NXLD42 OSPF open shortest path first part II kho tài liệu bách khoa

OSPF Open Shortest Path First Part- IIHere we can see only one route, because R1 is in Area 2 and it is not directly connected with area 0.. R1 config-router #no passive-interface s0/0 I

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OSPF (Open Shortest Path First) Part- II Topology

R1 (config) #int fa0/0

R1 (config-if) #ip add 192.168.101.1 255.255.255.0

R1 (config-if) #no shut

R1 (config-if) #int s0/0

R1 (config-if) #ip add 192.168.1.1 255.255.255.0

R2 (config-if) #ip add 192.168.102.1 255.255.255.0

R2 (config-if) #ip add 192.168.1.2 255.255.255.0

R2 (config-if) #ip add 192.168.2.1 255.255.255.0

Figure 1 OSPF Topology

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OSPF (Open Shortest Path First) Part- II

R3 (config-if) #ip add 192.168.103.1 255.255.255.0

R3 (config-if) #ip add 192.168.2.2 255.255.255.0

R3 (config-if) #ip add 192.168.3.1 255.255.255.0

R4 (config-if) #ip add 192.168.104.1 255.255.255.0

R4 (config-if) #ip add 192.168.3.2 255.255.255.0

R4 (config-if) #ip add 192.168.4.1 255.255.255.0

R4 (config-if) #ip add 192.168.7.1 255.255.255.0

R5 (config-if) #ip add 192.168.105.1 255.255.255.0

R5 (config-if) #ip add 192.168.4.2 255.255.255.0

R5 (config-if) #ip add 192.168.5.1 255.255.255.0

R5 (config-if) #int lo1

R5 (config-if) #ip add 170.50.1.1 255.255.255.0

R5 (config-if) #ip add 170.50.2.1 255.255.255.0

R5 (config-if) #ip add 170.50.3.1 255.255.255.0

R5 (config-if) #ip add 170.50.4.1 255.255.255.0

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R5 (config-if) #ip add 170.50.5.1 255.255.255.0

R6 (config-if) #ip add 192.168.106.1 255.255.255.0

R6 (config-if) #ip add 192.168.5.2 255.255.255.0

R6 (config-if) #ip add 192.168.6.1 255.255.255.0

R7 (config-if) #ip add 192.168.107.1 255.255.255.0

R7 (config-if) #ip add 192.168.6.2 255.255.255.0

R7 (config-if) #ip add 170.70.1.1 255.255.255.0

R7 (config-if) #ip add 170.70.2.1 255.255.255.0

R7 (config-if) #ip add 170.70.3.1 255.255.255.0

R7 (config-if) #ip add 170.70.4.1 255.255.255.0

R7 (config-if) #ip add 170.70.5.1 255.255.255.0

R8 (config-if) #ip add 192.168.108.1 255.255.255.0

R8 (config-if) #ip add 192.168.7.2 255.255.255.0

R8 (config-if) #ip add 170.80.1.1 255.255.255.0

R8 (config-if) #ip add 170.80.2.1 255.255.255.0

R8 (config-if) #ip add 170.80.3.1 255.255.255.0

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R8 (config-if) #ip add 170.80.4.1 255.255.255.0

R8 (config-if) #ip add 170.80.5.1 255.255.255.0

 Now we will run routing protocol on each router

R1 (config) #router ospf 100

R1 (config-router) #router-id 1.1.1.1

R1 (config-router) #int fa0/0

R1 (config-if) #ip ospf 100 area 2

R1 (config-router) #int s0/0

R4 (config) #router ei 100

R4 (config-router) #no auto-summary

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R4 (config-router) #network 192.168.7.0

R5 (config-router) #int lo1

R6 (config-router) #router ei 200

R7 (config) #no auto-summary

R7 (config) #network 0.0.0.0

R1#sh ip route

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Here we can see only one route, because R1 is in Area 2 and it is not directly connected with area 0 Each area must be connected with area 0 Now we will create virtual link to connect area 2 with area 0

 Virtual link would be created on edge to edge router

R2 (config) #router os 100

R2 (config-router) #area 1 virtual link 3.3.3.3

R3 (config-router) #area 1 virtual link 2.2.2.2

R1#sh ip route os

R1#ping 192.168.5.2 successful

 OSPF creates three tables

R1#sh ip os neighbor

R1#sh ip os database

R1#sh ip route os

 Passive-Interface

R1 (config-router) #passive-interface default

This command will apply on each interface

R1 (config-router) #no passive-interface s0/0

If we want to make only fa0/0 passive then we need to apply only on fa0/0

R1 (config-router) #passive-interface fa0/0

 OSPF Authentication

R1 (config) #int s0/0

R1 (config-if) #ip ospf authentication message-digest

R1 (config-if) #ip ospf message-digest key 1 md-5 Mani

R1#sh ip ospf neighbor

After 40 sec neighborship will be down

R1#debug ip ospf events

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Mismatch authentication

R1#un all

R2 (config-if) #ip ospf authentication message-digest

R2 (config-if) #ip ospf message-digest key 1 md-5 Mani

Neighborship will be up

 Now we will check hello & hold timers

R1#sh ip ospf int s0/0

Hello – 10 sec Dead 40 sec

We will change the timer

R1 (config-if) #ip ospf hello-interval 5

R1#sh ip os int s0/0

Hello 5 Dead 20

We can see if we change hello, Dead will be changed automatically

R1#sh ip os ne

Neighborship will be break In ospf hello and dead interval must match for the neighborship

R1#clear ip os process

Yes

R1#debug ip os events

Mismatch hello parameter

R – Received

C – Configured

R2 (config-if) #ip os hello-interval 5

Neighborship will be build-up

Now we will change Dead interval

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R2 (config-if) #ip os dead-interval 15

R2#sh ip int os s0/0

When we change dead, hello will not change automatically

R2#debug ip os events

R2#un all

R1 (config-if) #ip os dead-interval 15

Neighborship will be buildup

Now OSPF domain should be communicated with Eigrp 100

 For that we will perform redistribution

R4 (config-router) #redistribute ei 100

R1#sh ip route os

E2 – 192.168.108.0

E2 – 192.168.7.0

By default it would advertise classfull network If we want to advertise classless also then we need to add a keyword “Subnets”

R4 (config-router) #redistribute ei 100 subnets

R1#sh ip route os

Now we can see the classless network also 172.50.0.0

O – OSPF

E2 – External (Metric type 2)

Now we can see external routes metric is 20 on each route

That is not true

Default metric 20

Here internal cost should be added

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R4 (config-router) #redistribute ei 100 subnets metric-type 1

Metric type 1 means add internal cost also when you exchange routes

R1#sh ip route

OE – 172.30.4.0 (110/212) previously it was 20

Above we redistributed Eigrp in ospf

 Now we will redistribute ospf in Eigrp

R4 (config-router) #redistribute os 100 metric 1 1 1 1 1

R1#sh ip route

Here we can see two types of route, External routes and Inter area routes

There are two types of summarization

1 External Summarization (ASBR)

2 Inter Area Summarization (ABR)

ASBR router is router no 4 here

R4 (config-router) #summary-address 172.80.0.0 255.255.248.0

R1#sh ip route

Here we can see only one route of 172.80.0.0/21

R1#ping 172.80.1.1

Successful

Now we will remove it

R4 (config-router) #no summary-address 172.80.0.0 255.255.248.0

 Now we will summarize inter area routes

It will perform on ABR

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We will summarize the network 172.50.0.0 network For that ABR is R5

R5 (config-router) #area 3 range 172.50.0.0 255.255.248.0

R1#sh ip route os

Here we can see summarized inter area routes

R1#ping 172.50.1.1

Successful

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