Re: OSPF virtual-link-

Thanks Shane.

On Fri, Oct 5, 2012 at 4:05 AM, Shane Killian <shane_at_shanekillian.net>wrote:

> *discontiguous
>
> On 5 Oct 2012, at 12:02, Imran Ali <immrccie_at_gmail.com> wrote:
>
> > Narbik , i have never heard of area fragmentation. what does it mean?
> >
> > On Fri, Oct 5, 2012 at 6:25 AM, Narbik Kocharians <narbikk_at_gmail.com>
> wrote:
> >
> >> oo IPX,
> >>
> >> The only area that can not be fragmented is area 0.
> >>
> >> On Thu, Oct 4, 2012 at 5:15 PM, oo IPX <oispxl_at_gmail.com> wrote:
> >>
> >>> Thanks for quick answers. In-fact I was trying a virtual-link over an
> >> area
> >>> 0, while trying making non-backbone area contiguous over a V-link (just
> >> for
> >>> curiosity), and got this error into debug that 'source ip address don't
> >>> match'. I guess over area 0 either its not supported or it behaves
> >>> differently, AS for sure the ios allows to use area 0 in the command
> >>> syntax, but how it deals with it later, i don't know :-)
> >>>
> >>> And an interesting thing i noted, when using virtual link over a link
> in
> >>> area 0 with both endpoint on common sub-net is -- as soon as
> >>> one side is configured for the virtual link it starts sending hello
> >> packets
> >>> that don't contain the neighbor router-id, and as the source of the
> hello
> >>> packet is same over which the underlying peering is built on, the other
> >>> router jumps to INIT as soon as the hello packet that don't recognize
> >> this
> >>> router arrives.
> >>> But, I didn't notice this problem in same setup with non-backbone area.
> >>> I know its silly and not required, ( using a v link over backbone)
> >>>
> >>> Can we source the hello packets from different address, not by using
> the
> >>> tunnels.
> >>>
> >>> Thanks
> >>>
> >>> On Fri, Oct 5, 2012 at 5:22 AM, Adam Booth <adam.booth_at_gmail.com>
> wrote:
> >>>
> >>>> Even though the Cisco documentation is generally good , when it comes
> >> to
> >>>> base protocol operation, it's better to look at the RFC for the
> >> protocol,
> >>>> http://www.ietf.org/rfc/rfc2328.txt
> >>>>
> >>>> Section 15 second paragraph
> >>>>
> >>>> The virtual link is treated as if it were an unnumbered point-to-
> >>>> point network belonging to the backbone and joining the two area
> >>>> border routers. An attempt is made to establish an adjacency over
> >>>> the virtual link. When this adjacency is established, the virtual
> >>>> link will be included in backbone router-LSAs, and OSPF packets
> >>>> pertaining to the backbone area will flow over the adjacency
> >>>>
> >>>>
> >>>> virtual-links are configured on a router with the peer being the
> >>>> router-id, which is not necessarily an active IP address
> >>>>
> >>>>
> >>>>
> >>>>
> >>>> On Fri, Oct 5, 2012 at 9:16 AM, oo IPX <oispxl_at_gmail.com> wrote:
> >>>>
> >>>>> Hello,
> >>>>>
> >>>>> how the ospf peering comes up over a virtual link even when the
> source
> >>> ip
> >>>>> address of the uni-cast hello are not on the same subnet ?
> >>>>>
> >>>>> Thanks.
> >>>>>
> >>>>>
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> >>
> >> --
> >> *Narbik Kocharians
> >> *CCSI#30832, CCIE# 12410 (R&S, SP, Security)
> >> *www.MicronicsTraining.com* <http://www.micronicstraining.com/>
> >> Sr. Technical Instructor
> >> YES! We take Cisco Learning Credits!
> >> A Cisco Learning Partner
> >>
> >>
> >> Blogs and organic groups at http://www.ccie.net
> >>
> >> _______________________________________________________________________
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> >
> >
> > Blogs and organic groups at http://www.ccie.net
> >
> > _______________________________________________________________________
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> >
> >
> >
> >
> >
> >
> >
>

-- 
*Narbik Kocharians
*CCSI#30832, CCIE# 12410 (R&S, SP, Security)
*www.MicronicsTraining.com* <http://www.micronicstraining.com/>
Sr. Technical Instructor
YES! We take Cisco Learning Credits!
A Cisco Learning Partner
Blogs and organic groups at http://www.ccie.net