Subject: [OSPF] OSPFv3 virtual link

From: "Goyal, Manoj" <[email-masked]>
Date: Wed, 11 Jul 2007 09:31:37 -0700

Hi,

            C
            |
A------B----------D
                (x)

In the above network, C is DR. I want to setup
a virtual lilnk from A to D. To do so I would need to
get a global address of D to associate with Vlink endpoint.

Here there is only one global address 'x' configured at D at the
broadcast interface shown above.

How will the A know that the 'x' belongs to D ?

The x will appear only in the intra-area-prefix LSA built by
C and there is no indication there that x belongs to D. And A does
not get the link LSA of D.

Is there something I am missing here?

thanks,
Manoj
============================================================
The information contained in this message may be privileged
and confidential and protected from disclosure. If the reader
of this message is not the intended recipient, or an employee
or agent responsible for delivering this message to the
intended recipient, you are hereby notified that any reproduction,
dissemination or distribution of this communication is strictly
prohibited. If you have received this communication in error,
please notify us immediately by replying to the message and
deleting it from your computer. Thank you. Tellabs
============================================================

_______________________________________________
OSPF mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/ospf

---

From: Acee Lindem <[email-masked]>
Date: Wed, 11 Jul 2007 12:59:01 -0400

Hi Manoj,
I'm looking at page 40 in  draft-ietf-ospf-ospfv3-update-16.txt

Internet-Draft                OSPF for IPv6                     May 2007

       Metric field for each of these prefixes is set to the interface's
       output cost.

    o  RTX adds the IPv6 prefixes for any directly attached hosts
       belonging to the area (see Appendix C.7) to the intra-area- 
prefix-
       LSA.

    o  If RTX has one or more virtual links configured through the area,
       it includes one of its global scope IPv6 interface addresses in
       the LSA (if it hasn't already), setting the LA-bit in the
       PrefixOptions field, the PrefixLength to 128, and the Metric  
to 0.
       This information will be used later in the routing calculation so
       that the two ends of the virtual link can discover each other's
       IPv6 addresses.

I believe the second bullet allows you leeway to select any
address in the area and advertise it in your intra-area-prefix=LSA
with the LA-bit set.

Thanks,
Acee
P.S. This document has been through WG last call. I guess I'm going
have to get Abhay to fill out the document shepherding work so we can
get the ADs to review it.