19-19 ip ospf retransmit-interval seconds

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19-19 ip ospf retransmit-interval seconds

Syntax Description:

  • seconds ” The range of values is 1 to 8192 seconds. The default value is 5 seconds.

Purpose: When a router advertises an LSA over an interface, the LSA is added to a retransmission list for the interface. The LSA will be retransmitted until it is acknowledged . The number of seconds between the advertisements is called the retransmit interval.

Initial Cisco IOS Software Release: 10.0

Configuration Example: Modifying the Retransmit Interval

Configure the network in Figure 19-15 so you can observe the default timer values over the serial link. You will then experiment by adjusting the values of the retransmit interval.

Figure 19-15. The Retransmit Interval Is the Time Between Resending Unacknowledged LSAs

graphics/19fig15.gif

 Router A  interface Loopback0   ip address 1.1.1.1 255.255.255.255   !   interface Serial0/1   bandwidth 64   ip address 10.1.1.1 255.255.255.252   clockrate 64000   !   router ospf 1   network 1.1.1.1 0.0.0.0 area 1   network 10.1.1.0 0.0.0.3 area 0  ______________________________________________________________________________ Router B  interface Loopback0   ip address 2.2.2.2 255.255.255.255   !   interface Serial0   ip address 10.1.1.2 255.255.255.252   bandwidth 64   !   router ospf 1   network 2.2.2.2 0.0.0.0 area 2   network 10.1.1.0 0.0.0.3 area 0  

Verify that Routers A and B have formed an OSPF neighbor relationship.

 rtrA#  show ip ospf neighbor  Neighbor ID     Pri   State           Dead Time   Address         Interface 2.2.2.2           1  FULL/  -  00:00:31    10.1.1.2        Serial0/1 

Examine the default retransmission interval by inspecting the OSPF interface properties on Routers A and B.

 rtrA#  show ip ospf int serial 0/1  Serial0/1 is up, line protocol is up   Internet Address 10.1.1.1/30, Area 0   Process ID 1, Router ID 1.1.1.1, Network Type POINT_TO_POINT, Cost: 1562   Transmit Delay is 1 sec, State POINT_TO_POINT,   Timer intervals configured, Hello 10, Dead 40, Wait 40,  Retransmit 5  Hello due in 00:00:07   Index 1/1, flood queue length 0   Next 0x0(0)/0x0(0)   Last flood scan length is 1, maximum is 1   Last flood scan time is 0 msec, maximum is 0 msec   Neighbor Count is 1, Adjacent neighbor count is 1     Adjacent with neighbor 2.2.2.2   Suppress hello for 0 neighbor(s) ____________________________________________________________________________ rtrB#  show ip ospf interface serial 0  Serial0 is up, line protocol is up   Internet Address 10.1.1.2/30, Area 0   Process ID 1, Router ID 2.2.2.2, Network Type POINT_TO_POINT, Cost: 1562   Transmit Delay is 1 sec, State POINT_TO_POINT,   Timer intervals configured, Hello 10, Dead 40, Wait 40,  Retransmit 5  Hello due in 00:00:05   Neighbor Count is 1, Adjacent neighbor count is 1     Adjacent with neighbor 1.1.1.1   Suppress hello for 0 neighbor(s) 

Change the retransmission interval on Router A to 10 seconds.

 Router A  interface Serial0/1   bandwidth 64   ip address 10.1.1.1 255.255.255.252    ip ospf retransmit-interval 10    clockrate 64000  

Unlike the Hello interval (discussed in Section 9-10) and the dead interval (discussed in Section 19-7), the retransmit interval does not have to be the same on every interface attached to a common network.

Verification

Verify that the new retransmit interval has been configured on Router A.

 rtrA#  show ip ospf interface serial 0/1  Serial0/1 is up, line protocol is up   Internet Address 10.1.1.1/30, Area 0   Process ID 1, Router ID 1.1.1.1, Network Type POINT_TO_POINT, Cost: 1562   Transmit Delay is 1 sec, State POINT_TO_POINT,   Timer intervals configured, Hello 10, Dead 40, Wait 40,  Retransmit 10  Hello due in 00:00:04   Index 1/1, flood queue length 0   Next 0x0(0)/0x0(0)   Last flood scan length is 1, maximum is 1   Last flood scan time is 0 msec, maximum is 0 msec   Neighbor Count is 1, Adjacent neighbor count is 1     Adjacent with neighbor 2.2.2.2   Suppress hello for 0 neighbor(s) 

Verify that Routers A and B have an OSPF neighbor relationship.

 rtrA#  show ip ospf neighbor  Neighbor ID     Pri   State           Dead Time   Address         Interface 2.2.2.2           1  FULL/  -  00:00:37    10.1.1.2        Serial0/1 
Troubleshooting
Step 1. Verify that there is a neighbor relationship between the OSPF routers by using the show ip ospf neighbor command.

Step 2. Verify that the desired retransmit interval has been configured by using the command show ip ospf interface.

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Cisco[r] OSPF Command and Configuration Handbook
Cisco OSPF Command and Configuration Handbook (paperback)
ISBN: 1587055406
EAN: 2147483647
Year: 2002
Pages: 236

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