From: Fahad Khan (fahad.khan@gmail.com)
Date: Tue Aug 05 2008 - 15:41:26 ART
Dear Abbas bhai,
Thank you, I had gone through this one. Plz tell me the difference between
the usage of "ip ospf priority" command under interface mode and "neighbour
<ip> priority" command under router mode
On 8/5/08, Mohammed Abbas <sweetabuli@gmail.com> wrote:
>
> 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
>>
>> _______________________________________________________________________
>> Subscription information may be found at:
>> http://www.groupstudy.com/list/CCIELab.html
>>
>>
>>
>>
>>
>>
>>
>>
>
-- *FAHAD KHANBE Computer Systems NED,
CCNA,CCDA,CCNP,FOUNDFE,CLSE,QOS,JNCIA,JNCIS,MCP,CCIE (Written)
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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