Thursday, November 30, 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        0

  Type-7 Ext    0        0        0

    Prefixes redistributed in Type-7  0

  Opaque Link   0        0        0

  Opaque Area   0        0        0

  Subtotal      5        0        0

Process 10 database summary

  LSA Type      Count    Delete   Maxage

  Router        2        0        0

  Network       1        0        0

  Summary Net   2        0        0

  Summary ASBR  0        0        0

  Type-7 Ext    0        0        0

  Opaque Link   0        0        0

  Opaque Area   0        0        0

  Type-5 Ext    0        0        0

      Prefixes redistributed in Type-5  0

  Opaque AS     0        0        0

  Non-self      3

  Total         5        0        0

R6#


R7#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        10.0.0.7/32 is directly connected, FastEthernet0/0

C        10.1.0.0/24 is directly connected, FastEthernet1/0

L        10.1.0.7/32 is directly connected, FastEthernet1/0

O        10.2.0.0/24 [110/2] via 10.1.0.8, 00:01:24, FastEthernet1/0

O        10.10.10.6/32 [110/2] via 10.0.0.6, 00:04:48, FastEthernet0/0

R7#sh ip ospf database database-summary

            OSPF Router with ID (10.1.0.7) (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        0

  Type-7 Ext    0        0        0

    Prefixes redistributed in Type-7  0

  Opaque Link   0        0        0

  Opaque Area   0        0        0

  Subtotal      5        0        0

Area 1 database summary

  LSA Type      Count    Delete   Maxage

  Router        3        0        0

  Network       2        0        0

  Summary Net   3        0        0

  Summary ASBR  0        0        0

  Type-7 Ext    0        0        0

    Prefixes redistributed in Type-7  0

  Opaque Link   0        0        0

  Opaque Area   0        0        0

  Subtotal      8        0        0

Process 10 database summary

  LSA Type      Count    Delete   Maxage

  Router        5        0        0

  Network       3        0        0

  Summary Net   5        0        0

  Summary ASBR  0        0        0

  Type-7 Ext    0        0        0

  Opaque Link   0        0        0

  Opaque Area   0        0        0

  Type-5 Ext    0        0        0

      Prefixes redistributed in Type-5  0

  Opaque AS     0        0        0

  Non-self      6

  Total         13       0        0

R7#


R8#sh ip route

Gateway of last resort is 10.1.0.7 to network 0.0.0.0

O*IA  0.0.0.0/0 [110/2] via 10.1.0.7, 00:04:20, FastEthernet1/0

      10.0.0.0/8 is variably subnetted, 6 subnets, 2 masks

O IA     10.0.0.0/24 [110/2] via 10.1.0.7, 00:04:20, FastEthernet1/0

C        10.1.0.0/24 is directly connected, FastEthernet1/0

L        10.1.0.8/32 is directly connected, FastEthernet1/0

C        10.2.0.0/24 is directly connected, FastEthernet0/0

L        10.2.0.8/32 is directly connected, FastEthernet0/0

O IA     10.10.10.6/32 [110/3] via 10.1.0.7, 00:04:20, FastEthernet1/0

R8#sh ip ospf database database-summary

            OSPF Router with ID (10.2.0.8) (Process ID 10)

Area 1 database summary

  LSA Type      Count    Delete   Maxage

  Router        3        0        0

  Network       2        0        0

  Summary Net   3        0        0

  Summary ASBR  0        0        0

  Type-7 Ext    0        0        0

    Prefixes redistributed in Type-7  0

  Opaque Link   0        0        0

  Opaque Area   0        0        0

  Subtotal      8        0        0

Process 10 database summary

  LSA Type      Count    Delete   Maxage

  Router        3        0        0

  Network       2        0        0

  Summary Net   3        0        0

  Summary ASBR  0        0        0

  Type-7 Ext    0        0        0

  Opaque Link   0        0        0

  Opaque Area   0        0        0

  Type-5 Ext    0        0        0

      Prefixes redistributed in Type-5  0

  Opaque AS     0        0        0

  Non-self      6

  Total         8        0        0

R8#


R9#sh ip route

Gateway of last resort is 10.2.0.8 to network 0.0.0.0

O*IA  0.0.0.0/0 [110/3] via 10.2.0.8, 00:05:20, FastEthernet0/0

      10.0.0.0/8 is variably subnetted, 5 subnets, 2 masks

O IA     10.0.0.0/24 [110/3] via 10.2.0.8, 00:05:20, FastEthernet0/0

O        10.1.0.0/24 [110/2] via 10.2.0.8, 00:05:30, FastEthernet0/0

C        10.2.0.0/24 is directly connected, FastEthernet0/0

L        10.2.0.9/32 is directly connected, FastEthernet0/0

O IA     10.10.10.6/32 [110/4] via 10.2.0.8, 00:05:20, FastEthernet0/0

      172.16.0.0/16 is variably subnetted, 3 subnets, 2 masks

C        172.16.3.0/24 is directly connected, FastEthernet1/1

L        172.16.3.9/32 is directly connected, FastEthernet1/1

R        172.16.4.0/24 [120/1] via 172.16.3.10, 00:00:07, FastEthernet1/1

R9#sh ip ospf database database-summary

            OSPF Router with ID (172.16.3.9) (Process ID 10)

Area 1 database summary

  LSA Type      Count    Delete   Maxage

  Router        3        0        0

  Network       2        0        0

  Summary Net   3        0        0

  Summary ASBR  0        0        0

  Type-7 Ext    0        0        0

    Prefixes redistributed in Type-7  0

  Opaque Link   0        0        0

  Opaque Area   0        0        0

  Subtotal      8        0        0

Process 10 database summary

  LSA Type      Count    Delete   Maxage

  Router        3        0        0

  Network       2        0        0

  Summary Net   3        0        0

  Summary ASBR  0        0        0

  Type-7 Ext    0        0        0

  Opaque Link   0        0        0

  Opaque Area   0        0        0

  Type-5 Ext    0        0        0

      Prefixes redistributed in Type-5  0

  Opaque AS     0        0        0

  Non-self      6

  Total         8        0        0

R9#

R10#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

       + - replicated route, % - next hop override

Gateway of last resort is not set

S     10.0.0.0/8 [1/0] via 172.16.3.9

      172.16.0.0/16 is variably subnetted, 4 subnets, 2 masks

C        172.16.3.0/24 is directly connected, FastEthernet1/1

L        172.16.3.10/32 is directly connected, FastEthernet1/1

C        172.16.4.0/24 is directly connected, Loopback0

L        172.16.4.10/32 is directly connected, Loopback0

R10# 
 
 
 
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