Awkward: OSPF on Non_Broadcast network works without adding

From: Joseph Saad (joseph.s.saad@gmail.com)
Date: Sat Jul 28 2007 - 12:14:04 ART


To start, I am using Dynamips till I get my faulty FR Switch replaced.

 

I read all the posts and documents and when it comes to OSPF over FR the
default IP OSPF network type is "NON_Broadcast".

 

Here's the case. I have built an FR network:

Hub & 2 spokes.

All supports broadcasts.

No use of inverse ARP.

All on Physical interfaces and using static frame map ip statements.

 

The instructions are that I should configure the interface as "ip ospf
network broadcast", but I didn't.

I didn't configure "Neighbor" also on any of the 3 routers.

 

To my surprise, the neighbors were discovered and after a minute adjacencies
went into FULL including the DR election.

 

Here's the relevant config. And I appreciate if somebody can tell me why
this behavior is occurring?

 

Note (R1) is the hub. R4 and R5 are spokes.

 

Rack1RX#sh ver | in Version

Cisco IOS Software, 3600 Software (C3640-JS-M), Version 12.4(12), RELEASE
SOFTWARE (fc1)

 

 

!!!!!!!!!!R1

 

Rack1R1#sh run int s1/0

!

interface Serial1/0

 ip address 10.0.0.1 255.0.0.0

 encapsulation frame-relay

 serial restart-delay 0

frame-relay map ip 10.0.0.4 104 broadcast

 frame-relay map ip 10.0.0.5 105 broadcast

 no frame-relay inverse-arp

end

 

Rack1R1#sh runn | b router ospf

router ospf 1

                log-adjacency-changes

                network 0.0.0.0 255.255.255.255 area 0

 

Rack1R1#sh ip ospf ne

 

Neighbor ID Pri State Dead Time Address Interface

10.0.0.4 0 FULL/DROTHER 00:01:30 10.0.0.4 Serial1/0

10.0.0.5 0 FULL/DROTHER 00:01:33 10.0.0.5 Serial1/0

 

Rack1R1#sh ip ospf int s1/0

Serial1/0 is up, line protocol is up

  Internet Address 10.0.0.1/8, Area 0

  Process ID 1, Router ID 10.0.0.1, Network Type NON_BROADCAST, Cost: 64

  Transmit Delay is 1 sec, State DR, Priority 1

  Designated Router (ID) 10.0.0.1, Interface address 10.0.0.1

  No backup designated router on this network

  Timer intervals configured, Hello 30, Dead 120, Wait 120, Retransmit 5

    oob-resync timeout 120

    Hello due in 00:00:29

 

 

 

!!!!!!!!!!!!!R4

Rack1R4#sh runn int s1/0

!

interface Serial1/0

 ip address 10.0.0.4 255.0.0.0

 encapsulation frame-relay

 ip ospf priority 0

 frame-relay map ip 10.0.0.1 401 broadcast

 frame-relay map ip 10.0.0.5 401

 no frame-relay inverse-arp

end

 

Rack1R4#sh runn | b router ospf 1

router ospf 1

 log-adjacency-changes

 network 0.0.0.0 255.255.255.255 area 0

!

 

Rack1R4#sh ip ospf int s1/0

Serial1/0 is up, line protocol is up

  Internet Address 10.0.0.4/8, Area 0

  Process ID 1, Router ID 10.0.0.4, Network Type NON_BROADCAST, Cost: 64

  Transmit Delay is 1 sec, State DROTHER, Priority 0

  Designated Router (ID) 10.0.0.1, Interface address 10.0.0.1

  No backup designated router on this network

  Timer intervals configured, Hello 30, Dead 120, Wait 120, Retransmit 5

  .

 .

 .

  Adjacent with neighbor 10.0.0.1 (Designated Router)

  Suppress hello for 0 neighbor(s)

 

Rack1R4#sh ip ospf neighbor

 

Neighbor ID Pri State Dead Time Address Interface

10.0.0.1 1 FULL/DR 00:01:33 10.0.0.1 Serial1/0

 

 

!!!!!!!!!!!!!!!R5

 

Rack1R5#sh runn int s1/0

!

interface Serial1/0

 ip address 10.0.0.5 255.0.0.0

 encapsulation frame-relay

 ip ospf priority 0

 frame-relay map ip 10.0.0.1 501 broadcast

 frame-relay map ip 10.0.0.4 501

 no frame-relay inverse-arp

end

 

Rack1R5#sh runn | b router ospf 1

router ospf 1

 log-adjacency-changes

 network 0.0.0.0 255.255.255.255 area 0

Serial1/0 is up, line protocol is up

  Internet Address 10.0.0.5/8, Area 0

  Process ID 1, Router ID 10.0.0.5, Network Type NON_BROADCAST, Cost: 64

  Transmit Delay is 1 sec, State DROTHER, Priority 0

  Designated Router (ID) 10.0.0.1, Interface address 10.0.0.1

  No backup designated router on this network

  Timer intervals configured, Hello 30, Dead 120, Wait 120, Retransmit 5



This archive was generated by hypermail 2.1.4 : Sat Aug 18 2007 - 08:17:42 ART