Subject: Re: How could OPSFv3 support IPv4 ?

From: "Manral, Vishwas" <[email-masked]>
Date: Wed, 11 Dec 2002 11:31:48 -0500

Hi Yasu,

I think you missed "Link-LSA" equivalents. I think they would be required
too !!!

Thanks,
Vishwas

-----Original Message-----
From: Yasuhiro Ohara [mailto:[email-masked]]
Sent: Wednesday, December 11, 2002 7:48 PM
To: [email-masked]
Subject: Re: How could OPSFv3 support IPv4 ?

> I am wondering how OSPFv3 could support IPv4.
>
> According to the RFC2740, the 24-bit OSPFv3 options field describes the
> router capabilities. For example, the R-bit and the V6-bit are used in
> order to announce IPv6 forwarding capabilities. However, what's happened
> if this V6-bit is clear ?

RFC2740's section 2.7 gives the exact answer:

      V6-bit specializes the R-bit; if the V6-bit is clear an OSPF
      speaker can participate in OSPF topology distribution without
      being used to forward IPv6 datagrams. If the R-bit is set and the
      V6-bit is clear, IPv6 datagrams are not forwarded but diagrams
      belonging to another protocol family may be forwarded.

In routers do not support other protocol family other than IPv6,
the router having V6-bit off should be treated as a non-working router
from the rest of the network.

> If there would be a V4-bit in order to announce the IPv4 capabilities,
> how could OSPFv3 be extended in order to support IPv4 like Integrated
> ISIS ?

You'll need only to define IPv4 version of Intra-Area-Prefix-LSA,
Inter-Area-Prefix-LSA, AS-External-LSA. Using IPv6 address holding
embedded IPv4 address is another option. I guess IPv4-mapped will be
the right choice semantically in that case, but it may not be
accepted as I saw someone states "IPv4-mapped address should not
appear on the wire" somewhere. I believe it means as IP source or
 destination, though.

regards,
yasu

---

From: Acee Lindem <[email-masked]>
Date: Wed, 11 Dec 2002 14:15:22 -0500

> I think you missed "Link-LSA" equivalents. I think they would be required

Yup. I think these would be needed too. Also, if we were serious about this
I don't think using the IPv4 mapped IPv6 address is the best way to go. It
would be better to have new LSA types for for IPv4 or with an AF and generic
address.

--
Acee

---

From: Vincent Jardin <[email-masked]>
Date: Wed, 11 Dec 2002 20:40:26 +0100

Hi Vishwas,

If we just have some new LSA types instead of the IPv4 mapped IPv6
address, would it be enough to import the OSPFv2 LSA's within OSPFv3 ?

Moreover, it could use the scope feature of OSPFv3.

Vincent

---

From: Yasuhiro Ohara <[email-masked]>
Date: Thu, 12 Dec 2002 11:17:36 +0900

right ;p)

regards,
yasu

From: "Manral, Vishwas" <[email-masked]>
Subject: Re: How could OPSFv3 support IPv4 ?
Date: Wed, 11 Dec 2002 11:31:48 -0500