I. Preface

We have successfully configured the use of VRRP+MSTP between Layer 3 switches and routers before.
Now let's record the detailed explanation of OSPF configuration of Layer 3 switches/routers.
The requirements are as follows:

5. The company network needs to configure ospf routing protocol on two aggregation layer switches and one core router to realize internal network communication.

Look at the topology first:

Screenshot of the requirements we need to implement;

1.1OSPF

Before OSPF appeared, RIP (Routing Information Protocol) was widely used on the network as an interior gateway protocol.

Because RIP is a routing protocol based on the distance vector algorithm, it has problems such as slow convergence, routing loops, and poor scalability, so it is gradually replaced by OSPF.

OSPF, as a link-state-based protocol, can solve many problems faced by RIP.In addition, OSPF has the following advantages:

OSPF uses multicast to send and receive packets, which can reduce the impact on other routers that do not run OSPF.
OSPF supports Typeless Inter-Domain Routing (CIDR).
OSPF supports load balancing for equal-cost routes.
OSPF supports packet encryption.
Because of the above advantages of OSPF, OSPF is quickly accepted and widely used as an excellent interior gateway protocol.

Two. Experiment started

Look at my topology first:

The Layer 3 switches at the aggregation layer are configured as follows:

First configure the ip address of the following vlan10 port as:

interface Vlanif10
ip address 192.168.10.124 25

The vlan60 configuration of the link router is:

interface Vlanif60
ip address 19.0.0.1 255.255.255.252

Marked in the picture:

interface Vlanif60
ip address 29.0.0.1 255.255.255.252

Release the vlan of the above ports, allowing the specified vlan

OSPF:
Network current network segment anti-mask

ospf 1
area 0.0.0.0
network 192.168.20.0 0.0.0.255
network 192.168.30.0 0.0.0.255
network 11.1.1.1 0.0.0.0
network 19.0.0.1 0.0.0.0
network 192.168.10.0 0.0.0.255

The router configuration is as follows:
First configure the interface ip:
The GigabitEthernet0/0/1 port is configured as follows:

interface GigabitEthernet0/0/1
ip address 19.0.0.2 255.255.255.252

The GigabitEthernet0/0/2 port is configured as follows:

interface GigabitEthernet0/0/2
ip address 29.0.0.2 255.255.255.252

Configure ospf:
Enter ospf 1 to view:

ospf 1
default-route-advertise
area 0.0.0.0
network 19.0.0.2 0.0.0.0
network 29.0.0.2 0.0.0.0
network 33.1.1.1 0.0.0.0

Network current network segment anti-mask

Communication detection:
ping 29.0.0.2

ping 33.1.1.1

OSPF configuration is basically completedneed.

Check the router's routing table;

display ip routing-table

Layer 3 switch: