The actual interface type doesn't mater Raj :-). OSPF makes the
difference only between the network types, not physical media. In any
case, for your entertainment:
R1:
interface FastEthernet0/0
ip address 192.168.12.1 255.255.255.0
ip ospf network point-to-point
!
router ospf 1
network 192.168.0.0 0.0.255.255 area 0
!
R1#show ip ospf ne
Neighbor ID Pri State Dead Time Address Interface
192.168.0.2 0 FULL/ - 00:00:31 192.168.12.2
FastEthernet0/0
R1#show ip ospf data
OSPF Router with ID (192.168.0.1) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
192.168.0.1 192.168.0.1 82 0x80000002 0x00DE9B 3
192.168.0.2 192.168.0.2 83 0x80000006 0x004BA0 2
192.168.0.5 192.168.0.5 774 0x80000003 0x0091F4 2
Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
192.168.12.2 192.168.0.2 83 0x80000001 0x001A67
192.168.25.5 192.168.0.5 774 0x80000001 0x0086E3
R2:
interface GigabitEthernet0/0
ip address 192.168.12.2 255.255.255.0
ip ospf network broadcast
!
router ospf 1
network 192.168.0.0 0.0.255.255 area 0
!
R2#show ip ospf ne
Neighbor ID Pri State Dead Time Address Interface
192.168.0.1 1 FULL/BDR 00:00:32 192.168.12.1
GigabitEthernet0/0
R2#show ip ospf data
OSPF Router with ID (192.168.0.2) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
192.168.0.1 192.168.0.1 83 0x80000002 0x00DE9B 3
192.168.0.2 192.168.0.2 82 0x80000006 0x004BA0 2
192.168.0.5 192.168.0.5 773 0x80000003 0x0091F4 2
Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
192.168.12.2 192.168.0.2 82 0x80000001 0x001A67
192.168.25.5 192.168.0.5 773 0x80000001 0x0086E3
Here's when I switch them:
R1:
interface FastEthernet0/0
ip address 192.168.12.1 255.255.255.0
ip ospf network broadcast
!
R1#sh ip ospf ne
Neighbor ID Pri State Dead Time Address Interface
192.168.0.2 1 FULL/DR 00:00:38 192.168.12.2
FastEthernet0/0
R2:
interface GigabitEthernet0/0
ip address 192.168.12.2 255.255.255.0
ip ospf network point-to-point
!
R2#sh ip ospf ne
Neighbor ID Pri State Dead Time Address Interface
192.168.0.1 0 FULL/ - 00:00:35 192.168.12.1
GigabitEthernet0/0
See, no difference. I have some old ATM stuff lying around, want me to
try that too? ;-) As I said, this is such a common and nice problem,
we have it in a few of our troubleshooting labs (Volume 3).
--
Marko Milivojevic - CCIE #18427 (SP R&S)
Senior CCIE Instructor - IPexpert
On Tue, Jun 5, 2012 at 10:26 AM, HEMANTH RAJ <[email protected]> wrote:
> yeap gotcha , Try it on a ethernet interface, rather than a serial interface
> and see the fun.
>
> then try on one side as point to point and one side as Bcast and let me
> know the results
>
>
>
> On Tue, Jun 5, 2012 at 10:51 PM, Marko Milivojevic <[email protected]>
> wrote:
>>
>> There you go:
>>
>> R2---R5
>>
>> R2:
>> interface Serial0/2/0
>> ip address 192.168.25.2 255.255.255.0
>> ip ospf network point-to-point
>> !
>> router ospf 1
>> network 192.168.0.0 0.0.255.255 area 0
>> !
>>
>> R5:
>> interface Serial0/2/0
>> ip address 192.168.25.5 255.255.255.0
>> ip ospf network broadcast
>> !
>> router ospf 1
>> network 192.168.0.0 0.0.255.255 area 0
>> !
>>
>> R2:
>> R2#sh ip ospf nei
>>
>> Neighbor ID Pri State Dead Time Address
>> Interface
>> 192.168.0.5 0 FULL/ - 00:00:38 192.168.25.5
>> Serial0/2/0
>>
>> R2#sh ip ospf data
>>
>> OSPF Router with ID (192.168.0.2) (Process ID 1)
>>
>> Router Link States (Area 0)
>>
>> Link ID ADV Router Age Seq# Checksum Link count
>> 192.168.0.2 192.168.0.2 114 0x80000003 0x00F1E7 3
>> 192.168.0.5 192.168.0.5 115 0x80000003 0x0091F4 2
>>
>> Net Link States (Area 0)
>>
>> Link ID ADV Router Age Seq# Checksum
>> 192.168.25.5 192.168.0.5 115 0x80000001 0x0086E3
>>
>> R2#sh ip route ospf
>>
>>
>>
>> R5:
>>
>> R5#sh ip ospf nei
>>
>> Neighbor ID Pri State Dead Time Address
>> Interface
>> 192.168.0.2 1 FULL/BDR 00:00:36 192.168.25.2
>> Serial0/2/0
>>
>> R5#sh ip ospf data
>>
>> OSPF Router with ID (192.168.0.5) (Process ID 1)
>>
>> Router Link States (Area 0)
>>
>> Link ID ADV Router Age Seq# Checksum Link count
>> 192.168.0.2 192.168.0.2 115 0x80000003 0x00F1E7 3
>> 192.168.0.5 192.168.0.5 114 0x80000003 0x0091F4 2
>>
>> Net Link States (Area 0)
>>
>> Link ID ADV Router Age Seq# Checksum
>> 192.168.25.5 192.168.0.5 114 0x80000001 0x0086E3
>>
>> R5#sh ip route ospf
>>
>>
>> --
>> Marko Milivojevic - CCIE #18427 (SP R&S)
>> Senior CCIE Instructor - IPexpert
>>
>> On Tue, Jun 5, 2012 at 10:16 AM, Marko Milivojevic <[email protected]>
>> wrote:
>> > Try it... It's such a common problem we even have it in many of our
>> > workbooks.
>> >
>> > Link state updates are not multicast.
>> >
>> > --
>> > Marko Milivojevic - CCIE #18427 (SP R&S)
>> > Senior CCIE Instructor - IPexpert
>> >
>> > On Tue, Jun 5, 2012 at 10:10 AM, HEMANTH RAJ <[email protected]>
>> > wrote:
>> >> Hi Marko ,
>> >>
>> >> hmm i don't see my databases synchronized if i have one side as BCAST
>> >> and
>> >> other side as point to point.
>> >> how will DR accept on 224.0.0.5 if he thinks others are DRother
>> >> how will the DB are synced ?
>> >> could u explain me a bit more ?
>> >>
>> >>
>> >> On Tue, Jun 5, 2012 at 9:47 PM, Marko Milivojevic <[email protected]>
>> >> wrote:
>> >>>
>> >>> On Tue, Jun 5, 2012 at 9:10 AM, Venkee <[email protected]> wrote:
>> >>> > In this case, from one end (BCAST), would see the type-2 lsa in
>> >>> > database
>> >>> > but
>> >>> > not on router where we have p-t-p, he might have said this
>> >>>
>> >>> That is correct. However, if you look at the adjacency between the two
>> >>> routers, it would appear as perfectly valid and the databases will be
>> >>> in sync.
>> >>>
>> >>> Another difference you will see in the database is the type of link in
>> >>> Type-1 LSA that will be Point-to-point/Stub on the p2p side and
>> >>> Transit on the broadcast side. This discrepancy is the one routers
>> >>> will use to identify the problem and cause them not to "trust" each
>> >>> other.
>> >>>
>> >>> --
>> >>> Marko Milivojevic - CCIE #18427 (SP R&S)
>> >>> Senior CCIE Instructor - IPexpert
>> >>
>> >>
>> >>
>> >>
>> >> --
>> >> Problems arise because we talk,problems are not solved because we don't
>> >> talk
>> >> So good or bad talk to your affectionate one's freely.
>> >>
>> >> Yours Friendly,
>> >> H P HEMANTH RAJ
>> >> CCIE#28593 (R&S)
>> >>
>> >>
>
>
>
>
> --
> Problems arise because we talk,problems are not solved because we don't talk
> So good or bad talk to your affectionate one's freely.
>
> Yours Friendly,
> H P HEMANTH RAJ
> CCIE#28593 (R&S)
>
>
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