EIGRP IPv4 - Stub
Stub
EIGRP (Enhanced Interior Gateway Routing Protocol) IPv4 Stub is a configuration option designed to enhance network efficiency by limiting the propagation of routing information in certain areas of the network. In a stub configuration, routers signal to their neighbors that they do not have paths to external networks. This reduces the volume of routing information exchanged and improves overall network stability. Additionally, routers in a stub area respond to queries for external routes with a default route, simplifying the routing tables of other routers in the network. EIGRP Stub is particularly useful in branch office or hub-and-spoke network topologies, where routers at the periphery may not require complete route information. By configuring EIGRP Stub, network administrators can streamline routing updates, optimize network resources, and enhance the scalability of the EIGRP routing protocol in specific areas of their network.
Lab:
Disclaimer
This Configuration Guide is designed to assist members to enhance their skills in particular technology area. While every effort has been made to ensure that all material is as complete and accurate as possible, the enclosed material is presented on an Dzas isdz basis. Neither the authors nor Forum assume any liability or responsibility to any person or entity with respect to loss or damages incurred from the information contained in this guide. This configuration guide was developed by Forum. Any similarities between material presented in this configuration guide and any other material is completely coincidental.
Cisco IOS Software, Linux Software (I86BI_LINUX-ADVENTERPRISEK9-M), Version 15.2(4)M1, DEVELOPMENT TEST SOFTWARE
Task 1: Configure EIGRP Stub
Step 1: In the configuration mode of router configure loopbacks with network address in sequence.
R1:
interface loopback 1
ip address 11.0.1.1 255.255.255.0
exit
interface loopback 2
ip address 11.0.2.1 255.255.255.0
exit
interface loopback 3
ip address 11.0.3.1 255.255.255.0
exit
Step 2: Configure EIGRP stub with connected option
R1:
router eigrp 100
eigrp stub ?
connected Do advertise connected routes
leak-map Allow dynamic prefixes based on the leak-map
receive-only Set receive only neighbor
redistributed Do advertise redistributed routes
static Do advertise static routes
summary Do advertise summary routes
eigrp stub connected
exit
EIGRP Stub router will do advertise its connected routes to the neighbor router.
Step 3: Configure EIGRP stub with connected static option
R1:
router eigrp 100
eigrp stub static
exit
EIGRP Stub router will do advertise static routes.
Step 4: Configure EIGRP stub with receive only option
R1:
router eigrp 100
eigrp stub receive-only
exit
EIGRP Stub router will only receive routes from its neighbor but will not advertise any routes to its neighbor.
Task 2: Verification:
Step 1: Verify route in neighbors router routing table by following command:
R2#show ip route
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
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, H - NHRP, l - LISP
+ - replicated route, % - next hop override
Gateway of last resort is not set
12.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 12.0.0.0/24 is directly connected, Serial2/0
L 12.0.0.2/32 is directly connected, Serial2/0
22.0.0.0/8 is variably subnetted, 6 subnets, 2 masks
C 22.0.1.0/24 is directly connected, Loopback1
L 22.0.1.2/32 is directly connected, Loopback1
C 22.0.2.0/24 is directly connected, Loopback2
L 22.0.2.2/32 is directly connected, Loopback2
C 22.0.3.0/24 is directly connected, Loopback3
L 22.0.3.2/32 is directly connected, Loopback3
23.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 23.0.0.0/24 is directly connected, Ethernet0/0
L 23.0.0.2/32 is directly connected, Ethernet0/0
33.0.0.0/24 is subnetted, 3 subnets
D 33.0.1.0 [90/409600] via 23.0.0.3, 01:39:35, Ethernet0/0
D 33.0.2.0 [90/409600] via 23.0.0.3, 01:39:35, Ethernet0/0
D 33.0.3.0 [90/409600] via 23.0.0.3, 01:39:35, Ethernet0/0
34.0.0.0/24 is subnetted, 1 subnets
D 34.0.0.0 [90/2195456] via 23.0.0.3, 01:39:32, Ethernet0/0
44.0.0.0/24 is subnetted, 3 subnets
D 44.0.1.0 [90/2323456] via 23.0.0.3, 01:39:35, Ethernet0/0
D 44.0.2.0 [90/2323456] via 23.0.0.3, 01:39:35, Ethernet0/0
D 44.0.3.0 [90/2323456] via 23.0.0.3, 01:39:35, Ethernet0/0
Router R2 will not receive 11 network from Stub router because Stub router will only receive and will not advertise its own 11 network to Router R2.
Step 2: Configure no auto summary and verify routes on neighbor router routing table
R1:
router eigrp 100
no auto-summary
exit
R2#show ip route
Codes: L - local, 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, H - NHRP, l - LISP
+ - replicated route, % - next hop override
Gateway of last resort is not set
12.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 12.0.0.0/24 is directly connected, Serial2/0
L 12.0.0.2/32 is directly connected, Serial2/0
22.0.0.0/8 is variably subnetted, 6 subnets, 2 masks
C 22.0.1.0/24 is directly connected, Loopback1
L 22.0.1.2/32 is directly connected, Loopback1
C 22.0.2.0/24 is directly connected, Loopback2
L 22.0.2.2/32 is directly connected, Loopback2
C 22.0.3.0/24 is directly connected, Loopback3
L 22.0.3.2/32 is directly connected, Loopback3
23.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 23.0.0.0/24 is directly connected, Ethernet0/0
L 23.0.0.2/32 is directly connected, Ethernet0/0
33.0.0.0/24 is subnetted, 3 subnets
D 33.0.1.0 [90/409600] via 23.0.0.3, 01:39:35, Ethernet0/0
D 33.0.2.0 [90/409600] via 23.0.0.3, 01:39:35, Ethernet0/0
D 33.0.3.0 [90/409600] via 23.0.0.3, 01:39:35, Ethernet0/0
34.0.0.0/24 is subnetted, 1 subnets
D 34.0.0.0 [90/2195456] via 23.0.0.3, 01:39:32, Ethernet0/0
44.0.0.0/24 is subnetted, 3 subnets
D 44.0.1.0 [90/2323456] via 23.0.0.3, 01:39:35, Ethernet0/0
D 44.0.2.0 [90/2323456] via 23.0.0.3, 01:39:35, Ethernet0/0
D 44.0.3.0 [90/2323456] via 23.0.0.3, 01:39:35, Ethernet0/0