext 2

      ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2, l - LISP

R  2001:A:A:13::/64 [120/2]

    via FE80::C803:35FF:FE30:1C, FastEthernet0/0

R   2011::1/128 [120/3]//R1的环回接口路由跳数为3

    via FE80::C803:35FF:FE30:1C, FastEthernet0/0

R  2033::3/128 [120/2]

    via FE80::C803:35FF:FE30:1C, FastEthernet0/0

从抓包结果能够看出来，R3将2011::1/128路由通告给路由器R2时，其度量值为2，而在R2的路由表中查看为其度量值为3，证实路由器R2将其度量值（跳数）递增1；

 

   总结：RIPng在传递一条起源路由（本路由器产生的）至邻居路由器时，其度量值为1，邻居路由器会将路由的度量值递增1，其实起源路由器将自已归入到目的网络的跳数以内。而RIP是在路由起源的下一跳邻居路由器传递给他的邻居路由器时，才会将该路由的度量值递增1，而不把路由起源的路由器算在达到目的网络的跳数以内。这也是RIPng与RIP的最大不一样之处。