OSPF DROTHER issue

[mohamedayach]

Am trying to make OSPF works over 4 routers but one of them always end up not working (DROTHER) here is my topology is it a normal behavior or something ?

[julijime · Accepted solution]

Hello Mohamed,

You might want to try changing the type of network between routers to "Point-to-Point" in that way no DR election should happen.

Hope that helps!

Julio

[mohamedayach]

you are right I just checked and my last router is using a broadcast network instead of point-to-point!

but I did not change the type I just dragged and dropped it there hence I have 3 questions:

1. why is it using broadcast instead of point to point
2. how to configure it the right way 
3. how to prevent it from happening in the future (may be answered by the answer of Q1)

thx in a dvance!

[InayathUlla Sharieff]

Mohamedayach,

Here is the bit of explanation on the default network type of OSPF on the interfaces:-

In a physical frame relay serial interface, the default network type of OSPF is (Non Broadcast).
 
In a multipoint frame relay serial subinterface, the default netork type of OSPF is (Non Broadcast).
 
In a point to point frame-relay serial subinterface, the default network type of OSPF is (Point to point

Hence to answer your question:

• why is it using broadcast instead of point to point  ---> Bcz of default method.
• how to configure it the right way --> You need to go and change it under the interface.
• how to prevent it from happening in the future (may be answered by the answer of Q1) -- you cant change it on serial interfaces you need to use ethernet connectivity.

HTH

•  

[mohamedayach]

Thx for your answer,

but under my serial interface s0/0/0 I did this 

R1(config)#int s0/0/0

R1(config-if)#en

R1(config-if)#encapsulation ppp ?

then the interface went down and when I did the same thing for the neighbor router interface it did came up but the same issue persisted:

R1#sh ip ospf interface s0/0/0

Serial0/0/0 is up, line protocol is up

Internet address is 192.168.1.1/30, Area 0

Process ID 1, Router ID 192.168.1.1, Network Type BROADCAST, Cost: 64

Transmit Delay is 1 sec, State DR, Priority 255

Designated Router (ID) 192.168.1.1, Interface address 192.168.1.1

No backup designated router on this network

Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5

Hello due in 00:00:02

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 192.168.2.1

Suppress hello for 0 neighbor(s)

[InayathUlla Sharieff · Accepted solution]

I just tested this on my packet tracer:

R1---S0/1/0-----------S0/1/0--R2

config:

interface Serial0/1/0
 ip address 192.168.0.1 255.255.255.0
 encapsulation ppp
!

router ospf 10
 log-adjacency-changes
 network 192.168.0.1 0.0.0.0 area 0

Router#sh ip ospf int s0/1/0

Serial0/1/0 is up, line protocol is up

  Internet address is 192.168.0.1/24, Area 0

  Process ID 10, Router ID 192.168.0.1, Network Type POINT-TO-POINT, Cost: 64

  Transmit Delay is 1 sec, State POINT-TO-POINT, Priority 0

  No designated router on this network

  No backup designated router on this network

Can you attach your pkt file so that I have look?

else you can also try this command:

Router(config)#int s0/1/0
Router(config-if)#ip ospf network point-to-point   >> this cmd will manually configure the port to be point to point.

HTH

regards

Inayath

**Please do not forget to rate all usefull posts.