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OSPF point to multi-point network has Hellos sent as Unicast?

Ravi Pande
Level 1
Level 1

I was reading about Hellos sent to 224.0.0.5 in Broadcast(Multi-access) and Point to point network type however there are unicast Hellos for NBMA,Point to multi-point and Virtual link.

I implemented point to multi-point with 2 routers R1<--------->R2 connected using serial link and configured the serial interfaces with "ip ospf network point-to-multipoint" command. I am still seeing the Hellos sent to 224.0.0.5

However when I do 'sh ip ospf int s2/0'

 

Serial2/0 is up, line protocol is up
Internet Address 192.168.1.2/24, Area 1
Process ID 1, Router ID 192.168.1.2, Network Type POINT_TO_MULTIPOINT, Cost: 64
Transmit Delay is 1 sec, State POINT_TO_MULTIPOINT
Timer intervals configured, Hello 30, Dead 120, Wait 120, Retransmit 5
oob-resync timeout 120
Hello due in 00:00:18
Supports Link-local Signaling (LLS)
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 192.168.1.1
Suppress hello for 0 neighbor(s)

 

I used debug ip ospf hello command on the same router and observe that Hellos are sent as Multicast to 224.0.0.5

 

R7#debug ip ospf hello
OSPF hello events debugging is on
R7#
*Mar 1 00:18:52.459: OSPF: Send hello to 224.0.0.5 area 1 on Serial2/0 from 192.168.1.2
R7#
*Mar 1 00:19:08.523: OSPF: Rcv hello from 192.168.1.1 area 1 from Serial2/0 192.168.1.1
*Mar 1 00:19:08.523: OSPF: End of hello processing
R7#
*Mar 1 00:19:22.459: OSPF: Send hello to 224.0.0.5 area 1 on Serial2/0 from 192.168.1.2\

 

Can anybody explain why I am seeing a multicast Hello in point to multi-point network?

 

1 Accepted Solution

Accepted Solutions

Deepak Kumar
VIP Alumni
VIP Alumni
Hi,
Please use the command "ip ospf network point-to-multipoint non-broadcast"
There are two type of Point-to-Multipoint (broadcast) Network and Point-to-Multipoint non-broadcast Network.

Reference Link: https://ccieblog.co.uk/ospf/ospf-hello-protocol

Regards,
Deepak Kumar
Regards,
Deepak Kumar,
Don't forget to vote and accept the solution if this comment will help you!

View solution in original post

1 Reply 1

Deepak Kumar
VIP Alumni
VIP Alumni
Hi,
Please use the command "ip ospf network point-to-multipoint non-broadcast"
There are two type of Point-to-Multipoint (broadcast) Network and Point-to-Multipoint non-broadcast Network.

Reference Link: https://ccieblog.co.uk/ospf/ospf-hello-protocol

Regards,
Deepak Kumar
Regards,
Deepak Kumar,
Don't forget to vote and accept the solution if this comment will help you!
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