Posted by: Barly Wicaksono | 9 January, 2013

OSPF Stub Area di Juniper

Basic Knowlegde

Stub areas are areas through which or into which AS external advertisements are not flooded. You might want to create stub areas when much of the topological database consists of AS external advertisements. Doing so reduces the size of the topological databases and therefore the amount of memory required on the internal routers in the stub area.

Routing devices within a stub area rely on the default routes originated by the area’s ABR to reach external AS destinations. You must configure thedefault-metric option on the ABR before it advertises a default route. Once configured, the ABR advertises a default route in place of the external routes that are not being advertised within the stub area, so that routing devices in the stub area can reach destinations outside the area.

The following restrictions apply to stub areas: you cannot create a virtual link through a stub area, a stub area cannot contain an AS boundary router, the backbone cannot be a stub area, and you cannot configure an area as both a stub area and a not-so-stubby area. (Sumber)

Question :
If i want to set area 10 as a stub area, which router should i configure?

Answer :
You have to configure ABR Router and ASBR Router within the Area 10

Stub Area

Stub Area

.

Konfigurasi Router

- Logical Router Jakarta -
set logical-routers Jakarta interfaces em0 unit 0 vlan-id 10
set logical-routers Jakarta interfaces em0 unit 0 family inet address 192.168.0.1/30
set logical-routers Jakarta interfaces lo0 unit 0 family inet address 1.1.1.1/32
set logical-routers Jakarta protocols ospf area 0.0.0.10 interface all

- Logical Router Bandung -
set logical-routers Bandung interfaces em1 unit 0 vlan-id 10
set logical-routers Bandung interfaces em1 unit 0 family inet address 192.168.0.2/30
set logical-routers Bandung interfaces em1 unit 1 vlan-id 20
set logical-routers Bandung interfaces em1 unit 1 family inet address 192.168.10.2/30
set logical-routers Bandung interfaces lo0 unit 1 family inet address 2.2.2.2/32
set logical-routers Bandung protocols ospf area 0.0.0.0 interface em1.1
set logical-routers Bandung protocols ospf area 0.0.0.0 interface lo0.1
set logical-routers Bandung protocols ospf area 0.0.0.10 interface em1.0

- Logical Router Semarang -
set logical-routers Semarang interfaces em2 unit 0 vlan-id 30
set logical-routers Semarang interfaces em2 unit 0 family inet address 192.168.20.2/30
set logical-routers Semarang interfaces em2 unit 1 vlan-id 20
set logical-routers Semarang interfaces em2 unit 1 family inet address 192.168.10.1/30
set logical-routers Semarang interfaces lo0 unit 2 family inet address 3.3.3.3/32
set logical-routers Semarang protocols ospf area 0.0.0.0 interface em2.1
set logical-routers Semarang protocols ospf area 0.0.0.0 interface lo0.2
set logical-routers Semarang protocols ospf area 0.0.0.20 interface em2.0

- Logical Router Surabaya -
set logical-routers Surabaya interfaces em3 unit 0 vlan-id 30
set logical-routers Surabaya interfaces em3 unit 0 family inet address 192.168.20.1/30
set logical-routers Surabaya interfaces lo0 unit 3 family inet address 4.4.4.4/32
set logical-routers Surabaya protocols ospf area 0.0.0.20 interface all
-----------------------------------------------------------------------------------------

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Konfigurasi Stub Area

- Logical Router Jakarta -
set logical-routers Jakarta protocols ospf area 0.0.0.10 stub

- Logical Router Bandung -
set logical-routers Bandung protocols ospf area 0.0.0.10 stub default-metric 10
-----------------------------------------------------------------------------------------

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Verification

- Logical Router Jakarta (BEFORE) -
[edit]
barly# run show ospf database logical-router Jakarta

OSPF link state database, Area 0.0.0.10
Type       ID               Adv Rtr           Seq      Age  Opt  Cksum  Len
Router  *1.1.1.1          1.1.1.1          0x80000006    25  0x22 0x2a13  48
Router   2.2.2.2          2.2.2.2          0x80000003    26  0x22 0x3317  36
Network *192.168.0.1      1.1.1.1          0x80000001    25  0x22 0x3a88  32
Summary  2.2.2.2          2.2.2.2          0x80000001    26  0x22 0xf03c  28
Summary  3.3.3.3          2.2.2.2          0x80000001    26  0x22 0xcc5b  28
Summary  4.4.4.4          2.2.2.2          0x80000001    26  0x22 0xa87a  28
Summary  192.168.10.0     2.2.2.2          0x80000001    26  0x22 0x259e  28
Summary  192.168.20.0     2.2.2.2          0x80000001    26  0x22 0xc0f7  28

- Logical Router Bandung (BEFORE) -
[edit]
barly# run show ospf database logical-router Bandung

OSPF link state database, Area 0.0.0.0
Type       ID               Adv Rtr           Seq      Age  Opt  Cksum  Len
Router  *2.2.2.2          2.2.2.2          0x8000000b   122  0x22 0x1402  48
Router   3.3.3.3          3.3.3.3          0x8000000b   123  0x22 0xcfe   48
Network  192.168.10.1     3.3.3.3          0x80000007   478  0x22 0xc7da  32
Summary *1.1.1.1          2.2.2.2          0x80000001   122  0x22 0x2907  28
Summary  4.4.4.4          3.3.3.3          0x80000008   123  0x22 0x72a6  28
Summary *192.168.0.0      2.2.2.2          0x80000002   122  0x22 0x913b  28
Summary  192.168.20.0     3.3.3.3          0x80000009   123  0x22 0x8825  28

OSPF link state database, Area 0.0.0.10
Type       ID               Adv Rtr           Seq      Age  Opt  Cksum  Len
Router   1.1.1.1          1.1.1.1          0x80000006   123  0x22 0x2a13  48
Router  *2.2.2.2          2.2.2.2          0x80000003   122  0x22 0x3317  36
Network  192.168.0.1      1.1.1.1          0x80000001   123  0x22 0x3a88  32
Summary *2.2.2.2          2.2.2.2          0x80000001   122  0x22 0xf03c  28
Summary *3.3.3.3          2.2.2.2          0x80000001   122  0x22 0xcc5b  28
Summary *4.4.4.4          2.2.2.2          0x80000001   122  0x22 0xa87a  28
Summary *192.168.10.0     2.2.2.2          0x80000001   122  0x22 0x259e  28
Summary *192.168.20.0     2.2.2.2          0x80000001   122  0x22 0xc0f7  28
-----------------------------------------------------------------------------------------
- Logical Router Jakarta (After) -
[edit]
barly# run show ospf database logical-router Jakarta

OSPF link state database, Area 0.0.0.10
Type       ID               Adv Rtr           Seq      Age  Opt  Cksum  Len
Router  *1.1.1.1          1.1.1.1          0x80000003    98  0x20 0x58e8  48
Router   2.2.2.2          2.2.2.2          0x80000003   100  0x20 0x5bef  36
Network  192.168.0.2      2.2.2.2          0x80000002   100  0x20 0x1ea0  32
Summary  0.0.0.0          2.2.2.2          0x80000001   144  0x20 0xcf5d  28
Summary  2.2.2.2          2.2.2.2          0x80000001   144  0x20 0xf20   28
Summary  3.3.3.3          2.2.2.2          0x80000001   144  0x20 0xea3f  28
Summary  4.4.4.4          2.2.2.2          0x80000001   144  0x20 0xc65e  28
Summary  192.168.10.0     2.2.2.2          0x80000001   144  0x20 0x4382  28
Summary  192.168.20.0     2.2.2.2          0x80000001   144  0x20 0xdedb  28

- Logical Router Bandung (After) -
[edit]
barly# run show ospf database logical-router Bandung

OSPF link state database, Area 0.0.0.0
Type       ID               Adv Rtr           Seq      Age  Opt  Cksum  Len
Router  *2.2.2.2          2.2.2.2          0x8000000d   146  0x22 0x1004  48
Router   3.3.3.3          3.3.3.3          0x8000000d   147  0x22 0x801   48
Network  192.168.10.1     3.3.3.3          0x80000008  1438  0x22 0xc5db  32
Summary *1.1.1.1          2.2.2.2          0x80000001   101  0x22 0x2907  28
Summary  4.4.4.4          3.3.3.3          0x8000000a   147  0x22 0x6ea8  28
Summary *192.168.0.0      2.2.2.2          0x80000004   101  0x22 0x8d3d  28
Summary  192.168.20.0     3.3.3.3          0x8000000b   147  0x22 0x8427  28

OSPF link state database, Area 0.0.0.10
Type       ID               Adv Rtr           Seq      Age  Opt  Cksum  Len
Router   1.1.1.1          1.1.1.1          0x80000003   102  0x20 0x58e8  48
Router  *2.2.2.2          2.2.2.2          0x80000003   102  0x20 0x5bef  36
Network *192.168.0.2      2.2.2.2          0x80000002   102  0x20 0x1ea0  32
Summary *0.0.0.0          2.2.2.2          0x80000001   146  0x20 0xcf5d  28
Summary *2.2.2.2          2.2.2.2          0x80000001   146  0x20 0xf20   28
Summary *3.3.3.3          2.2.2.2          0x80000001   146  0x20 0xea3f  28
Summary *4.4.4.4          2.2.2.2          0x80000001   146  0x20 0xc65e  28
Summary *192.168.10.0     2.2.2.2          0x80000001   146  0x20 0x4382  28
Summary *192.168.20.0     2.2.2.2          0x80000001   146  0x20 0xdedb  28
-----------------------------------------------------------------------------------------

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