From: shiran guez (shiranp3@gmail.com)
Date: Thu Nov 08 2007 - 07:20:47 ART
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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> --
> Shiran Guez
> MCSE CCNP NCE1
> http://cciep3.blogspot.com
> http://www.linkedin.com/in/cciep3
>
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>
-- Shiran Guez MCSE CCNP NCE1 http://cciep3.blogspot.com http://www.linkedin.com/in/cciep3
This archive was generated by hypermail 2.1.4 : Sat Dec 01 2007 - 06:37:28 ART