Switch and Router Technology-27-OSPF Route Redistribution

OSPF advanced configuration

1. Route redistribution
2. NSSA area
3. Virtual link

Route redistribution purpose

Connection of different autonomous systems

1. BGP protocol

2. Routing redistribution

Routes requiring redistribution

OSPF redistributes to RIP, default route, static route, direct route

Basic Concepts

In large enterprises, multiple routing protocols may be used in the same network. In order to realize the coordinated work of multiple routing protocols, routers can use routing protocols.Redistribution broadcasts the learned routes of one routing protocol through another routing protocol, so that all parts of the network can be connected.In order to achieve redistribution, routers must run multiple routing protocols at the same time, so that each routing protocol can fetch all or part of the routes of other protocols in the routing table to broadcast

Path type of route for redistribution into OSPF autonomous system

Type 1: E1

Internal cost plus external cost (cost value)

The cost is determined by the bandwidth of the link, the higher the bandwidth, the lower the cost

Type 2:E2

Only consider the external cost (cost value)

The cost is determined by the bandwidth of the link, the higher the bandwidth, the lower the cost

Configuration example

Complete this topology and divide it into nine network segments.Assign IP addresses to router interfaces and PC interfaces, and wait for TCP/IP parameters

The first step is to divide the area as shown in the figure, and configure different protocols according to the area map

Configure the default route on R4 0/0 and set the ip address as the default gateway of PC0

Configure a static route on R3 to reach the network segment 192.168.10.0 and announce the OSPF network segment and area

Declare segment and region on R1

Configure the default route on the ISP to go out

Configuring RIP protocol on R2

Complete OSPF static route redistribution on R3 and OSPF default route redistribution on R1

Complete OSP redistribution rip and rip redistribute OSPF on R2

OSPF static route redistribution

R3(config)#router OSPF 1

R3(config-router)#redistribute static metric 100 subnets

OSPF redistributes default routes

R1(config)#router ospf 1

R1(config-router)#default-information originate

OSPF redistributes RIP

R3(config)#router OSPF 1

R2(config-router)#redistribute rip metric 200 subnets

RIP Redistribute OSPF

R2(config)#router

R2(config)#router rip

R2(config-router)#redistribute ospf 1 metric 10