RE: OSPF Inra Area route filtering

From: Mohmmad, Imran (Imran.Mohmmad@amd.com)
Date: Thu Apr 10 2008 - 16:34:01 ART


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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