From: shiran guez (shiranp3@gmail.com)
Date: Thu Nov 08 2007 - 06:36:03 ART
to stop sending LSA will destroy the whole concept so you cant, if you are
talking on other the area 0 then you can filter LSA (Summarize) on the ABR
but yet again in the area it self you cant filter LSA between routers.
you can only filter what you are putting into the routing table.
I strongly suggest you will read RFC 2328 a very well written Doc cover all
you need to know about ospf http://www.faqs.org/rfcs/rfc2328.html
*"Link state databases must remain synchronized over all
adjacencies associated with the above eligible interfaces. This
is accomplished by executing the following steps on each
eligible interface. It should be noted that this procedure may
decide not to flood an LSA out a particular interface, if there
is a high probability that the attached neighbors have already
received the LSA. However, in these cases the flooding
procedure must be absolutely sure that the neighbors eventually
do receive the LSA, so the LSA is still added to each
adjacency's Link state retransmission list."
*
On Nov 8, 2007 11:19 AM, Gupta, Gopal (NWCC) <gopal.gupta@hp.com> wrote:
> 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 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 [110/65] via 155.2.13.1, 00:10:27, Serial1/0
> > [110/65] via 155.2.0.1, 00:10:27, Serial1/1
> >
> >
> > Config of R5
> >
> > interface Serial1/0
> > ip address 155.2.0.5 255.255.255.0
> > encapsulation frame-relay
> > ip split-horizon
> > ip ospf priority 2
> > frame-relay map ip 155.2.0.1 501
> > frame-relay map ip 155.2.0.3 503
> > frame-relay map ip 155.2.0.4 504
> > end
> >
> > Config of R3
> >
> > interface Serial1/1
> > ip address 155.2.0.3 255.255.255.0
> > encapsulation frame-relay
> > ip ospf priority 0
> > serial restart-delay 0
> > no dce-terminal-timing-enable
> > frame-relay map ip 155.2.0.5 305
> > end
> >
> > Config of R1
> >
> > interface Serial1/0
> > ip address 155.2.0.1 255.255.255.0
> > encapsulation frame-relay
> > ip ospf priority 0
> > serial restart-delay 0
> > no dce-terminal-timing-enable
> > frame-relay map ip 155.2.0.5 105
> > 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
>
-- Shiran Guez MCSE CCNP NCE1 http://cciep3.blogspot.com http://www.linkedin.com/in/cciep3
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