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Showing posts from November, 2017

OSPF – stub area

This is second post about OSPF and today I will review how stub area behaves comparing to normal area (from previous post).





In this scenario R6, R7 and R8 can't reach R10's prefixes because LSA5 is not allowed withing a stub area.


R6#sh ip route       10.0.0.0/8 is variably subnetted, 6 subnets, 2 masks C        10.0.0.0/24 is directly connected, FastEthernet0/0 L        10.0.0.6/32 is directly connected, FastEthernet0/0 O IA     10.1.0.0/24 [110/2] via 10.0.0.7, 00:14:18, FastEthernet0/0 O IA     10.2.0.0/24 [110/3] via 10.0.0.7, 00:00:07, FastEthernet0/0 C        10.10.10.0/24 is directly connected, Loopback0 L        10.10.10.6/32 is directly connected, Loopback0 R6#sh ip ospf database database-summary             OSPF Router with ID (10.10.10.6) (Process ID 10) Area 0 database summary   LSA Type      Count    Delete   Maxage   Router        2        0        0   Network       1        0        0   Summary Net   2        0        0   Summary ASBR  0        0   …

OSPF – normal (non-backbone) area

I decided to review what I know about OSPF areas and what types of LSA are exchanged inside each type of areas. The first one is a normal area (not the backbone one). Over the next few posts I’m going to change area 1 type to see what is the difference.






Below you can see what I see on every router.


R6#sh ip route       10.0.0.0/8 is variably subnetted, 6 subnets, 2 masks C        10.0.0.0/24 is directly connected, FastEthernet0/0 L        10.0.0.6/32 is directly connected, FastEthernet0/0 O IA     10.1.0.0/24 [110/2] via 10.0.0.7, 03:17:09, FastEthernet0/0 O IA     10.2.0.0/24 [110/3] via 10.0.0.7, 02:41:26, FastEthernet0/0 C        10.10.10.0/24 is directly connected, Loopback0 L        10.10.10.6/32 is directly connected, Loopback0       172.16.0.0/24 is subnetted, 2 subnets O E2     172.16.3.0 [110/200] via 10.0.0.7, 02:41:26, FastEthernet0/0 O E2     172.16.4.0 [110/200] via 10.0.0.7, 02:41:26, FastEthernet0/0 R6# R6#sh ip ospf database database-summary             O…