we still use same network setup from the previous lab but with a little modification
remove area 50 and virtual link, advertise 50.50.50.x into area 20
R2
R2(config)#router os 1
R2(config-router)#no area 20 virtual-link 10.10.20.6
R6
R6(config)#router os 1
R6(config-router)#no area 20 virtual-link 172.16.2.1
R6(config-router)#no network 50.50.50.0 0.0.0.255 area 50
R6(config-router)#network 50.50.50.0 0.0.0.255 area 20
change area 20 to Stub area
R2
R2(config-router)#area 20 stub
R6
R6(config-router)#area 20 stub
3 Route type - O, O IA, O E1/E2
- O - route to a destination where the area is connected to it
R2 is connected to area 20(in yellow), area 0(in green)
show ip route
200.200.20.0/32 is subnetted, 1 subnets
O 200.200.20.1 [110/2] via 10.10.20.6, 00:03:56, FastEthernet0/0
50.0.0.0/32 is subnetted, 1 subnets
O 50.50.50.1 [110/2] via 10.10.20.6, 00:03:56, FastEthernet0/0
21.0.0.0/24 is subnetted, 1 subnets
O E2 21.21.21.0 [110/20] via 172.16.2.2, 00:03:56, Serial0/0
172.16.0.0/30 is subnetted, 3 subnets
O 172.16.1.0 [110/128] via 172.16.2.2, 00:04:43, Serial0/0
C 172.16.2.0 is directly connected, Serial0/0
O 172.16.3.0 [110/128] via 172.16.2.2, 00:04:43, Serial0/0
22.0.0.0/24 is subnetted, 1 subnets
O E2 22.22.22.0 [110/20] via 172.16.2.2, 00:03:56, Serial0/0
10.0.0.0/24 is subnetted, 2 subnets
C 10.10.20.0 is directly connected, FastEthernet0/0
O IA 10.40.1.0 [110/129] via 172.16.2.2, 00:03:57, Serial0/0
11.0.0.0/32 is subnetted, 1 subnets
O IA 11.11.11.1 [110/130] via 172.16.2.2, 00:03:57, Serial0/0
12.0.0.0/32 is subnetted, 1 subnets
O IA 12.12.12.1 [110/130] via 172.16.2.2, 00:03:57, Serial0/0
O E2 192.168.1.0/24 [110/20] via 172.16.2.2, 00:03:57, Serial0/0
- O IA - route to a destination in another OSPF area
from R2, area 40 suppose to be 'another area' for it, so, all the route to this destination should start with O IA
show ip route
200.200.20.0/32 is subnetted, 1 subnets
O 200.200.20.1 [110/2] via 10.10.20.6, 00:03:56, FastEthernet0/0
50.0.0.0/32 is subnetted, 1 subnets
O 50.50.50.1 [110/2] via 10.10.20.6, 00:03:56, FastEthernet0/0
21.0.0.0/24 is subnetted, 1 subnets
O E2 21.21.21.0 [110/20] via 172.16.2.2, 00:03:56, Serial0/0
172.16.0.0/30 is subnetted, 3 subnets
O 172.16.1.0 [110/128] via 172.16.2.2, 00:04:43, Serial0/0
C 172.16.2.0 is directly connected, Serial0/0
O 172.16.3.0 [110/128] via 172.16.2.2, 00:04:43, Serial0/0
22.0.0.0/24 is subnetted, 1 subnets
O E2 22.22.22.0 [110/20] via 172.16.2.2, 00:03:56, Serial0/0
10.0.0.0/24 is subnetted, 2 subnets
C 10.10.20.0 is directly connected, FastEthernet0/0
O IA 10.40.1.0 [110/129] via 172.16.2.2, 00:03:57, Serial0/0
11.0.0.0/32 is subnetted, 1 subnets
O IA 11.11.11.1 [110/130] via 172.16.2.2, 00:03:57, Serial0/0
12.0.0.0/32 is subnetted, 1 subnets
O IA 12.12.12.1 [110/130] via 172.16.2.2, 00:03:57, Serial0/0
O E2 192.168.1.0/24 [110/20] via 172.16.2.2, 00:03:57, Serial0/0
- O E2/E1 - External route that learned from redistribution
in this case all route that learned from RIP
show ip route
200.200.20.0/32 is subnetted, 1 subnets
O 200.200.20.1 [110/2] via 10.10.20.6, 00:03:56, FastEthernet0/0
50.0.0.0/32 is subnetted, 1 subnets
O 50.50.50.1 [110/2] via 10.10.20.6, 00:03:56, FastEthernet0/0
21.0.0.0/24 is subnetted, 1 subnets
O E2 21.21.21.0 [110/20] via 172.16.2.2, 00:03:56, Serial0/0
172.16.0.0/30 is subnetted, 3 subnets
O 172.16.1.0 [110/128] via 172.16.2.2, 00:04:43, Serial0/0
C 172.16.2.0 is directly connected, Serial0/0
O 172.16.3.0 [110/128] via 172.16.2.2, 00:04:43, Serial0/0
22.0.0.0/24 is subnetted, 1 subnets
O E2 22.22.22.0 [110/20] via 172.16.2.2, 00:03:56, Serial0/0
10.0.0.0/24 is subnetted, 2 subnets
C 10.10.20.0 is directly connected, FastEthernet0/0
O IA 10.40.1.0 [110/129] via 172.16.2.2, 00:03:57, Serial0/0
11.0.0.0/32 is subnetted, 1 subnets
O IA 11.11.11.1 [110/130] via 172.16.2.2, 00:03:57, Serial0/0
12.0.0.0/32 is subnetted, 1 subnets
O IA 12.12.12.1 [110/130] via 172.16.2.2, 00:03:57, Serial0/0
O E2 192.168.1.0/24 [110/20] via 172.16.2.2, 00:03:57, Serial0/0
4 Router type - Internal, Backbone, ABR and ASBR
show ip ospf can show all the information regarding to router type
- Internal - All interface in single area ; R0
check how many area it has
R0>sh ip os
Routing Process "ospf 1" with ID 172.16.3.2
...
Number of areas in this router is 1. 1 normal 0 stub 0 nssa
External flood list length 0
Area BACKBONE(0)
Number of interfaces in this area is 3
Area has no authentication
SPF algorithm last executed 00:43:05.116 ago
..
Number of DoNotAge LSA 4
Flood list length 0
- Backbone - at least one interface in area 0 ; R0, R1, R2 and R3
R1>sh ip os
Routing Process "ospf 1" with ID 172.16.1.1
Supports only single TOS(TOS0) routes
..
External flood list length 0
Area BACKBONE(0)
Number of interfaces in this area is 1
Area has no authentication
..
Number of DoNotAge LSA 4
Flood list length 0
Area 40
Number of interfaces in this area is 0
It is a stub area
..
Flood list length 0
- ABR - at least one interface in area 0, other interface interface in another area
- all ABR are Backbone ; R1, R2 and R3
- Backbone may be ABR, may not (where all interface in area 0); R0 is no ABR only because all int in area 0
R2>sh ip os
Routing Process "ospf 1" with ID 172.16.2.1
Supports only single TOS(TOS0) routes
Supports opaque LSA
Supports Link-local Signaling (LLS)
It is an area border router
..
- ASBR - where OSPF meet other routing protocol and perform route redistribution ; R1
R1>sh ip os
Routing Process "ospf 1" with ID 172.16.1.1
Supports only single TOS(TOS0) routes
Supports opaque LSA
Supports Link-local Signaling (LLS)
It is an autonomous system boundary router
Redistributing External Routes from,
rip, includes subnets in redistribution
Initial SPF schedule delay 5000 msecs
..
LSA type
use show ip ospf database
- LSA type 1 – Router LSAs are sent from a router to other routers in the same area. It contains information regarding the routers interfaces in the same area, relevant interfaces IPs, its adjacent routers on those interfaces and sub networks.
In this case, R2 have 2 area
R2>sh ip os da
OSPF Router with ID (172.16.2.1) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
172.16.1.1 172.16.1.1 1456 0x8000003C 0x00248A 2
172.16.2.1 172.16.2.1 1723 0x80000040 0x00297E 2
172.16.3.1 172.16.3.1 7 0x8000003B 0x004365 2
172.16.3.2 172.16.3.2 1756 0x80000042 0x003DB0 6
Summary Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
...
200.200.20.1 172.16.2.1 1461 0x80000002 0x007261
Router Link States (Area 20)
Link ID ADV Router Age Seq# Checksum Link count
10.10.20.6 10.10.20.6 1568 0x80000047 0x0018C2 3
172.16.2.1 172.16.2.1 1063 0x8000003F 0x009390 1
Net Link States (Area 20)
Link ID ADV Router Age Seq# Checksum
..
- LSA type 2 – Network LSAs are generated by the DR(on a broadcast network) on a multi access segment, and provides similar information to an LSA type 1 for the multi access segment and subnet which it belongs
in this broadcast 10.40.1.x only have 2 router, so R3 only show the other one on the database
R3>sh ip os da
OSPF Router with ID (172.16.3.1) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
172.16.1.1 172.16.1.1 1920 0x8000003C 0x00248A 2
..
172.16.3.1 172.16.3.1 232 0x80000040 0x0036D4 1
Net Link States (Area 40)
Link ID ADV Router Age Seq# Checksum
10.40.1.1 172.16.3.1 232 0x8000003B 0x00F91D
Summary Net Link States (Area 40)
Link ID ADV Router Age Seq# Checksum
0...
- LSA type 3 – Network Summary LSAs are generated by ABRs and contain the subnets & costs but omit the topological data from all subnets in one area and sent to another area via the ABR
R3>sh ip os da
OSPF Router with ID (172.16.3.1) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
172.16.1.1 172.16.1.1 261 0x8000003D 0x00228B 2
172.16.2.1 172.16.2.1 496 0x80000041 0x00277F 2
172.16.3.1 172.16.3.1 821 0x8000003B 0x004365 2
172.16.3.2 172.16.3.2 581 0x80000043 0x003BB1 6
Summary Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
10.10.20.0 172.16.2.1 243 0x80000046 0x008A84
10.40.1.0 172.16.3.1 575 0x80000046 0x00EB17
11.11.11.1 172.16.3.1 575 0x8000002B 0x00042A
12.12.12.1 172.16.3.1 575 0x8000002B 0x00DF4B
50.50.50.1 172.16.2.1 243 0x80000003 0x00D908
200.200.20.1 172.16.2.1 243 0x80000003 0x007062
Router Link States (Area 40)
..
- LSA type 4 -ASBR summary LSAs are from ASBRs and are identical in structure to a type 3 LSA and sent when crossing an AS boundary
somehow I can't show this information, still can't figure out where's the trick, but it should start with 'summary ASB link states'
- LSA type 5 -Are AS external LSAs which are originated by ASBRs and describe external networks
notice that the link ID are the one that learned from RIP
R2>sh ip os da
OSPF Router with ID (172.16.2.1) (Process ID 1)
...
Type-5 AS External Link States
Link ID ADV Router Age Seq# Checksum Tag
21.21.21.0 172.16.1.1 1616 0x8000003A 0x00DE8A 0
22.22.22.0 172.16.1.1 1621 0x8000003A 0x00BAAB 0
192.168.1.0 172.16.1.1 1621 0x8000003A 0x001925 0
and you not gonna see this type on Stub and Totally Stubby area, try 'show ip ospf database' on R5 and R6
for type 6 and type 7, i can't show in this network setup yet... will continue soon ;)
