OSPF Manual Summarization:

After Configuring IP Addresses and routing protocols on all routers, configure route summarization on ABR (R2) and ASBR (R4).

Note: In OSPF manual summarization is done only on ABR and ASBR routers.

R2 (ABR):

Calculated summary route for loopbacks is 11.1.1.0/21

R2(config)#router ospf 1

R2(config-router)#area 10 range 11.1.1.0 255.255.248.0

Note: There is difference between ABR and ASBR route summarization commands

R4 (ASBR):

Calculated summary route for loopbacks is 14.1.1.0/21

R4(config)#router ospf 1

R4(config-router)#summary-address 14.1.1.0 255.255.248.0