Phase 2 is an Routing Protocol modification, here with EIGRP, split horizon is disabled which allows for the routes from the spokes to be propagated back out the tunnel to the other spokes.
IOS33#sh 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
a - application route
+ - replicated route, % - next hop override, p - overrides from PfR
Gateway of last resort is not set
10.0.0.0/24 is subnetted, 5 subnets
D 10.1.1.0
[90/26880256] via 172.16.103.24, 00:16:54, GigabitEthernet0/0
D 10.3.9.0
[90/26880768] via 172.16.103.24, 00:16:49, GigabitEthernet0/0
D 10.3.22.0
[90/26880512] via 172.16.103.24, 00:16:49, GigabitEthernet0/0
D 10.4.9.0
[90/26880768] via 172.16.103.24, 00:16:49, GigabitEthernet0/0
D 10.4.22.0
[90/26880512] via 172.16.103.24, 00:16:49, GigabitEthernet0/0
22.0.0.0/32 is subnetted, 1 subnets
D 22.22.22.22
[90/27008256] via 172.16.103.24, 00:16:49, GigabitEthernet0/0
24.0.0.0/32 is subnetted, 1 subnets
D 24.24.24.24
[90/130816] via 172.16.103.24, 22:24:49, GigabitEthernet0/0
33.0.0.0/32 is subnetted, 1 subnets
C 33.33.33.33 is directly connected, Loopback0
172.16.0.0/16 is variably subnetted, 3 subnets, 2 masks
D 172.16.101.0/24
[90/26880768] via 172.16.103.24, 00:16:49, GigabitEthernet0/0
C 172.16.103.0/24 is directly connected, GigabitEthernet0/0
L 172.16.103.33/32 is directly connected, GigabitEthernet0/0
IOS22
interface Tunnel1
no ip split-horizon eigrp 1
%DUAL-5-NBRCHANGE: EIGRP-IPv4 1: Neighbor 10.1.1.24 (Tunnel1) is resync: split horizon changed
%DUAL-5-NBRCHANGE: EIGRP-IPv4 1: Neighbor 10.1.1.11 (Tunnel1) is resync: split horizon changed
%DUAL-5-NBRCHANGE: EIGRP-IPv4 1: Neighbor 10.1.1.25 (Tunnel1) is resync: split horizon changed
IOS33#sh ip route eigrp
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
a - application route
+ - replicated route, % - next hop override, p - overrides from PfR
Gateway of last resort is not set
10.0.0.0/24 is subnetted, 9 subnets
D 10.1.1.0
[90/26880256] via 172.16.103.24, 00:18:59, GigabitEthernet0/0
D 10.3.9.0
[90/26880768] via 172.16.103.24, 00:18:54, GigabitEthernet0/0
D 10.3.22.0
[90/26880512] via 172.16.103.24, 00:18:54, GigabitEthernet0/0
D 10.4.9.0
[90/26880768] via 172.16.103.24, 00:18:54, GigabitEthernet0/0
D 10.4.22.0
[90/26880512] via 172.16.103.24, 00:18:54, GigabitEthernet0/0
D 10.11.19.0
[90/28160512] via 172.16.103.24, 00:00:49, GigabitEthernet0/0
D EX 10.102.12.0
[170/28160768] via 172.16.103.24, 00:00:49, GigabitEthernet0/0
D EX 10.102.15.0
[170/28160768] via 172.16.103.24, 00:00:49, GigabitEthernet0/0
D EX 10.102.25.0
[170/28160512] via 172.16.103.24, 00:00:49, GigabitEthernet0/0
19.0.0.0/32 is subnetted, 1 subnets
D 19.19.19.19
[90/28288512] via 172.16.103.24, 00:00:49, GigabitEthernet0/0
20.0.0.0/32 is subnetted, 1 subnets
D EX 20.20.20.20
[170/28288512] via 172.16.103.24, 00:00:49, GigabitEthernet0/0
22.0.0.0/32 is subnetted, 1 subnets
D 22.22.22.22
[90/27008256] via 172.16.103.24, 00:18:54, GigabitEthernet0/0
24.0.0.0/32 is subnetted, 1 subnets
D 24.24.24.24
[90/130816] via 172.16.103.24, 22:26:54, GigabitEthernet0/0
172.16.0.0/16 is variably subnetted, 3 subnets, 2 masks
D 172.16.101.0/24
[90/26880768] via 172.16.103.24, 00:18:54, GigabitEthernet0/0
IOS33#traceroute 20.20.20.20 source loopback 0 num
Type escape sequence to abort.
Tracing the route to 20.20.20.20
VRF info: (vrf in name/id, vrf out name/id)
1 172.16.103.24 22 msec 14 msec 11 msec
2 10.1.1.22 31 msec 25 msec 22 msec
3 10.1.1.25 49 msec 42 msec 44 msec
4 20.20.20.20 57 msec 44 msec 36 msec
IOS33#sh 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
a - application route
+ - replicated route, % - next hop override, p - overrides from PfR
Gateway of last resort is not set
10.0.0.0/24 is subnetted, 5 subnets
D 10.1.1.0
[90/26880256] via 172.16.103.24, 00:16:54, GigabitEthernet0/0
D 10.3.9.0
[90/26880768] via 172.16.103.24, 00:16:49, GigabitEthernet0/0
D 10.3.22.0
[90/26880512] via 172.16.103.24, 00:16:49, GigabitEthernet0/0
D 10.4.9.0
[90/26880768] via 172.16.103.24, 00:16:49, GigabitEthernet0/0
D 10.4.22.0
[90/26880512] via 172.16.103.24, 00:16:49, GigabitEthernet0/0
22.0.0.0/32 is subnetted, 1 subnets
D 22.22.22.22
[90/27008256] via 172.16.103.24, 00:16:49, GigabitEthernet0/0
24.0.0.0/32 is subnetted, 1 subnets
D 24.24.24.24
[90/130816] via 172.16.103.24, 22:24:49, GigabitEthernet0/0
33.0.0.0/32 is subnetted, 1 subnets
C 33.33.33.33 is directly connected, Loopback0
172.16.0.0/16 is variably subnetted, 3 subnets, 2 masks
D 172.16.101.0/24
[90/26880768] via 172.16.103.24, 00:16:49, GigabitEthernet0/0
C 172.16.103.0/24 is directly connected, GigabitEthernet0/0
L 172.16.103.33/32 is directly connected, GigabitEthernet0/0
IOS22
interface Tunnel1
no ip split-horizon eigrp 1
%DUAL-5-NBRCHANGE: EIGRP-IPv4 1: Neighbor 10.1.1.24 (Tunnel1) is resync: split horizon changed
%DUAL-5-NBRCHANGE: EIGRP-IPv4 1: Neighbor 10.1.1.11 (Tunnel1) is resync: split horizon changed
%DUAL-5-NBRCHANGE: EIGRP-IPv4 1: Neighbor 10.1.1.25 (Tunnel1) is resync: split horizon changed
IOS33#sh ip route eigrp
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
a - application route
+ - replicated route, % - next hop override, p - overrides from PfR
Gateway of last resort is not set
10.0.0.0/24 is subnetted, 9 subnets
D 10.1.1.0
[90/26880256] via 172.16.103.24, 00:18:59, GigabitEthernet0/0
D 10.3.9.0
[90/26880768] via 172.16.103.24, 00:18:54, GigabitEthernet0/0
D 10.3.22.0
[90/26880512] via 172.16.103.24, 00:18:54, GigabitEthernet0/0
D 10.4.9.0
[90/26880768] via 172.16.103.24, 00:18:54, GigabitEthernet0/0
D 10.4.22.0
[90/26880512] via 172.16.103.24, 00:18:54, GigabitEthernet0/0
D 10.11.19.0
[90/28160512] via 172.16.103.24, 00:00:49, GigabitEthernet0/0
D EX 10.102.12.0
[170/28160768] via 172.16.103.24, 00:00:49, GigabitEthernet0/0
D EX 10.102.15.0
[170/28160768] via 172.16.103.24, 00:00:49, GigabitEthernet0/0
D EX 10.102.25.0
[170/28160512] via 172.16.103.24, 00:00:49, GigabitEthernet0/0
19.0.0.0/32 is subnetted, 1 subnets
D 19.19.19.19
[90/28288512] via 172.16.103.24, 00:00:49, GigabitEthernet0/0
20.0.0.0/32 is subnetted, 1 subnets
D EX 20.20.20.20
[170/28288512] via 172.16.103.24, 00:00:49, GigabitEthernet0/0
22.0.0.0/32 is subnetted, 1 subnets
D 22.22.22.22
[90/27008256] via 172.16.103.24, 00:18:54, GigabitEthernet0/0
24.0.0.0/32 is subnetted, 1 subnets
D 24.24.24.24
[90/130816] via 172.16.103.24, 22:26:54, GigabitEthernet0/0
172.16.0.0/16 is variably subnetted, 3 subnets, 2 masks
D 172.16.101.0/24
[90/26880768] via 172.16.103.24, 00:18:54, GigabitEthernet0/0
IOS33#traceroute 20.20.20.20 source loopback 0 num
Type escape sequence to abort.
Tracing the route to 20.20.20.20
VRF info: (vrf in name/id, vrf out name/id)
1 172.16.103.24 22 msec 14 msec 11 msec
2 10.1.1.22 31 msec 25 msec 22 msec
3 10.1.1.25 49 msec 42 msec 44 msec
4 20.20.20.20 57 msec 44 msec 36 msec
