From: Ahsan Mohiuddin (ahsan.mohiuddin@yahoo.com)
Date: Thu Nov 08 2007 - 07:58:22 ART
thanks everyone, for your inputs and insight..
shiran guez <shiranp3@gmail.com> wrote: Alexander
it is not only that you shouldnt filter LSA, you cant what will happen if you filter protocol id 89 your neighbor relation will be terminated.
also if you had a way to filter you would miss the concept states in the RFC that any LSA sent must recive ack from all the neighbor. so you simply can't do it in OSPF, this is why I recommanded to read the RFC as it states plan and simple the proccess of DB building and what each Router should do when it is participating in the OSPF area.
Also according to the RFC the OSPF have a DB table not a TOPOLOGY table.
the diffrance is that a topology show you the cost to each route, and a DB is showing you the advertisments and there originator ID. from the DB you cant realy know what route is prefered and from a TOPOLOGY table you can (like EIGRP have)
On Nov 8, 2007 12:10 PM, Alexander Belov <abelov@technoserv.ru> wrote:
Hello Gops!
What Shiran is said is - the DB is the TOPOLOGY table that is unique, the
same, on all Routers within the Area.
LSAs are sent between routers and they used to build Topology table from
that router may take the path to some destination - so You have to filter
specific routers on the target router from letting them be put from topology
table into routing table.
LSAs should not be filtered - it will brake the ospf :)
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Gupta, Gopal (NWCC)
Sent: Thursday, November 08, 2007 12:19 PM
To: shiran guez
Cc: Ahsan Mohiuddin; ccielab@groupstudy.com
Subject: RE: ip split horizon letting ospf routes slip through
Hi Shiran,
Thanks for the reply, could you please throw some light , is there one
and only one way to filter routes in the same area i.e. configuring
locally on every router to filter routes from entering into the routing
table ?? or can we configure the advertising router to stop sending the
updates or LSAs to its neighbor ??
Regards,
Gops
From: shiran guez [mailto:shiranp3@gmail.com]
Sent: Thursday, November 08, 2007 14:42
To: Gupta, Gopal (NWCC)
Cc: Ahsan Mohiuddin; ccielab@groupstudy.com
Subject: Re: ip split horizon letting ospf routes slip through
Gops
Nothing is blocking LSA in OSPF area accept link down as it is Link
State Protocol and his whole concept is one DB same to all neighbors.
Distance is locally significant and not advertised! so what you will do
is only block your self from using the route but not block the LSA from
going to your neighbors.
In an AREA all NEIGHBORS SHARE THE SAME DB.
On Nov 8, 2007 10:50 AM, Gupta, Gopal (NWCC) <gopal.gupta@hp.com> wrote:
Hi Ahsan,
As far as I know split horizon cannot block OSPF LSAs.
What you can do is filter routes on R3 using Distance 255 for
the route
coming from R5.
HTH
Gops
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On
Behalf Of
Ahsan Mohiuddin
Sent: Thursday, November 08, 2007 14:01
To: ccielab@groupstudy.com
Subject: ip split horizon letting ospf routes slip through
Importance: Low
hello group,
i have routers R1, R3 (FR spokes) connected to Hub R5. R1 is
advertising
route 155.2.146.0 <http://155.2.146.0/> to R5, but I do not
want R5 to send this update to R3.
So, I have configured "ip split-horion" under R5's physical
interface
(subinterfaces not used). But it seems R3 is still learning the
route
from R1:
O 155.2.146.0 <http://155.2.146.0/> [110/65] via
155.2.13.1 <http://155.2.13.1/> , 00:10:27, Serial1/0
[110/65] via 155.2.0.1 < http://155.2.0.1/> ,
00:10:27, Serial1/1
Config of R5
interface Serial1/0
ip address 155.2.0.5 < http://155.2.0.5/> 255.255.255.0
<http://255.255.255.0/>
encapsulation frame-relay
ip split-horizon
ip ospf priority 2
frame-relay map ip 155.2.0.1 < http://155.2.0.1/> 501
frame-relay map ip 155.2.0.3 <http://155.2.0.3/> 503
frame-relay map ip 155.2.0.4 <http://155.2.0.4/> 504
end
Config of R3
interface Serial1/1
ip address 155.2.0.3 < http://155.2.0.3/> 255.255.255.0
<http://255.255.255.0/>
encapsulation frame-relay
ip ospf priority 0
serial restart-delay 0
no dce-terminal-timing-enable
frame-relay map ip 155.2.0.5 <http://155.2.0.5/> 305
end
Config of R1
interface Serial1/0
ip address 155.2.0.1 < http://155.2.0.1/> 255.255.255.0
<http://255.255.255.0/>
encapsulation frame-relay
ip ospf priority 0
serial restart-delay 0
no dce-terminal-timing-enable
frame-relay map ip 155.2.0.5 <http://155.2.0.5/> 105
end
Any idea what i am doing wrong here?
Thanks in adv
-Ahsan
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This archive was generated by hypermail 2.1.4 : Sat Dec 01 2007 - 06:37:28 ART