From: david robin (robindavi@gmail.com)
Date: Thu Oct 12 2006 - 05:56:56 ART
Dear All,
yep I mean neighbor proiority without puting any interface ospf priority
commands.
the question was can we achieve the same result without puting ip ospf
priority 0 in spokes interfaces.
I try to do it but I fail every time a DR/BDR connection is established not
/Drother ( I m on the hub router)
I
On 10/11/06, Alexei Monastyrnyi <alexeim@orcsoftware.com> wrote:
>
> Your understanding is quite similar to mine :-)
>
> The question, however, was regarding "neighbor X priority Y" under OSPF
> process configuration...
>
> A.
>
> Michael Zuo wrote:
> > Here is my understanding (Correct me if I am wrong):
> >
> > This command influences which router will become DR and is especially
> > important in the "non-broadcast" hub and spoke setup. "ip priority 0"
> > takes that router out of the DR selection completely. This is the only
> > safe way to go since "ip priority X" command is not pre-emptive and any
> > other value than 0 will produce unpredictable results from DR selection
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> > Alexei Monastyrnyi
> > Sent: Sunday, October 08, 2006 7:27 AM
> > To: david robin
> > Cc: Noble, TN; Cisco certification
> > Subject: Re: neighbor priority commands
> >
> > Hi.
> >
> > Usual way is to set "ip ospf priority 0" on spokes' interfaces towards
> > hub router and "neighbor _spoke_IP_ " under ospf process of hub router
> > for each spoke. _spoke_IP_ is an IP address of spoke connected NBMA
> > interface, not an OSPF router ID of the neighbor. OSPF network type for
> > interfaces should be non-broadcast, if we mean to elect DR.
> >
> > With this you don't have to use "priority keyword for neighbor
> > statement.
> >
> > Because of limited experience I can not provide an example where such a
> > keyword would be useful. Though it would be interesting to know... :-)
> >
> >
> > HTH
> > A.
> >
> > david robin wrote:
> >
> >> But the problem is that I try to make the hub router as DR and the
> >>
> > other
> >
> >> routers as Drother, but it can't be accomplished, could you tell me
> >>
> > how can
> >
> >> we accomplish this, also the documentation CD say the default priority
> >>
> > is 0
> >
> >> not 1 which makes me confused more.
> >>
> >>
> >>
> >>
> >> On 10/7/06, Alexei Monastyrnyi <alexeim@orcsoftware.com> wrote:
> >>
> >>
> >>> Seems like it is a whole lot of confusion here.. even in CiscoPress
> >>>
> > :-)
> >
> >>> From Cisco(r) OSPF Command and Configuration Handbook (CCIE
> >>>
> > Professional
> >
> >>> Development)
> >>>
> >>>
> >>> 11-5. neighbor ip-address priority priority
> >>>
> >>> Syntax Description:
> >>>
> >>> *
> >>>
> >>> ip-address IP address of the OSPF neighbor. If a secondary
> >>> address is used on the interface, then the primary address must
> >>>
> > be
> >
> >>> used with this command because OSPF will only form an adjacency
> >>> using the primary address.
> >>>
> >>> *
> >>>
> >>> priority The OSPF priority of the neighbor with the given IP
> >>> address. The range of values is 0 to 255. _The router with the
> >>> lowest OSPF priority on a network will be elected the DR for the
> >>> network._ A priority of zero means that the router is not
> >>>
> > eligible
> >
> >>> to be elected the DR or Backup Designated Router (BDR). _The
> >>> default priority is 1_.
> >>>
> >>> Pay attention to _ ... _ statements :-) They seemingly messed up
> >>> priority in general and priority defaults for the particular command.
> >>>
> >>> From 12.3 DocCD
> >>>
> >>>
> >>>
> >>>
> > http://www.cisco.com/univercd/cc/td/doc/product/software/ios123/123cgcr/
> > iprrp
> >
> >> _r/ip2_n1g.htm#wp1036543
> >>
> >>
> >>> *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.
> >>>
> >>>
> >>> From what I can see on routers (IOS 12.3), for NBMA hub router with
> >>> this command applied towards spokes and spokes with default priority
> >>>
> > 1,
> >
> >>> you accomplish nothing.
> >>>
> >>> Just a quick example. For hub router with lo0 9.9.4.4/32 and "ip ospf
> >>> priority 3" on NNBMA interface, after "clear ip ospf proc" on all
> >>>
> > three
> >
> >>> boxes, I have, as expected.
> >>>
> >>> BB4#sh ip ospf nei
> >>>
> >>> Neighbor ID Pri State Dead Time Address Interface
> >>> 9.9.2.2 1 FULL/BDR 00:01:54 9.9.123.2 Serial0
> >>> 9.9.1.1 1 FULL/DROTHER 00:01:35 9.9.123.1 Serial0
> >>> BB4#sh run | beg router
> >>> router ospf 100
> >>> log-adjacency-changes
> >>> network 9.9.123.0 0.0.0.255 area 0
> >>> neighbor 9.9.123.2 priority 1
> >>> neighbor 9.9.123.1 priority 2
> >>>
> >>> After "clear ip ospf proc" on the hub router we have.
> >>> BB4#sh ip ospf nei
> >>>
> >>> Neighbor ID Pri State Dead Time Address Interface
> >>> 9.9.2.2 1 FULL/DR 00:01:53 9.9.123.2 Serial0
> >>> 9.9.1.1 1 FULL/BDR 00:01:59 9.9.123.1 Serial0
> >>>
> >>> Which is also expected. But I don't see any place where " neighbor
> >>>
> > ...
> >
> >>> priority.. " comes into play.
> >>>
> >>> It is probably useful for more complex mesh than hub and spoke.
> >>>
> >>> A.
> >>>
> >>>
> >>> Noble, TN wrote:
> >>>
> >>>
> >>>> The priority command does the same thing irrespective of the place
> >>>>
> > it is
> >
> >>>> applied. I mean, ip ospf priority 0 and neighbour 1.2.3.4 priority 0
> >>>> (optional and 0 is defaul) should do the same for us.
> >>>>
> >>>> Thank you,
> >>>>
> >>>> -Noble
> >>>>
> >>>>
> >>>> On 10/6/06, david robin <robindavi@gmail.com> wrote:
> >>>>
> >>>>
> >>>>
> >>>>> Dear all,
> >>>>> I m confused with neighbor priority command, I configured R1 as
> >>>>> frame-relay
> >>>>> hub, R2 and R5 as spokes. interfaces are non-broadcast so you must
> >>>>>
> > use
> >
> >>>>> neighbor command.
> >>>>>
> >>>>> because R1 is the hub so prioriies of the two other routers must be
> >>>>>
> > set
> >
> >>>>>
> >>>>>
> >>> to
> >>>
> >>>
> >>>>> 0
> >>>>> in order to make R1 as the DR, I know we can accomplish this by
> >>>>>
> > using
> >
> >>>>>
> >>>>>
> >>> ip
> >>>
> >>>
> >>>>> ospf priority 0 under R2 and R5 serial interfaces.
> >>>>>
> >>>>> the question is does the neighbor priority command has any relation
> >>>>>
> > to
> >
> >>>>> DR/BDR election, and if so what is the relation between it and ip
> >>>>>
> > ospf
> >
> >>>>> priority 0, does ospf priority 0 override it or what ?
> >>>>>
> >>>>> and what is the use on neighbor priority command if is has no
> >>>>>
> > relation
> >
> >>>>>
> >>>>>
> >>> to
> >>>
> >>>
> >>>>> DR/BDR election
> >>>>>
> >>>>> many thanks
> >>>>>
> >>>>>
> >>>>>
> > _______________________________________________________________________
> >
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> >>>>>
> >>>>>
> >>>>>
> > _______________________________________________________________________
> >
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> >>>>
> >>>>
> >>
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> >
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