why link-local address for ipv6 VRRP

[Huafeng Lu]

Hi, VRRPers,

I'm new to this mail list...

While reading draft-ietf-vrrp-unified-spec-02, I found the virtual IPv6
address to be covered by the virtual router should be a link-local
address. On the VRRP routers that compose the virtual router, the
addresses used to send VRRP advertisements are also link-local. Is there
a reason to require link-local addresses? What's the possibility of
extending this to global addresses?

Thanks.
--
Huafeng
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[G. C.]

Hi Huafeng,

Based on my understanding of the draft, we allow the configuration of global addresses too.

In the VRRP Advertisement packet, the draft states that the first address must be link-local.  The other addresses can be global addresses.

Regards,
Georges Chung

On Wed, Jul 2, 2008 at 6:01 AM, Huafeng Lu <Huafeng.Lv@...> wrote:

Hi, VRRPers,

I'm new to this mail list...

While reading draft-ietf-vrrp-unified-spec-02, I found the virtual IPv6
address to be covered by the virtual router should be a link-local
address. On the VRRP routers that compose the virtual router, the
addresses used to send VRRP advertisements are also link-local. Is there
a reason to require link-local addresses? What's the possibility of
extending this to global addresses?

Thanks.
--
Huafeng
_______________________________________________
vrrp mailing list
vrrp@...
https://www.ietf.org/mailman/listinfo/vrrp

_______________________________________________
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vrrp@...
https://www.ietf.org/mailman/listinfo/vrrp

[Huafeng Lu]

G. C. ??:

> Hi Huafeng,
>
> Based on my understanding of the draft, we allow the configuration of
> global addresses too.
>
> In the VRRP Advertisement packet, the draft states that the first
> address must be link-local.  The other addresses can be global addresses.
>
> Regards,
> Georges Chung

Thanks Georges. In other words, among the "IPvX addresses associated
with the virtual router", at least one must be link-local, right? If so,
why do we have to have a link-local virtual router address? (I think the
all the "IPvX addresses associated with the virtual router" are the
virtual addresses of the virtual router, and these virtual addresses are
to be protected by VRRP, right?)

Thanks.
--
Huafeng

> On Wed, Jul 2, 2008 at 6:01 AM, Huafeng Lu <Huafeng.Lv@...
> <mailto:Huafeng.Lv@...>> wrote:
>
>
>     Hi, VRRPers,
>
>     I'm new to this mail list...
>
>     While reading draft-ietf-vrrp-unified-spec-02, I found the virtual IPv6
>     address to be covered by the virtual router should be a link-local
>     address. On the VRRP routers that compose the virtual router, the
>     addresses used to send VRRP advertisements are also link-local. Is there
>     a reason to require link-local addresses? What's the possibility of
>     extending this to global addresses?
>
>     Thanks.
>     --
>     Huafeng
>     _______________________________________________
>     vrrp mailing list
>     vrrp@... <mailto:vrrp@...>
>     https://www.ietf.org/mailman/listinfo/vrrp
>
>

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[G. C.]

Ideally, the draft would describe this further.  Currently, it not explicitly stated.

One use is for Router Advertisement - a virtual router would have to use the virtual link-local address as the source address.  When a backup router transitions to master and starts sending out RAs, it too would need to use the same source IP address.

Did someone see the need for this address for something else?

Cheers,
Georges

On Thu, Jul 3, 2008 at 1:27 AM, Huafeng Lu <Huafeng.Lv@...> wrote:

G. C. ??:

Hi Huafeng,

Based on my understanding of the draft, we allow the configuration of global addresses too.

In the VRRP Advertisement packet, the draft states that the first address must be link-local.  The other addresses can be global addresses.

Regards,
Georges Chung

Thanks Georges. In other words, among the "IPvX addresses associated with the virtual router", at least one must be link-local, right? If so, why do we have to have a link-local virtual router address? (I think the all the "IPvX addresses associated with the virtual router" are the virtual addresses of the virtual router, and these virtual addresses are to be protected by VRRP, right?)

Thanks.
--
Huafeng

On Wed, Jul 2, 2008 at 6:01 AM, Huafeng Lu <Huafeng.Lv@... <mailto:Huafeng.Lv@...>> wrote:


   Hi, VRRPers,

   I'm new to this mail list...

   While reading draft-ietf-vrrp-unified-spec-02, I found the virtual IPv6
   address to be covered by the virtual router should be a link-local
   address. On the VRRP routers that compose the virtual router, the
   addresses used to send VRRP advertisements are also link-local. Is there
   a reason to require link-local addresses? What's the possibility of
   extending this to global addresses?

   Thanks.
   --
   Huafeng
   _______________________________________________
   vrrp mailing list

   vrrp@... <mailto:vrrp@...>

   https://www.ietf.org/mailman/listinfo/vrrp

_______________________________________________
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vrrp@...
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[Bob Hinden-2]

Hi,

The main reason why the link-local address is the first address is  
because link-local addresses are used extensively in IPv6 neighbor  
discovery.   For example, a host's default route to a router will  
point to the link-local address, not a specific global address of the  
router.  In order for the hosts traffic to switch over to a backup  
router the link-local router of the router must be used by VRRPv6.

If this isn't clear, I suggest that one go and re-read the IPv6  
neighbor discovery and auto-configuration specifications to understand  
how IPv6 uses link-local addresses.  One need to understand ND and  
Auto-config inorder to understand how VRRPv6 works.

Regards,
Bob


On Jul 3, 2008, at 6:51 AM, G. C. wrote:

> Ideally, the draft would describe this further.  Currently, it not  
> explicitly stated.
>
> One use is for Router Advertisement - a virtual router would have to  
> use the virtual link-local address as the source address.  When a  
> backup router transitions to master and starts sending out RAs, it  
> too would need to use the same source IP address.
>
> Did someone see the need for this address for something else?
>
> Cheers,
> Georges
>
> On Thu, Jul 3, 2008 at 1:27 AM, Huafeng Lu <Huafeng.Lv@...> wrote:
> G. C. ??:
>
> Hi Huafeng,
>
> Based on my understanding of the draft, we allow the configuration  
> of global addresses too.
>
> In the VRRP Advertisement packet, the draft states that the first  
> address must be link-local.  The other addresses can be global  
> addresses.
>
> Regards,
> Georges Chung
>
> Thanks Georges. In other words, among the "IPvX addresses associated  
> with the virtual router", at least one must be link-local, right? If  
> so, why do we have to have a link-local virtual router address? (I  
> think the all the "IPvX addresses associated with the virtual  
> router" are the virtual addresses of the virtual router, and these  
> virtual addresses are to be protected by VRRP, right?)
>
> Thanks.
> --
> Huafeng
>
> On Wed, Jul 2, 2008 at 6:01 AM, Huafeng Lu <Huafeng.Lv@... <mailto:Huafeng.Lv@...
> >> wrote:
>
>
>    Hi, VRRPers,
>
>    I'm new to this mail list...
>
>    While reading draft-ietf-vrrp-unified-spec-02, I found the  
> virtual IPv6
>    address to be covered by the virtual router should be a link-local
>    address. On the VRRP routers that compose the virtual router, the
>    addresses used to send VRRP advertisements are also link-local.  
> Is there
>    a reason to require link-local addresses? What's the possibility of
>    extending this to global addresses?
>
>    Thanks.
>    --
>    Huafeng
>    _______________________________________________
>    vrrp mailing list
>    vrrp@... <mailto:vrrp@...>
>
>    https://www.ietf.org/mailman/listinfo/vrrp
>
>
>
>
> _______________________________________________
> vrrp mailing list
> vrrp@...
> https://www.ietf.org/mailman/listinfo/vrrp

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