OSPF Network Point – to – Point

Lessons Learned:

# ip ospf network point-to-point

Default on point-to-point medias

--HDLC / PPP

Sends hellos as multicast

--224.0.0.5

No DR/ BDR Election

Supports only two neighbors on the link

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A point to point network will no longer generate an LSA type 2 because there is no DR or BDR on the segments.

You can also use point to point on other media (Ethernet) as long as there’s only two neighbors on the segment.

Network Types and Elections

DR / BDR Election	No Election
Broadcast and	P2P
Non-Broadcast	P2-Mulitpoint
	P2-p- non broadcast

Output from # sh ip ospf interface ser0/0

R6#sh ip ospf interface serial 0/0

Serial0/0 is up, line protocol is up

  Internet Address 10.1.56.6/24, Area 10.1.0.0

  Process ID 1234, Router ID 10.1.67.6, Network Type POINT_TO_POINT, Cost: 64 – Shows process, Network type

  Transmit Delay is 1 sec, State POINT_TO_POINT

  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 –Note: No need for the wait time on this link, we’re not running the DR and BDR elections.

    oob-resync timeout 40

    Hello due in 00:00:07

  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 10.54.4.5

  Suppress hello for 0 neighbor(s)

What is not supported for ADJ to occur via network types:

DR / BDR Election	No Election	NOT Supported
Broadcast and	P2P	P2P to Broadcast
Non-Broadcast	P2-Mulitpoint	P2MP to Broadcast
	P2-p- non broadcast	P2MP to Non-Broadcast

The routers will form a neighbor relationship if the network types are mismatched but will never form and ADJ.