Re: neighborship in OSPF between different network types.

Whenever I think about OSPF peerings and network types, I always make sure
that both ends agree on the presence of a DR/BDR. Like Scott said it is not
necessarily part of the standard, but it really makes for a BAD day if you
mismatch these. If one side thinks there is a DR and the other does not,
you are going to have a hard time. Always make sure both sides agree on the
presence of a DR/BDR.

On Mon, Sep 14, 2009 at 10:00 AM, Scott Morris <smorris_at_ine.com> wrote:

> You'll see the same thing on a non-broadcast network (like frame) where
> the devices don't all agree about who's the DR. You can, if you don't
> pay attention, end up where one spoke thinks the hub is the DR, but the
> hub thinks the other spoke is the DR. Things get all messed up. :)
>
> But you see it a couple times, and you at least won't be surprised by it
> on the lab!
>
>
>
>
> *Scott Morris*, CCIE/x4/ (R&S/ISP-Dial/Security/Service Provider) #4713,
>
> JNCIE-M #153, JNCIS-ER, CISSP, et al.
>
> JNCI-M, JNCI-ER
>
> evil_at_ine.com
>
>
> Internetwork Expert, Inc.
>
> http://www.InternetworkExpert.com
>
> Toll Free: 877-224-8987
>
> Outside US: 775-826-4344
>
>
> Knowledge is power.
>
> Power corrupts.
>
> Study hard and be Eeeeviiiil......
>
>
>
> Mohamed El Henawy wrote:
> > Thanks Scott ..I labbed it , it was full but nothing in the routing
> > table and also database didn't have any type3 lsa's
> >
> > I never seen this before...
> >
> >
> >
> > ----- Original Message ----- From: "Scott Morris" <smorris_at_ine.com>
> > To: "Mohamed El Henawy" <m.henawy_at_link.net>
> > Cc: "Ali El Moussaoui" <mousawi.ali_at_gmail.com>; "Naufal Jamal"
> > <naufalccie_at_yahoo.in>; <ccielab_at_groupstudy.com>
> > Sent: Monday, September 14, 2009 4:51 PM
> > Subject: Re: neighborship in OSPF between different network types.
> >
> >
> >> Agreement on DR/BDR information (or necessity) is NOT required per the
> >> RFC. That's an oversight in my mind, because it sure as hell matters
> >> for your database! :) And even though you may be in full, and even
> >> though your DBDs have been exchanged (show ip ospf database), you'll see
> >> nothing or limited information "approved" in "show ip route".
> >>
> >>
> >>
> >>
> >> *Scott Morris*, CCIE/x4/ (R&S/ISP-Dial/Security/Service Provider) #4713,
> >>
> >> JNCIE-M #153, JNCIS-ER, CISSP, et al.
> >>
> >> JNCI-M, JNCI-ER
> >>
> >> evil_at_ine.com
> >>
> >>
> >> Internetwork Expert, Inc.
> >>
> >> http://www.InternetworkExpert.com
> >>
> >> Toll Free: 877-224-8987
> >>
> >> Outside US: 775-826-4344
> >>
> >>
> >> Knowledge is power.
> >>
> >> Power corrupts.
> >>
> >> Study hard and be Eeeeviiiil......
> >>
> >>
> >>
> >>
> >>
> >> Mohamed El Henawy wrote:
> >>> Thanks Ali ...I thought that they should not reach Full status
> >>>
> >>>
> >>> ----- Original Message -----
> >>> From: Ali El Moussaoui
> >>> To: Mohamed El Henawy
> >>> Cc: Naufal Jamal ; ccielab_at_groupstudy.com
> >>> Sent: Monday, September 14, 2009 1:42 PM
> >>> Subject: Re: neighborship in OSPF between different network types.
> >>>
> >>>
> >>> Mohamed,
> >>>
> >>> The status is full but they will never exchange routes. Check that R2
> >>> consider R1 as BDR (broadcast network) while R1 didnt go DR/BDR
> >>> election
> >>> process (p2p network). This is due to the incompatibility of network
> >>> types.
> >>>
> >>> As mentioned above once u get 2 compatible networks u can tweak
> >>> the timers
> >>> if needed.
> >>>
> >>> Ali
> >>>
> >>>
> >>> On Mon, Sep 14, 2009 at 12:35 PM, Mohamed El Henawy
> >>> <m.henawy_at_link.net>
> >>> wrote:
> >>>
> >>> I can see status is Full...so whats wrong then
> >>>
> >>>
> >>> ----- Original Message ----- From: "Naufal Jamal"
> >>> <naufalccie_at_yahoo.in>
> >>> To: <ccielab_at_groupstudy.com>
> >>> Sent: Monday, September 14, 2009 10:22 AM
> >>> Subject: neighborship in OSPF between different network types.
> >>>
> >>>
> >>>
> >>>
> >>> HI Guys ,
> >>>
> >>> correct me if I am wrong.
> >>>
> >>> I have two routers R1 and R2 directly connected.Ospf is
> >>> configured on
> >>> them.
> >>>
> >>> R1 's network type is point-to-point and R2 is of broadcast type.
> >>>
> >>> I was bit amazed when the neighborship came up between
> >>> them.then I
> >>> realised
> >>> may be its the same hello/dead timer interval due to which
> >>> they came
> >>> up.they
> >>> became neighbours but not adjacent as they were not exchanging
> >>> routes
> >>> with
> >>> each other.Can some one help me understanding this concept or
> >>> give me a
> >>> link
> >>> for it ?
> >>>
> >>> R2#sh ip ospf ne
> >>> Neighbor ID Pri State Dead Time Address
> >>> Interface
> >>> 1.1.1.1 1 FULL/BDR 00:00:38 1.1.1.1
> >>> FastEthernet0/
> >>> 0
> >>> R2#sh ip ospf net
> >>> R2#sh ip ospf int
> >>> Loopback1 is up, line protocol is up
> >>> Internet Address 10.20.10.1/24, Area 0
> >>> Process ID 1, Router ID 1.1.1.2, Network Type LOOPBACK, Cost: 1
> >>> Loopback interface is treated as a stub Host
> >>> FastEthernet0/0 is up, line protocol is up
> >>> Internet Address 1.1.1.2/24, Area 0
> >>> Process ID 1, Router ID 1.1.1.2, Network Type BROADCAST, Cost: 1
> >>> Transmit Delay is 1 sec, State DR, Priority 1
> >>> Designated Router (ID) 1.1.1.2, Interface address 1.1.1.2
> >>> Backup Designated router (ID) 1.1.1.1, Interface address 1.1.1.1
> >>> Timer intervals configured, Hello 10, Dead 40, Wait 40,
> >>> Retransmit 5
> >>> Hello due in 00:00:02
> >>> Index 1/1, flood queue length 0
> >>> Next 0x0(0)/0x0(0)
> >>> Last flood scan length is 1, maximum is 2
> >>> Last flood scan time is 0 msec, maximum is 0 msec
> >>> Neighbor Count is 1, Adjacent neighbor count is 1
> >>> Adjacent with neighbor 1.1.1.1 (Backup Designated Router)
> >>> Suppress hello for 0 neighbor(s)
> >>>
> >>> R1#sh ip ospf ne
> >>> Neighbor ID Pri State Dead Time Address
> >>> Interface
> >>> 1.1.1.2 1 FULL/ - 00:00:32 1.1.1.2
> >>> FastEthernet0/
> >>> 0
> >>> R1#sh ip ospf int
> >>> FastEthernet0/0 is up, line protocol is up
> >>> Internet Address 1.1.1.1/24, Area 0
> >>> Process ID 1, Router ID 1.1.1.1, Network Type POINT_TO_POINT,
> >>> Cost: 1
> >>> Transmit Delay is 1 sec, State POINT_TO_POINT,
> >>> Timer intervals configured, Hello 10, Dead 40, Wait 40,
> >>> Retransmit 5
> >>> Hello due in 00:00:02
> >>> Index 1/1, flood queue length 0
> >>> Next 0x0(0)/0x0(0)
> >>> Last flood scan length is 1, maximum is 1
> >>> Last flood scan time is 0 msec, maximum is 0 msec
> >>> Neighbor Count is 1, Adjacent neighbor count is 1
> >>> Adjacent with neighbor 1.1.1.2
> >>> Suppress hello for 0 neighbor(s)
> >>>
> >>>
> >>> Thanks,
> >>> Naufal
> >>>
> >>>
> >>> Try the new Yahoo! India Homepage. Click here.
> >>> http://in.yahoo.com/trynew
> >>>
> >>>
> >>> Blogs and organic groups at http://www.ccie.net
> >>>
> >>>
> >>> _______________________________________________________________________
> >>> Subscription information may be found at:
> >>> http://www.groupstudy.com/list/CCIELab.html
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> -------------------------------------------------------------------------
> >>>
> >>> -------
> >>>
> >>>
> >>>
> >>> No virus found in this incoming message.
> >>> Checked by AVG - www.avg.com
> >>> Version: 8.5.409 / Virus Database: 270.13.96/2369 - Release
> >>> Date: 09/14/09
> >>> 05:51:00
> >>>
> >>>
> >>>
> >>> Blogs and organic groups at http://www.ccie.net
> >>>
> >>>
> >>> _______________________________________________________________________
> >>> Subscription information may be found at:
> >>> http://www.groupstudy.com/list/CCIELab.html
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> -----------------------------------------------------------------------------
> >>>
> >>> -
> >>>
> >>>
> >>>
> >>> No virus found in this incoming message.
> >>> Checked by AVG - www.avg.com
> >>> Version: 8.5.409 / Virus Database: 270.13.96/2369 - Release Date:
> >>> 09/14/09
> >>> 05:51:00
> >>>
> >>>
> >>> Blogs and organic groups at http://www.ccie.net
> >>>
> >>> _______________________________________________________________________
> >>> Subscription information may be found at:
> >>> http://www.groupstudy.com/list/CCIELab.html
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >
> >
> >
> --------------------------------------------------------------------------------
> >
> >
> >
> >
> > No virus found in this incoming message.
> > Checked by AVG - www.avg.com
> > Version: 8.5.409 / Virus Database: 270.13.96/2369 - Release Date:
> > 09/14/09 05:51:00
>
>
> Blogs and organic groups at http://www.ccie.net
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
>
>
>
>
>
>
>
>

-- 
Regards,
Joe Astorino - CCIE #24347 R&S
Technical Instructor - IPexpert, Inc.
Cell: +1.586.212.6107
Fax: +1.810.454.0130
Mailto:  jastorino_at_ipexpert.com
Blogs and organic groups at http://www.ccie.net