The show ip ospf neighbor Command

show ip ospf neighbor [type number] [neighbor-id] [detail]

This command is used to show OSPF neighbors. All the neighbors known to the router may be viewed, or the command can be made more granular and the neighbors can be shown on a perinterface basis. One neighbor also may be picked out for scrutiny. This level of detail is excellent for troubleshooting configuration errors.

Example 5-9 shows the output of this command. Table 5-11 explains how to read this information.

Example 5-9 show ip ospf neighbor Output

SanJose#show ip

ospf

neighbor

Neighbor ID

Pri

State

Dead Time

Address

Interface

140.100.17.132

1

FULL/DROTHER

00

00

36

140

100

17.

132

FastEthernet1/0

140.100.17.131

1

FULL/DROTHER

00

00

37

140

100

17.

131

FastEthernet1/0

140.100.23.1

1

FULL/BDR

00

00

38

140

100

17.

130

FastEthernet1/0

140.100.32.12

1

FULL/DROTHER

00

00

35

140

100

32

12

Fddi2/0

140.100.32.11

1

FULL/DR

00

00

32

140

100

32

11

Fddi2/0

140.100.17.194

1

FULL/DR

00

00

31

140

100

17.

194

FastEthernet3/0

To be more specific, in what is viewed, it is possible to look at the neighbors that have been discovered on a particular interface, as seen in Example 5-10.

Example 5-10 The Neighbors That Have Been Discovered on a Particular Interface

SanJose#show ip

ospf

neighbor fddi

2/0

Neighbor ID

Pri

State

Dead Time

Address

Interface

140.100.32.12

1

FULL/DROTHER

00:00:36

140.100

32

12

Fddi2/0

140.100.32.11

1

FULL/DR

00:00:32

140.100

32

11

Fddi2/0

To see all the neighbors in as much detail as possible, however, use the command displayed in Example 5-11.

Example 5-11 Using the show ip ospf neighbor detail Command

SanJose#show ip ospf neighbor detail

Neighbor 140.100.17.132, interface address 140.100.17.132 In the area 3 via interface FastEthernet1/0 Neighbor priority is 1, State is FULL, 6 state changes DR is 140.100.17.129 BDR is 140.100.17.130 Options 2

Dead timer due in 00:00:35 Neighbor 140.100.17.131, interface address 140.100.17.131 In the area 3 via interface FastEthernet1/0 Neighbor priority is 1, State is FULL, 6 state changes DR is 140.100.17.129 BDR is 140.100.17.130 Options 2

Dead timer due in 00:00:34

continues

Example 5-11 Using the show ip ospf neighbor detail Command (Continued)

Neighbor 140.100.23.1 In the area 3 via Neighbor priority DR is 140.100.17.1 Options 2 Dead timer due in Neighbor 140.100.32.1 In the area 3 via Neighbor priority DR is 140.100.32.1 Options 2 Dead timer due in Neighbor 140.100.32.1 In the area 3 via Neighbor priority DR is 140.100.32.1 Options 2 Dead timer due in Neighbor 140.100.17.1 In the area 3 via Neighbor priority DR is 140.100.17.1 Options 2 Dead timer due in

, interface address 140.100.17.130 interface FastEthernet1/0 is 1, State is FULL, 6 state changes 29 BDR is 140.100.17.130

00:00:36

2, interface address 140.100.32.12 interface Fddi2/0

is 1, State is FULL, 6 state changes 1 BDR is 140.100.32.10

00:00:32

1, interface address 140.100.32.11 interface Fddi2/0

is 1, State is FULL, 6 state changes 1 BDR is 140.100.32.10

00:00:38

94, interface address 140.100.17.194 interface FastEthernet3/0 is 1, State is FULL, 9 state changes 94 BDR is 140.100.17.193

00:00:38

Table 5-11 explains the meanings of the important fields from Examples 5-9 through 5-11.

Table 5-11 Explanation of the show ip ospf neighbor Command

Table 5-11 explains the meanings of the important fields from Examples 5-9 through 5-11.

Table 5-11 Explanation of the show ip ospf neighbor Command

Field

Explanation

ID

This is the router ID.

Pri

This is the priority sent out with the Hello protocol to elect

the designated router and the backup designated router.

State

This shows the state, not of the link but whether the interface

was elected.

DR—Designated router.

BDR—Backup designated router.

DROTHER—The router was not chosen as the DR or the

BDR. If the priority on the interface had been set to zero, the

state would always be DROTHER because the router could

not be elected as a DR or a BDR.

Dead Time

The dead time is how long the router will wait without

hearing the periodic hello from its neighbor before it is

declared dead. This timer should be consistent on the

network; otherwise, there will be problems.

Table 5-11 Explanation of the show ip ospf neighbor Command (Continued)

Field

Explanation

Address

This is the interface address of the neighbor. Note that the

router ID is not the same as the interface address. If the

loopback address or the highest IP address on the router has

been used, the address probably will differ.

Interface

This is the outgoing interface of the router, upon which the

neighbor routers were heard.

Options

The option available is one of design. It identifies whether

the area the neighbors inhabit is a stub area. The next section

discusses this in detail.

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