From: Paul Cosgrove (paul.cosgrove@heanet.ie)
Date: Fri Apr 11 2008 - 19:02:02 ART
Sorry, the correct name for the book I mentioned is "Opimal Routing Design".
Paul Cosgrove wrote:
> Thanks Inran,
>
> You have tested and found that Type-3 default routes are denied by the
> database-filter, so as you said the original problem cannot be easily
> solved without default static routes (or another protocol) on the
> spokes. This would apply to both stub and totally stub areas as they
> cannot use any other type of default route. Since these routes are
> originated by the hub router, your tests suggest that the statement in
> Optimising Routing Protocols about database-filter only filtering
> received LSAs does not always apply.
> Ignoring Type-3 default routes (which your tests show do not work with
> this command), there are two other ways that default routes could be
> injected into OSPF hub and spoke: default routers could also be
> injected as Type-5 routes into a normal area, or Type-7 routes into a
> NSSA area. The book does not mention the area type and so I was
> wondering if the behaviour it describes occurs in either of those. If
> not then the statement in the book must be incorrect.
>
> Paul.
>
> Mohmmad, Imran wrote:
>> Hi Paul,
>>
>> If I have the "default-information originate always" on ABR, still there
>> will be no LSA advertisement including the default from ABR
>>
>> router ospf 10
>> log-adjacency-changes
>> area 45 stub no-summary
>> network 10.10.10.3 0.0.0.0 area 45
>> network 40.40.40.3 0.0.0.0 area 45
>> network 192.168.30.3 0.0.0.0 area 0
>> default-information originate always
>> !
>> A#sh run int se1/1
>> Building configuration...
>>
>> Current configuration : 198 bytes
>> !
>> interface Serial1/1
>> description ****Connected to B******
>> ip address 40.40.40.3 255.255.255.0
>> ip pim sparse-mode
>> encapsulation ppp
>> ip ospf database-filter all out
>> serial restart-delay 0
>>
>> B#sh ip os database
>>
>> OSPF Router with ID (2.2.2.2) (Process ID 10)
>>
>> Router Link States (Area 45)
>>
>> Link ID ADV Router Age Seq# Checksum Link
>> count
>> 2.2.2.2 2.2.2.2 40 0x80000001 0x007291 2
>> B#
>> B#
>> B#sh ip route ospf
>> B#sh ip route ospf
>>
>> Imran
>>
>> -----Original Message-----
>> From: Paul Cosgrove [mailto:paul.cosgrove@heanet.ie] Sent: Friday,
>> April 11, 2008 2:44 AM
>> To: Mohmmad, Imran
>> Cc: nagendra kumar; atif raees; ccielab@groupstudy.com
>> Subject: Re: OSPF Inra Area route filtering
>>
>> Hi Imran,
>>
>> Interesting. "Optimal routing design" discusses the two database filter
>>
>> commands with hub and spoke on pages 177/178. The section ends with:-
>>
>> "You can also originate a default route at the ABR using
>> default-information originate instead of static routes at the
>> remote-routers. The command ip ospf database-filter all out only
>> filteres learned LSAs, not locally originated ones, so a locally
>> generated default would still be sent to the remote routers"
>>
>> The preceding example in the book is a partial config which doesn't
>> specify an area type. I wonder if the different behaviour is related to
>>
>> the LSA type of the default, which with the totally stub will have to be
>>
>> Type 3?
>>
>> Paul.
>>
>> Mohmmad, Imran wrote:
>>
>>> It will block the advertisement of all LSA from interface including
>>>
>> the
>>
>>> default.
>>>
>>> DS1/0--------S1/1RP
>>> |
>>> |
>>> S1/0
>>> A
>>> |
>>> |
>>> /\
>>> / \
>>> / \
>>> S1/0 S1/0
>>> B C
>>>
>>> Router D, RP and router A S1/0 is in area 0 and the router A se1/1 and
>>> s1/2 in area 45 with two different point to point links.
>>>
>>> Once we configured the area 45 as totally-stub the OIA SLA that we can
>>> see on B and C is the default route and Router SLA for C link to
>>>
>> router
>>
>>> A
>>>
>>> A#sh run | sec router ospf
>>> router ospf 10
>>> log-adjacency-changes
>>> area 45 stub no-summary
>>> network 10.10.10.3 0.0.0.0 area 45 <Link to router C>
>>> network 40.40.40.3 0.0.0.0 area 45<Link to router B>
>>> network 192.168.30.3 0.0.0.0 area 0
>>>
>>> B#sh ip os database
>>>
>>> OSPF Router with ID (2.2.2.2) (Process ID 10)
>>>
>>> Router Link States (Area 45)
>>>
>>> Link ID ADV Router Age Seq# Checksum Link
>>> count
>>> 2.2.2.2 2.2.2.2 569 0x80000001 0x007291 2
>>> 3.3.3.3 3.3.3.3 663 0x80000004 0x00E2C9 2
>>> 150.1.3.3 150.1.3.3 588 0x8000000B 0x00DD9C 4
>>>
>>> Summary Net Link States (Area 45)
>>>
>>> Link ID ADV Router Age Seq# Checksum
>>> 0.0.0.0 150.1.3.3 677 0x80000001 0x003769
>>>
>>> B#sh ip route ospf
>>> 10.0.0.0/24 is subnetted, 1 subnets
>>> O 10.10.10.0 [110/128] via 40.40.40.3, 00:02:59, Serial1/0
>>> O*IA 0.0.0.0/0 [110/65] via 40.40.40.3, 00:02:59, Serial1/0
>>>
>>> A#sh run int se1/1
>>> Building configuration...
>>>
>>> Current configuration : 198 bytes
>>> !
>>> interface Serial1/1
>>> description ****Connected to B******
>>> ip address 40.40.40.3 255.255.255.0
>>> ip pim sparse-mode
>>> encapsulation ppp
>>> ip ospf database-filter all out
>>> serial restart-delay 0
>>>
>>> Once we filter-lsa advertisement on A, the B router is no longer have
>>> any OSPF LSA including the default Summary.
>>>
>>> B#sh ip os database
>>>
>>> OSPF Router with ID (2.2.2.2) (Process ID 10)
>>>
>>> Router Link States (Area 45)
>>>
>>> Link ID ADV Router Age Seq# Checksum Link
>>> count
>>> 2.2.2.2 2.2.2.2 3 0x80000001 0x007291 2
>>> B#
>>> B#
>>> B#sh ip os database
>>>
>>> OSPF Router with ID (2.2.2.2) (Process ID 10)
>>>
>>> Router Link States (Area 45)
>>>
>>> Link ID ADV Router Age Seq# Checksum Link
>>> count
>>> 2.2.2.2 2.2.2.2 6 0x80000001 0x007291 2
>>> B#sh ip route ospf
>>>
>>>
>>> Imran
>>>
>>>
>>>
>>> -----Original Message-----
>>> From: Paul Cosgrove [mailto:paul.cosgrove@heanet.ie] Sent: Thursday,
>>> April 10, 2008 3:14 AM
>>> To: nagendra kumar
>>> Cc: Mohmmad, Imran; atif raees; ccielab@groupstudy.com
>>> Subject: Re: OSPF Inra Area route filtering
>>>
>>> The command filters learned LSAs from being relayed on, so you
>>> should still be able to send a default from the hub.
>>>
>>> Paul.
>>>
>>> nagendra kumar wrote:
>>>
>>>> Hi,
>>>> I guess this command will filter all LSAs and so itz our
>>>>
>>> responsibility to configure a default route in all spoke routers.
>>>
>>>> Regards,
>>>> Nagendra
>>>>
>>>> Paul Cosgrove <paul.cosgrove@heanet.ie> wrote: neighbor x.x.x.x
>>>>
>>> database-filter all out
>>>
>>>> Paul.
>>>>
>>>> Mohmmad, Imran wrote:
>>>>
>>>>> Hi there,
>>>>>
>>>>> What you want to filter, route entering into the routing table from
>>>>>
>>> OSPF
>>>
>>>>> LSDB or the inter-area LSA itself?
>>>>>
>>>>> If you want to filter the route entering from OSPF LSDB to routing
>>>>>
>>> table
>>>
>>>>> you can use the distribute-list in on OSPF process,
>>>>>
>>>>> If you want to filter the Intra-Area LSA itself, then with in an
>>>>>
>> area
>>
>>> it
>>>
>>>>> is not possible.
>>>>>
>>>>> Imran
>>>>>
>>>>> -----Original Message-----
>>>>> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
>>>>>
>>> Of
>>>
>>>>> atif raees
>>>>> Sent: Wednesday, April 09, 2008 1:15 AM
>>>>> To: ccielab@groupstudy.com
>>>>> Subject: OSPF Inra Area route filtering
>>>>>
>>>>> Dear all
>>>>>
>>>>> i am experimenting a hub & spoke topology using FR.
>>>>>
>>>>> Each spoke has it on LAN
>>>>>
>>>>> Hub has area 0 & area 1 as totally stub are all FR spoke are in Area
>>>>>
>>> 1
>>>
>>>>> what i want to achieve is to filter (intra area ospf routes sent by
>>>>>
>>> each
>>>
>>>>> spoke) at hub site so that spoke can has just default route in it
>>>>> routing
>>>>> table which they already have as i have configured area 1 as totally
>>>>> stub.
>>>>>
>>>>> is it possible.
>>>>>
>>>>> Atif Raees
>>>>>
>>>>>
>>>>>
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