Configuring EIGRP Route Summarization

In this lab you will learn how to configure an Enhanced Interior Gateway Routing Protocol (EIGRP) summary route to conserve router resources on upstream neighboring routers.

Real World Application & Core Knowledge

If you completed Lab 7-8 – Configuring RIP Route Summarization then you should have a basic understanding of how route summarization works. If you did not then to sum it all up; its basically the operation at which you subnet different subnets into a single larger subnet which gets advertised to neighboring routers to conserve router resources. For example, if you advertise a /22 subnet which encompasses four single /24 networks then you’re effectively cutting the resource requirements of neighboring routers by 75%; in which case an upstream router will have a single /22 route instead of four /24 routes to the same geographic location.

Configuring a summary address for EIGRP is done on a per interface basis uses practically the same command as configuring a summary address for RIP however there is a slight difference. When configuring a summary address on an interface for EIGRP you’ll use the ip summary-address eigrp AS# n.n.n.n s.s.s.s.s command whereas RIP uses the ip summary-address rip n.n.n.n s.s.s.s

Another benefit of using summary routes (aka: route aggregation) is if a single route goes down that is contained within a summary route, updates are not sent throughout the entire routed domain. Only the router advertising the summary route will know that the more specific route has went down. For EIGRP, this will prevent unwanted queries and potentially SIA in the EIGRP autonomous system.

In this lab you will configure four new loopback interfaces on R1 and configure a summary route on R1 advertised out the Frame-relay hub-and-spoke interface as well as the point-to-point interface towards R2.

Familiarize yourself with the following new command(s);

ip summary-address eigrp AS# n.n.n.n s.s.s.s.s – This command is executed in interface configuration mode to configure an EIGRP summary route to be advertised out a specific interface.

This lab will continue to build upon the topology previously used in Lab 8-7 and other labs found through out Section 8.

Lab Prerequisites

• If you just completed Lab 8-7 you may start where you left off, if not you can load the Free CCNA Workbook GNS3 topology; start and establish a console session with R1, R2, R3, R4 and R5 then load their initial configurations included below by copying the config from the textbox and pasting it into the routers console.

Initial Configurations

!################################################## !#  Free CCNA Workbook Lab 8-8 R1 Initial Config  # !################################################## ! enable configure terminal ! hostname R1 no ip domain-lookup ! interface Loopback0  description ### SIMULATED NETWORK ###  ip address 10.55.10.1 255.255.255.0 ! interface Serial1/0  description ### PHYSICAL FRAME RELAY INTERFACE ###  ip address 10.1.234.1 255.255.255.248  encapsulation frame-relay  serial restart-delay 0  no frame-relay inverse-arp  frame map ip 10.1.234.2 122 broadcast  frame map ip 10.1.234.3 123 broadcast  frame map ip 10.1.234.4 124  no ip split-horizon eigrp 10  no shut  exit ! router eigrp 10  no auto-summary  maximum-paths 1  network 10.1.234.1 0.0.0.0  network 10.55.10.1 0.0.0.0  neighbor 10.1.234.4 Serial1/0  neighbor 10.1.234.3 Serial1/0  neighbor 10.1.234.2 Serial1/0  exit ! line con 0  logging sync  no exec-timeout ! end

!################################################## !#  Free CCNA Workbook Lab 8-8 R2 Initial Config  # !################################################## ! enable configure terminal ! hostname R2 no ip domain-lookup ! interface Loopback0  description ### SIMULATED NETWORK ###  ip address 10.55.20.1 255.255.255.0 ! interface Serial1/0  description ### PHYSICAL FRAME RELAY INTERFACE ###  no ip address  encapsulation frame-relay  serial restart-delay 0  no frame-relay inverse-arp  no shut ! interface Serial1/0.221 point-to-point  description ### FRAME RELAY LINK TO R1 ###  ip address 10.1.234.2 255.255.255.248  frame-relay interface-dlci 221 ! interface Serial1/2  ### POINT-TO-POINT LINK TO R3 ###  ip add 10.0.23.1 255.255.255.252  encapsulation ppp  no shut  exit ! router eigrp 10  network 10.0.23.1 0.0.0.0  network 10.1.234.2 0.0.0.0  network 10.55.20.1 0.0.0.0  no auto-summary  neighbor 10.1.234.1 Serial1/0.221  exit ! line con 0  logging sync  no exec-timeout ! end

!################################################## !#  Free CCNA Workbook Lab 8-8 R3 Initial Config  # !################################################## ! enable configure terminal ! hostname R3 no ip domain-lookup ! interface Loopback0  description ### SIMULATED NETWORK ###  ip address 10.55.30.1 255.255.255.0 ! interface Serial1/0  description ### PHYSICAL FRAME RELAY INTERFACE ###  no ip address  encapsulation frame-relay  serial restart-delay 0  no frame-relay inverse-arp  no shut ! interface Serial1/0.321 point-to-point  description ### FRAME RELAY LINK TO R1 ###  ip address 10.1.234.3 255.255.255.248  frame-relay interface-dlci 321 ! interface Serial1/1  description ### POINT-TO-POINT LINK TO R2 ###  ip address 10.0.23.2 255.255.255.252  encapsulation ppp  no shut  exit ! router eigrp 10  network 10.0.23.2 0.0.0.0  network 10.1.234.3 0.0.0.0  network 10.55.30.1 0.0.0.0  no auto-summary  neighbor 10.1.234.1 Serial1/0.321  exit ! line con 0  logging sync  no exec-timeout ! end

!################################################## !#  Free CCNA Workbook Lab 8-8 R4 Initial Config  # !################################################## ! enable configure terminal ! hostname R4 no ip domain-lookup ! interface Loopback0  description ### SIMULATED NETWORK ###  ip address 10.55.40.1 255.255.255.0 ! interface Serial1/0  description ### PHYSICAL FRAME RELAY INTERFACE ###  ip address 10.1.234.4 255.255.255.248  ip hello-interval eigrp 10 5  ip hold-time eigrp 10 15  encapsulation frame-relay  serial restart-delay 0  no frame-relay inverse-arp  frame map ip 10.1.234.1 421  no shut ! interface Serial1/1  description ### POINT-TO-POINT LINK TO R5 ###  ip address 10.0.45.1 255.255.255.252  encapsulation ppp  no shut  exit ! router eigrp 10  network 10.0.45.1 0.0.0.0  network 10.1.234.4 0.0.0.0  network 10.55.40.1 0.0.0.0  no auto-summary  neighbor 10.1.234.1 Serial1/0  exit ! line con 0  logging sync  no exec-timeout ! end

!################################################## !#  Free CCNA Workbook Lab 8-8 R5 Initial Config  # !################################################## ! enable configure terminal ! hostname R5 no ip domain-lookup ! interface Loopback0  description ### SIMULATED NETWORK ###  ip address 10.55.50.1 255.255.255.0 ! interface Loopback5  description ### SIMULATED NETWORK ###  ip address 10.50.0.1 255.255.255.0 ! interface Serial1/1  description ### POINT-TO-POINT LINK TO R4 ###  ip address 10.0.45.2 255.255.255.252  encapsulation ppp  no shut  exit ! router eigrp 10  no auto-summary  eigrp stub  network 10.0.45.2 0.0.0.0  network 10.55.50.1 0.0.0.0  network 10.50.0.1 0.0.0.0  passive-interface Loopback5  exit ! line con 0  logging sync  no exec-timeout ! end

Lab Objectives

• Configure four new loopback interfaces on R1 using the numbers 4-7, configure these interfaces with the ip address range 10.122.4.0/22. Tip: The 3rd octet as the interface number.
• Configure a single network statement to encompass the four newly created loopback interfaces.
• On R1 configure a summary address of 10.122.4.0/22 to be advertised out both the frame-relay hub-and-spoke interface.
• Verify the summary address is being propagated correctly by viewing he routing table on R5.

Lab Instruction

Objective 1. – Configure four new loopback interfaces on R1 using the numbers 4-7, configure these interfaces with the ip address range 10.122.4.0/22. Tip: The 3rd octet as the interface number.

R1>enable R1#configure terminal Enter configuration commands, one per line. End with CNTL/Z. R1(config)#interface loopback4 %LINEPROTO-5-UPDOWN: Line protocol on Interface Loopback4, changed state to up R1(config-if)#ip add 10.122.4.1 255.255.255.0 R1(config-if)#interface loopback5 %LINEPROTO-5-UPDOWN: Line protocol on Interface Loopback5, changed state to up R1(config-if)#ip address 10.122.5.1 255.255.255.0 R1(config-if)#interface loopback6 %LINEPROTO-5-UPDOWN: Line protocol on Interface Loopback6, changed state to up R1(config-if)#ip add 10.122.6.1 255.255.255.0 R1(config-if)#interface loopback 7 %LINEPROTO-5-UPDOWN: Line protocol on Interface Loopback7, changed state to up R1(config-if)#ip add 10.122.7.1 255.255.255.0 R1(config-if)#exit R1(config)#

Objective 2. – Configure a single network statement to encompass the four newly created loopback interfaces.

R1(config)#router eigrp 10 R1(config-router)#network 10.122.4.0 0.0.3.255 R1(config-router)#exit R1(config)#

Objective 3. – On R1 configure a summary address of 10.122.4.0/22 to be advertised out both the frame-relay hub-and-spoke interface.

R1(config)#interface Serial1/0 R1(config-if)#ip summary-address eigrp 10 10.122.4.0 255.255.252.0 %DUAL-5-NBRCHANGE: IP-EIGRP(0) 10: Neighbor 10.1.234.4 (Serial1/0) is resync: summary configured %DUAL-5-NBRCHANGE: IP-EIGRP(0) 10: Neighbor 10.1.234.3 (Serial1/0) is resync: summary configured %DUAL-5-NBRCHANGE: IP-EIGRP(0) 10: Neighbor 10.1.234.2 (Serial1/0) is resync: summary configured R1(config-if)#end R1# %SYS-5-CONFIG_I: Configured from console by console R1#

Objective 4. – Verify the summary address is being propagated correctly by viewing he routing table on R5.

R5>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
     i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
     ia - IS-IS inter area, * - 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, 13 subnets, 5 masks
C       10.55.50.0/24 is directly connected, Loopback0
D       10.55.40.0/24 [90/2297856] via 10.0.45.1, 01:43:54, Serial1/1
D       10.0.23.1/32 [90/3705856] via 10.0.45.1, 01:43:54, Serial1/1
D       10.0.23.0/30 [90/3705856] via 10.0.45.1, 01:43:54, Serial1/1
D       10.0.23.2/32 [90/3705856] via 10.0.45.1, 01:43:54, Serial1/1
D       10.55.30.0/24 [90/3321856] via 10.0.45.1, 01:43:54, Serial1/1
C       10.0.45.1/32 is directly connected, Serial1/1
C       10.0.45.0/30 is directly connected, Serial1/1
D       10.55.20.0/24 [90/3321856] via 10.0.45.1, 01:43:54, Serial1/1
D       10.55.10.0/24 [90/2809856] via 10.0.45.1, 01:43:54, Serial1/1
C       10.50.0.0/24 is directly connected, Loopback5
D       10.122.4.0/22 [90/2809856] via 10.0.45.1, 00:05:37, Serial1/1
D       10.1.234.0/29 [90/2681856] via 10.0.45.1, 01:43:55, Serial1/1
R5>