Header GIF
Site is Under Maintenance
Please come back again in...
00 Days
00 Hours
00 Minutes
00 Seconds
Home
• Networking Fundamentals Tutorial •
• OSPF •

Configuring OSPF Route Summarization Tutorial

configuring-ospf-route-summarization.htm

Configuring OSPF Route Summarization

Route summarization in OSPF can only be done in two places in OSPF due to the operational nature of protocol. Because the link state database must be the identical everywhere you can’t just do it in random places. This lab will discuss and demonstrate the configuration and verification of OSPF route summarization.

Real World Application & Core Knowledge

If you have completed Lab 7-8 – Configuring RIP Route Summarization and Lab 8-8 – Configuring EIGRP Route Summarization then you’re no stranger to configuring route summarization.

In a nut shell, route summarization is the process of summarizing subnets into a larger subnet to be advertised to upstream routers for ease of management/troubleshooting and resource conservation.

However when working with OSPF you can only summarize at an ABR or ASBR. There are two types of summarization in OSPF; Inter-Area Summarization and External Summarization.

Inter-Area route summarization can only be done on the Area Boarder Router (ABR) and summarize routes from a particular area into the backbone area.

External Route summarization can only be done on an ASBR and summarizes routes to an external destination.

To configure Inter-Area summarization, you’ll use the area # range network netmask command in OSPF router configuration mode. This command can only be issued on an ABR.

To configure External Route summarization you’d use the summary-address network netmask command in router configuration mode. This command can be executed on any OSPF router but will only function on ASBR’s.

In this lab you’re going to create 4 new loopback interfaces on R4 located in Area 44 then create a summary route advertising all 4 routes as a single route into the backbone area.

Familiarize yourself with the following new command(s);

| Command | Description |
| area # range network netmask | This command is executed in OSPF router configuration mode on an Area Boarder Router (ABR) to configure Inter-Area route summarization. These summary routes will be advertised into the OSPF backbone area (Area 0). |
| summary-address network netmask | This command is executed in OSPF router configuration mode on an Autonomous System Boundary Router (ASBR) to configure External route summarization. |

The following logical topology shown below is used in labs found through out Section 9 – Configuring OSPF;

Lab Prerequisites

  • If you are using GNS3 than load the Stub Area Networking GNS3 topology than start devices; R1, R2, R3, R4, R5 and SW1.
  • Establish a console session with devices R1, R2, R3, R4, R5 and SW1 than load the initial configurations provided below by copying the config from the textbox and pasting it into the respected routers console.

!##################################################
!# Free CCNA Workbook Lab 9-13 R1 Initial Config #
!##################################################
!
enable
configure terminal
!
hostname R1
no ip domain-lookup
!
interface Loopback0
description ### SIMULATED NETWORK ###
ip address 10.90.10.1 255.255.255.0
ip ospf 1 area 1
!
interface Serial0/0
description ### PHYSICAL FRAME RELAY INTERFACE ###
ip address 10.90.245.1 255.255.255.248
ip ospf 1 area 0
encapsulation frame-relay
serial restart-delay 0
frame-relay map ip 10.90.245.5 125 broadcast
frame-relay map ip 10.90.245.4 124 broadcast
frame-relay map ip 10.90.245.2 122 broadcast
no frame-relay inverse-arp
no shut
exit
!
router ospf 1
router-id 1.1.1.1
log-adjacency-changes
auto-cost reference-bandwidth 100000
maximum-paths 1
neighbor 10.90.245.2
neighbor 10.90.245.4
neighbor 10.90.245.5
!
line con 0
logging sync
no exec-timeout
!
end

!##################################################
!# Free CCNA Workbook Lab 9-14 R2 Initial Config #
!##################################################
!
enable
configure terminal
!
hostname R2
no ip domain-lookup
!
interface Loopback0
description ### SIMULATED NETWORK ###
ip address 10.90.20.1 255.255.255.0
ip ospf 1 area 2
!
interface Serial0/0
description ### PHYSICAL FRAME RELAY INTERFACE ###
ip address 10.90.245.2 255.255.255.248
encapsulation frame-relay
ip ospf priority 0
ip ospf 1 area 0
serial restart-delay 0
no frame-relay inverse-arp
frame map ip 10.90.245.1 221 broadcast
frame map ip 10.90.245.4 221
frame map ip 10.90.245.5 221
no shut
!
interface Serial0/2

POINT-TO-POINT LINK TO R3

ip address 10.90.23.1 255.255.255.252
ip ospf 1 area 3
ip ospf hello-interval 1
encapsulation ppp
serial restart-delay 0
no shut
exit
!
router ospf 1
router-id 2.2.2.2
auto-cost reference-bandwidth 100000
log-adjacency-changes
area 3 stub no-summary
!
line con 0
logging sync
no exec-timeout
!
end

!##################################################
!# Free CCNA Workbook Lab 9-14 R3 Initial Config #
!##################################################
!
enable
configure terminal
!
hostname R3
no ip domain-lookup
!
interface Loopback0
description ### SIMULATED NETWORK ###
ip address 10.90.30.1 255.255.255.0
ip ospf 1 area 3
!
interface Serial0/1
description ### POINT-TO-POINT LINK TO R2 ###
ip address 10.90.23.2 255.255.255.252
ip ospf 1 area 3
ip ospf hello-interval 1
encapsulation ppp
no shut
exit
!
router ospf 1
router-id 3.3.3.3
log-adjacency-changes
auto-cost reference-bandwidth 100000
area 3 stub
!
line con 0
logging sync
no exec-timeout
!
end

!##################################################
!# Free CCNA Workbook Lab 9-14 R4 Initial Config #
!##################################################
!
enable
configure terminal
!
hostname R4
no ip domain-lookup
!
interface Loopback0
description ### SIMULATED NETWORK ###
ip address 10.90.40.1 255.255.255.0
ip ospf 1 area 4
!
interface FastEthernet0/0
description ### REAL NETWORK ###
ip address 10.90.145.1 255.255.255.0
ip ospf 1 area 45
no shut
!
interface Serial0/0
description ### PHYSICAL FRAME RELAY INTERFACE ###
ip address 10.90.245.4 255.255.255.248
encapsulation frame-relay
ip ospf priority 0
ip ospf 1 area 0
serial restart-delay 0
no frame-relay inverse-arp
frame map ip 10.90.245.1 421 broadcast
frame map ip 10.90.245.2 421
frame map ip 10.90.245.5 421
no shut
!
interface Serial0/1
description ### POINT-TO-POINT LINK TO R5 ###
ip address 10.90.45.1 255.255.255.252
ip ospf 1 area 45
encapsulation ppp
serial restart-delay 0
no shut
exit
!
router ospf 1
router-id 4.4.4.4
auto-cost reference-bandwidth 100000
log-adjacency-changes
passive-interface fastethernet0/0
!
line con 0
logging sync
no exec-timeout
!
end

!##################################################
!# Free CCNA Workbook Lab 9-14 R5 Initial Config #
!##################################################
!
enable
configure terminal
!
hostname R5
no ip domain-lookup
!
interface Loopback0
description ### SIMULATED NETWORK ###
ip address 10.90.50.1 255.255.255.0
ip ospf 1 area 5
!
interface FastEthernet0/0
description ### REAL NETWORK ###
ip address 10.90.145…2 255.255.255.0
ip ospf cost 65535
ip ospf 1 area 45
no shut
!
interface Serial0/0
description ### PHYSICAL FRAME RELAY INTERFACE ###
ip address 10.90.245.5 255.255.255.248
encapsulation frame-relay
ip ospf priority 0
ip ospf 1 area 0
serial restart-delay 0
no frame-relay inverse-arp
frame map ip 10.90.245.1 521 broadcast
frame map ip 10.90.245.2 521
frame map ip 10.90.245.4 521
no shut
!
interface Serial0/1
description ### POINT-TO-POINT LINK TO R4 ###
ip address 10.90.45.2 255.255.255.252
ip ospf 1 area 45
encapsulation ppp
serial restart-delay 0
no shut
exit
!
router ospf 1
router-id 5.5.5.5
log-adjacency-changes
auto-cost reference-bandwidth 100000
passive-interface fastethernet0/0
!
line con 0
logging sync
no exec-timeout
!
end

!##################################################
!# Free CCNA Workbook Lab 9-X SW1 Initial Config #
!##################################################
!
enable
configure terminal
!
hostname SW1
no ip domain-lookup
!
line con 0
logging sync
no exec-timeout
!
end

Lab Objectives

  • Create 4 new loopback interfaces on R4 located in Area 44 using the ip addresses 10.44.4.0/24, 10.44.5.0/24, 10.44.6.0/24 and 10.44.7.0/24
  • Configure R4 to advertise a single Inter-Area summary route into the OSPF backbone that encompasses all 4 routes.
  • Verify that the summary route is being propagated correctly by viewing the routing table on R1.

Lab Instruction

Objective 1. – Create 4 new loopback interfaces on R4 located in Area 44 using the ip addresses 10.44.4.0/24, 10.44.5.0/24, 10.44.6.0/24 and 10.44.7.0/24

R4#configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
R4(config)#interface loopback4
R4(config-if)#
%LINEPROTO-5-UPDOWN: Line protocol on Interface Loopback4, changed state to up
R4(config-if)#ip add 10.44.4.1 255.255.255.0
R4(config-if)#ip ospf 1 area 44
R4(config-if)#interface loopback5
%LINEPROTO-5-UPDOWN: Line protocol on Interface Loopback5, changed state to up
R4(config-if)#ip add 10.44.5.1 255.255.255.0
R4(config-if)#ip ospf 1 area 44
R4(config-if)#interface loopback6
%LINEPROTO-5-UPDOWN: Line protocol on Interface Loopback6, changed state to up
R4(config-if)#ip add 10.44.6.1 255.255.255.0
R4(config-if)#ip ospf 1 area 44
R4(config-if)#interface loopback7
%LINEPROTO-5-UPDOWN: Line protocol on Interface Loopback7, changed state to up
R4(config-if)#ip add 10.44.7.1 255.255.255.0
R4(config-if)#ip ospf 1 area 44
R4(config-if)#end
R4#

<br>

Objective 2. – Configure R4 to advertise a single Inter-Area summary route into the OSPF backbone that encompasses all 4 routes.

R4#configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
R4(config)#router ospf 1
R4(config-router)#area 44 range 10.44.4.0 255.255.252.0
R4(config-router)#end
R4#
%SYS-5-CONFIG_I: Configured from console by console
R4#

Objective 3. – Verify that the summary route is being propagated correctly by viewing the routing table on R1.

R1#show ip route
Codes: 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
       * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

     10.0.0.0/8 is variably subnetted, 10 subnets, 5 masks
O IA    10.90.50.1/32 [110/64767] via 10.90.245.5, 00:43:29, Serial0/0
O IA    10.90.40.1/32 [110/64767] via 10.90.245.4, 00:43:29, Serial0/0
O IA    10.90.23.0/30 [110/129532] via 10.90.245.2, 00:43:29, Serial0/0
O IA    10.90.30.1/32 [110/129533] via 10.90.245.2, 00:43:29, Serial0/0
O IA    10.44.4.0/22 [110/64767] via 10.90.245.4, 00:00:57, Serial0/0
O IA    10.90.145..0/24 [110/65766] via 10.90.245.4, 00:43:29, Serial0/0
O IA    10.90.45.0/30 [110/129532] via 10.90.245.5, 00:43:29, Serial0/0
O IA    10.90.20.1/32 [110/64767] via 10.90.245.2, 00:43:29, Serial0/0
C       10.90.10.0/24 is directly connected, Loopback0
C       10.90.245.0/29 is directly connected, Serial0/0
R1#

Rate This Article

Thanks for reading: Configuring OSPF Route Summarization Tutorial, Sorry, my English is bad:)

Getting Info...

About the Author

I'm Aevon...Just a gal with an insane passion for all things cybersecurity. 17 years in the industry and still love what I'm doing.
#• Networking Fundamentals Tutorial • #• OSPF •

Post a Comment

Cookie Consent
We serve cookies on this site to analyze traffic, remember your preferences, and optimize your experience.
More Details
Oops!
It seems there is something wrong with your internet connection. Please connect to the internet and start browsing again.
AdBlock Detected!
We have detected that you are using adblocking plugin in your browser.
The revenue we earn by the advertisements is used to manage this website, we request you to whitelist our website in your adblocking plugin.
Site is Blocked
Sorry! This site is not available in your country.