RIP contiguous

Cho topology:

+ R1 R2 run Ripv1

+ R3 run Ripv2

+  R2 send and receive only Ripv2 update int f0/1

+ R2 send and receive only Ripv1 update int f0/0

L0 : 150.1.x.x/24

R2:

R2#show run | se interface

interface FastEthernet0/0

 ip address 10.1.12.2 255.255.255.0

 ip rip send version 1

 ip rip receive version 1

interface FastEthernet0/1

 ip address 10.1.23.2 255.255.255.0

 ip rip send version 2

 ip rip receive version 2

R1#show ip route

Gateway of last resort is not set

     10.0.0.0/24 is subnetted, 2 subnets

C       10.1.12.0 is directly connected, FastEthernet0/0

R       10.1.23.0 [120/1] via 10.1.12.2, 00:00:13, FastEthernet0/0

     150.1.0.0/24 is subnetted, 1 subnets

C       150.1.1.0 is directly connected, Loopback0

Khi R1 va R2 chay RIPv1 trong goi tin update khong co subnet mas, chi duy nhat mang classful voi classful mask co the advertise. along with contiguous subnets that share the same major network and subnet mask as the transit link between the neighbors. Đây là lý do tại sao R1 học mnagj 150.1.x.0/24 nhưng k học loopback 150.1.x/24 của tất cả các mạng.

Likewise R2 cannot learn the 150.1.1.0/24 network from R1. When traffic is sent to 150.1.1.1 it

is routed based on the RIPv2 summary generated by R4. Since R4 does not have a longer match to the 150.1.1.1 destination, traffic is dropped and an ICMP unreachable message is sent back to the originating host. This problem is inherent to the design of RIPv1 and cannot be fixed in this topology without renumbering subnets or running RIPv2.