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configure as below and make sure routing protocol running and working fine


R1

interface Loopback0
ip address 1.1.1.1 255.255.255.255


interface FastEthernet0/1
bandwidth 10000
ip address 192.168.1.1 255.255.255.0
duplex auto
speed auto


router eigrp 1
network 0.0.0.0
no auto-summary


R2
interface Loopback0
ip address 2.2.2.2 255.255.255.255

interface FastEthernet0/0
ip address 172.16.1.2 255.255.255.0
duplex auto
speed auto
!
interface FastEthernet0/1
bandwidth 10000
ip address 192.168.1.2 255.255.255.0
duplex auto
speed auto

router eigrp 1
network 0.0.0.0
no auto-summary


R3
interface Loopback0
ip address 3.3.3.3 255.255.255.255
!
interface FastEthernet0/0
ip address 172.16.1.3 255.255.255.0
duplex auto
speed auto
!
interface FastEthernet0/1
bandwidth 10000
ip address 192.168.1.3 255.255.255.0
duplex auto
speed auto
!
router eigrp 1
network 0.0.0.0
no auto-summary



if you notice, all interfaces inside network 192.168.1.0/24 are hard coded to be 10 000 kbps,

bandwidth 10000

this is because we want to simulate different kind of network (ie, frame-relay, ethernet, T1), to see how the bandwidth affect the matrix

show ip route from R2, you can only see one path to L0 on R3, this because routing table only show the best path to the destination

R2#sh ip rou
..

1.0.0.0/32 is subnetted, 1 subnets
D 1.1.1.1 [90/386560] via 192.168.1.1, 00:34:27, FastEthernet0/1
2.0.0.0/32 is subnetted, 1 subnets
C 2.2.2.2 is directly connected, Loopback0
3.0.0.0/32 is subnetted, 1 subnets
D 3.3.3.3 [90/156160] via 172.16.1.3, 00:34:27, FastEthernet0/0
172.16.0.0/24 is subnetted, 1 subnets
C 172.16.1.0 is directly connected, FastEthernet0/0
C 192.168.1.0/24 is directly connected, FastEthernet0/1

since Fa0/0 has speed of 100000kbps, so it should have a better matrix compare to Fa0/1 (we set it to 10000kbps), that's why we see path to 3.3.3.3 is via Fa0/0 (172.16.1.3) .

How to see all the possible path to the destination? issue show ip eigrp topology

R2#sh ip ei top
IP-EIGRP Topology Table for AS(1)/ID(2.2.2.2)

Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
r - reply Status, s - sia Status

P 1.1.1.1/32, 1 successors, FD is 386560
via 192.168.1.1 (386560/128256), FastEthernet0/1
P 3.3.3.3/32, 1 successors, FD is 156160
via 172.16.1.3 (156160/128256), FastEthernet0/0 successor (primary)
via 192.168.1.3 (386560/128256), FastEthernet0/1 feasible successor (backup)
P 2.2.2.2/32, 1 successors, FD is 128256
via Connected, Loopback0
P 192.168.1.0/24, 1 successors, FD is 258560
via Connected, FastEthernet0/1
P 172.16.1.0/24, 1 successors, FD is 28160
via Connected, FastEthernet0/0

you can see there's two path to 3.3.3.3, with two different FD (green),

what if we want to bring both of the path to the routing table to do the load balance? this can be achieve by using Variance , theoretically it is hard to explain but actually it is very easy to use

to achieve load balance, make sure variance(X) value is

X*[successor FD] > [feasible successor FD]

X > [386560]/[156160]

X > 2

so we'll take value that is greater than 2 for variance, we'll use 3
R2(config)#router eigrp 1
R2(config-router)#variance 3

show ip route to confirm load balance is working

R2#sh ip rou
..
1.0.0.0/32 is subnetted, 1 subnets
D 1.1.1.1 [90/386560] via 192.168.1.1, 00:03:01, FastEthernet0/1
2.0.0.0/32 is subnetted, 1 subnets
C 2.2.2.2 is directly connected, Loopback0
3.0.0.0/32 is subnetted, 1 subnets
D 3.3.3.3 [90/156160] via 172.16.1.3, 00:03:01, FastEthernet0/0
[90/386560] via 192.168.1.3, 00:03:01, FastEthernet0/1
172.16.0.0/24 is subnetted, 1 subnets
C 172.16.1.0 is directly connected, FastEthernet0/0
C 192.168.1.0/24 is directly connected, FastEthernet0/1

now all traffic destination to 3.3.3.3 is load balanced, un-equal load balance !!, traffic will be divided according to ratio of the matrix between the two route, in this case 2/1.

we can force this to have 50-50 or equal load balance, it's not a good practice but we still can do it

R2(config)#router eigrp 1
R2(config-router)#traffic-share balanced

just want to share with you another command that might be useful, show ip eigrp topology [address] [mask]

R2#sh ip ei top 3.3.3.3 255.255.255.255

IP-EIGRP (AS 1): Topology entry for 3.3.3.3/32
State is Passive, Query origin flag is 1, 1 Successor(s), FD is 156160
Routing Descriptor Blocks:
172.16.1.3 (FastEthernet0/0), from 172.16.1.3, Send flag is 0x0
Composite metric is (156160/128256), Route is Internal
Vector metric:
Minimum bandwidth is 100000 Kbit
Total delay is 5100 microseconds
Reliability is 255/255
Load is 1/255
Minimum MTU is 1500
Hop count is 1
192.168.1.3 (FastEthernet0/1), from 192.168.1.3, Send flag is 0x0
Composite metric is (386560/128256), Route is Internal
Vector metric:
Minimum bandwidth is 10000 Kbit
Total delay is 5100 microseconds
Reliability is 255/255
Load is 1/255
Minimum MTU is 1500
Hop count is 1