OSPF Routers Connected by an Unnumbered Serial Link

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　　Router 1.1.1.1


Current configuration:
hostname r1.1.1.1
interface Loopback0
ip address 1.1.1.1 255.0.0.0
interface Ethernet2/0/0
ip address 4.0.0.1 255.0.0.0
interface Serial2/1/0
ip unnumbered Ethernet2/0/0
router ospf 1
network 4.0.0.0 0.255.255.255 area 0
end
　　


　　Router 2.2.2.2


Current configuration:
hostname r2.2.2.2
interface Loopback0
ip address 2.2.2.2 255.0.0.0
interface Ethernet0/0/4
ip address 6.0.0.2 255.0.0.0
interface Serial2/1/0
ip unnumbered Ethernet0/0/4
router ospf 2
network 6.0.0.0 0.255.255.255 area 0
end
r2.2.2.2#show ip ospf database
OSPF Router with ID (2.2.2.2) (Process ID 2)
Router Link States (Area 0)
Link ID   ADV Router  Age   Seq#           Checksum     Link count
1.1.1.1   1.1.1.1     254   0x8000001A     0xA6FA           2
2.2.2.2   2.2.2.2     253   0x80000017     0x4858           2
r2.2.2.2#show ip ospf database router 1.1.1.1
OSPF Router with ID (2.2.2.2) (Process ID 2)
Router Link States (Area 0)
LS age: 279
Options: (No TOS-capability, DC)
LS Type: Router Links
Link State ID: 1.1.1.1   

!--- For router links, Link State Id is always the same as the
!--- Advertising Router (next line).

Advertising Router: 1.1.1.1

!--- This is the router ID of the router which created
!--- this LSA.

LS Seq Number: 8000001A
Checksum: 0xA6FA
Length: 48
Number of Links: 2
Link connected to: another Router (point-to-point)

!--- This line shows that this router (1.1.1.1) is a neighbor
!--- with 2.2.2.2.

(Link ID) Neighboring Router ID: 2.2.2.2
(Link Data) Router Interface address: 0.0.0.12

!--- In the case of unnumbered link, use the MIB II IfIndex  
!--- value. This value usually starts with 0.

Number of TOS metrics: 0
TOS 0 Metrics: 64

!--- This is the OSPF cost of the link that connects
!--- the two routers.

Link connected to: a Stub Network

!--- This entry represents the Ethernet segment 4.0.0.0/8.

(Link ID) Network/subnet number: 4.0.0.0
(Link Data) Network Mask: 255.0.0.0
Number of TOS metrics: 0
TOS 0 Metrics: 10  

!--- This is the OSPF cost of the Ethernet segment.

r2.2.2.2#show ip ospf database router 2.2.2.2
OSPF Router with ID (2.2.2.2) (Process ID 2)
Router Link States (Area 0)
LS age: 295
Options: (No TOS-capability, DC)
LS Type: Router Links
Link State ID: 2.2.2.2
Advertising Router: 2.2.2.2
LS Seq Number: 80000017
Checksum: 0x4858
Length: 48
Number of Links: 2
Link connected to: another Router (point-to-point)
(Link ID) Neighboring Router ID: 1.1.1.1
(Link Data) Router Interface address: 0.0.0.10
Number of TOS metrics: 0
TOS 0 Metrics: 64
Link connected to: a Stub Network
(Link ID) Network/subnet number: 6.0.0.0
(Link Data) Network Mask: 255.0.0.0
Number of TOS metrics: 0
TOS 0 Metrics: 10