RE: OSPF ID of 0.0.0.0

From: Jonathan Hays (nomad@gfoyle.org)
Date: Fri Dec 19 2003 - 18:14:28 GMT-3


you wrote:
Jonathan,

The question is probably asking you to put the routers in OSPF area 0.
[snip]
= = =

Brian

I think I have found another possible solution. Look at the output below
when I change the default network type with the command "ip ospf network
point-to-multipoint".

R2#show ip ospf neighbor detail | include DR
    DR is 0.0.0.0 BDR is 0.0.0.0
R2#

Since there were no constraints on the interface type in this problem, I
suspect they were hinting that you should change the network type. And
since point-to-multipoint doesn't use DR or BDR, the output of the "show
ip ospf neighbor detail" tags them both as 0.0.0.0, which meet the "DR
_and_ BDR" constraint of the problem statement.

What do you think?

See details below.

Jonathan

===============================
 OSPF network type nonbroadcast
===============================
R5#sh run int s1/0.100
Building configuration...

Current configuration : 242 bytes
!
interface Serial1/0.100 multipoint
 ip address 139.10.100.5 255.255.255.224
 frame-relay map ip 139.10.100.2 502 broadcast
 frame-relay map ip 139.10.100.4 504 broadcast
 frame-relay map ip 139.10.100.5 502
 no frame-relay inverse-arp
end

R5#sh ip ospf neighbor detail
 Neighbor 139.10.2.2, interface address 139.10.100.2
    In the area 0.0.0.0 via interface Serial1/0.100
    Neighbor priority is 0, State is FULL, 8 state changes
    DR is 139.10.100.5 BDR is 0.0.0.0
    Poll interval 120
    Options is 0x42
    Dead timer due in 00:01:45
    Neighbor is up for 00:10:14
    Index 1/1, retransmission queue length 0, number of retransmission 1
    First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0)
    Last retransmission scan length is 1, maximum is 1
    Last retransmission scan time is 0 msec, maximum is 0 msec
R5#
TermServer>2
[Resuming connection 2 to r6_2620 ... ]
[OK]
R2#
R2#sh run int s0/0
Building configuration...

Current configuration : 289 bytes
!
interface Serial0/0
 ip address 139.10.100.2 255.255.255.224
 encapsulation frame-relay
 ip ospf priority 0
 no fair-queue
 frame-relay map ip 139.10.100.2 205
 frame-relay map ip 139.10.100.4 205 broadcast
 frame-relay map ip 139.10.100.5 205 broadcast
 no frame-relay inverse-arp
end

R2#sh ip ospf nei detail
 Neighbor 139.10.5.5, interface address 139.10.100.5
    In the area 0.0.0.0 via interface Serial0/0
    Neighbor priority is 1, State is FULL, 6 state changes
    DR is 139.10.100.5 BDR is 0.0.0.0
    Poll interval 120
    Options is 0x42
    Dead timer due in 00:01:36
    Neighbor is up for 00:08:53
    Index 1/1, retransmission queue length 0, number of retransmission 2
    First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0)
    Last retransmission scan length is 1, maximum is 1
    Last retransmission scan time is 0 msec, maximum is 0 msec
R2#
=======================================
 OSPF network type point-to-multipoint
=======================================

R2#sh run int s0/0
Building configuration...

Current configuration : 326 bytes
!
interface Serial0/0
 ip address 139.10.100.2 255.255.255.224
 encapsulation frame-relay
 ip ospf network point-to-multipoint
 ip ospf priority 0
 no fair-queue
 frame-relay map ip 139.10.100.2 205
 frame-relay map ip 139.10.100.4 205 broadcast
 frame-relay map ip 139.10.100.5 205 broadcast
 no frame-relay inverse-arp
end

R2#sh ip ospf nei det
 Neighbor 139.10.5.5, interface address 139.10.100.5
    In the area 0.0.0.0 via interface Serial0/0
    Neighbor priority is 1, State is FULL, 6 state changes
    DR is 0.0.0.0 BDR is 0.0.0.0
    Options is 0x42
    Dead timer due in 00:01:53
    Neighbor is up for 00:00:15
    Index 1/1, retransmission queue length 0, number of retransmission 1
    First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0)
    Last retransmission scan length is 1, maximum is 1
    Last retransmission scan time is 0 msec, maximum is 0 msec
R2#



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