From: Mohammed Abbas (sweetabuli@gmail.com)
Date: Tue Aug 05 2008 - 10:45:07 ART
Hi Fahad,
Please find the reply for your first question (From Cisco Website)
*neighbor (OSPF) *
To configure Open Shortest Path First (OSPF) routers interconnecting to
nonbroadcast networks, use the *neighbor *command in router address family
topology or router configuration mode. To remove a configuration, use the *
no* form of this command.
*neighbor* *ip-address* [*priority** number*] [*poll-interval* *seconds*] [*
cost** number*] [*database-filter all*]
*no neighbor* *ip-address* [*priority** number*] [*poll-interval* *seconds*]
[*cost** number*] [*database-filter all*]
*Syntax Description*
*ip-address*
Interface IP address of the neighbor.
*priority** number*
(Optional) A number that indicates the router priority value of the
nonbroadcast neighbor associated with the IP address specified.* *The
default is 0. This keyword does not apply to point-to-multipoint interfaces.
*poll-interval **seconds*
(Optional) A number value that represents the poll interval time (in
seconds). RFC 1247 recommends that this value be much larger than the hello
interval. The default is 120 seconds (2 minutes). This keyword does not
apply to point-to-multipoint interfaces. The range is from 0 to 4294967295
seconds.
*cost** number*
(Optional) Assigns a cost to the neighbor, in the form of an integer from 1
to 65535. Neighbors with no specific cost configured will assume the cost of
the interface, based on the *ip ospf cost *command. For point-to-multipoint
interfaces, the cost keyword and the *number* argument are the only options
that are applicable. This keyword does not apply to nonbroadcast multiaccess
(NBMA) networks.
*database-filter all*
(Optional) Filters outgoing link-state advertisements (LSAs) to an OSPF
neighbor.
*Command Default *
This command is disabled by default. No configuration is specified.
*Command Modes *
Router address family topology configuration (config-router-af-topology)
Router configuration (config-router)
*Command History*
*Release *
*Modification *
10.0
This command was introduced.
11.3AA
The *cost* keyword was added.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2(33)SRB
This command was made available in router address family topology
configuration mode.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in
a specific 12.2SX release of this train depends on your feature set,
platform, and platform hardware.
*Usage Guidelines *
X.25 and Frame Relay provide an optional broadcast capability that can be
configured in the map to allow OSPF to run as a broadcast network. At the
OSPF level you can configure the router as a broadcast network. Refer to the
* x25 map* and *frame-relay map* commands in the "X.25 Commands" and "Frame
Relay Commands" chapters, respectively, in the *Cisco IOS* *Wide-Area
Networking Command Reference *for more detail.
One neighbor entry must be included in the Cisco IOS software configuration
for each known nonbroadcast network neighbor. The neighbor address must be
on the primary address of the interface.
If a neighboring router has become inactive (hello packets have not been
received for the Router Dead Interval period), it may still be necessary to
send hello packets to the dead neighbor. These hello packets will be sent at
a reduced rate called *Poll Interval*.
When the router first starts up, it sends only hello packets to those
routers with nonzero priority, that is, routers that are eligible to become
designated routers (DRs) and backup designated routers (BDRs). After the DR
and BDR are selected, DR and BDR will then start sending hello packets to
all neighbors in order to form adjacencies.
------------------------------
*Note *You cannot use the *neighbor (OSPF)* command to specify an Open
Shortest Path First (OSPF) neighbor on non-broadcast networks within an OSPF
Virtual Private Network (VPN) routing instance.
------------------------------
Prior to Cisco IOS Release 12.0, the *neighbor* command applied to NBMA
networks only. With Release 12.0, the *neighbor* command applies to NBMA
networks and point-to-multipoint networks. On NBMA networks, the
*cost*keyword is not accepted.
Release 12.2(33)SRB
If you plan to configure the Multi-Topology Routing (MTR) feature, you need
to enter the *neighbor *command in router address family topology
configuration mode in order for this OSPF router configuration command to
become topology-aware.
*Examples *
The following example declares a router at address 192.168.3.4 on a
nonbroadcast network, with a priority of 1 and a poll interval of 180
seconds:
router ospf
neighbor 192.168.3.4 priority 1 poll-interval 180
The following example illustrates a point-to-multipoint network with
nonbroadcast:
interface Serial0
ip address 10.0.1.1 255.255.255.0
ip ospf network point-to-multipoint non-broadcast
encapsulation frame-relay
no keepalive
frame-relay local-dlci 200
frame-relay map ip 10.0.1.3 202
frame-relay map ip 10.0.1.4 203
frame-relay map ip 10.0.1.5 204
no shut
!
router ospf 1
network 10.0.1.0 0.0.0.255 area 0
neighbor 10.0.1.3 cost 5
neighbor 10.0.1.4 cost 10
neighbor 10.0.1.5 cost 15
*Related Commands*
*Command *
*Description *
*ip ospf priority*
Sets the router priority, which helps determine the designated router for
this network.
Best regards!
Mohammed Abbas
On 8/5/08, Fahad Khan <fahad.khan@gmail.com> wrote:
>
> sorry , i forgot to add "not" in my last line."
>
> ---------- Forwarded message ----------
> From: Fahad Khan <fahad.khan@gmail.com>
> Date: Aug 5, 2008 2:54 PM
> Subject: OSPF queries!!!
> To: GS CCIE-Lab <ccielab@groupstudy.com>
>
> Dear experts,
>
> Kindly resolve my queries reagrding OSPF given below
>
> 1- Why would I use the command "neighbour <ip> priority"?
>
> 2- I tried to send the summary routes from R1 over Virtual-link and GRE
> both
> , but couldn't get summary route on R4
>
> Scenario : R1----area0-----R2------area1-----R3------area2-------R4
>
> I may have done any mistake, but plz let me know is it possible?
>
> 3- I have heared from some one that "area <id> range <address> <net mask>
> not-advertise" filters type 1 LSA. Can any one plz elaborate it (i think
> this relates with LSA type 3) and also tell me why would i use it, If i can
> simple not advertise networks in my routing process, then definitely routes
> would not be advertised
>
> Thanks and regards,
>
> --
> FAHAD KHAN
>
> BE Computer Systems NED,
>
> CCNA,CCDA,CCNP,FOUNDFE,CLSE,QOS,JNCIA,JNCIS,MCP
>
> Systems Support Engineer, Premier Systems (Pvt) limited,
>
> Karachi, Pakistan
>
> 92-321-2370510.
>
>
> Blogs and organic groups at http://www.ccie.net
>
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