Re: comment for draft-ietf-vrrp-unified-spec-00

Hi Steve,

Here's my understanding of the problem...

RFC 4861 describes the concept of Advertising Interface (Section 6.2.2).  As
such an an advertising interface that belongs to a router would send out RAs
with the interface's link-local address (LLA) as the source, and the
interface MAC address as the source link-layer option.

Consider the case where the interface owns addresses that would be
advertised in a VRRP Advertisement.  This interface would then send out one
RA as indicated in the previous paragraph and, based on draft 02, another
one using the interface's LLA as the source address (since it's the address
owner) and the virtual MAC address as the source link-layer option.

Now, from the point of view of the host that receives these RAs:  RFC 4861
Section 6.3.4 indicates that the host may update its Neighbor Cache with the
link-layer address included in the RA.  Since the 2 RAs described above
would indicate different link-layer addresses for the same IP address, the
host's ND cache would be constantly be updated back and forth with these
addresses.

Regards,
Georges


On Tue, Jun 3, 2008 at 10:01 AM, Stephen Nadas <[email protected]>
wrote:

>  Georges, Tomohiko,
>
> I do not see in 2461 the words "master" or "backup" so it is not clear to
> me what exactly is meant by Tomohiko's when he says (from below):
>
> > In other hand, according to RFC 2461, both Master and Backup
> > routers are also able to send RA packets for themselves,
> > whose source address is their interface IPv6 link-local
> > address, and source link-layer address option is their
> > interface MAC address.
>
> master and backup routers are VRRP terms - so I think I do not agree with
> the above as I would expect VRRP routers to use VRRP Virtual MACs.
>
> Thanks,
> Steve
>
>  ------------------------------
> *From:* Georges Chung [mailto:[email protected]]
> *Sent:* Monday, June 02, 2008 5:25 PM
> *To:* Stephen Nadas
> *Subject:* Re: [VRRP] RE: comment for draft-ietf-vrrp-unified-spec-00
>
> Hi Steve,
>
> I now realize that I may have missed the boat on this one.
>
> My email's subject line reflected Tomohiko's original email subject line.
> I'm afraid draft -02 still does not specify what to do in the situation
> described by Tomohiko.
>
> Regards,
> Georges
>
>
> On Mon, Jun 2, 2008 at 11:40 AM, Stephen Nadas <[email protected]>
> wrote:
>
>>  Hi Georges,
>>
>> I am a bit confused here - draft is at -02 and went thru wg last call.  Is
>> the current text in -02 satisfactory or not?
>>
>> Thanks,
>> Steve
>>
>>  ------------------------------
>> *From:* [email protected] [mailto:[email protected]] *On Behalf
>> Of *Georges Chung
>> *Sent:* Monday, June 02, 2008 9:33 AM
>> *To:* [email protected]
>> *Subject:* [VRRP] RE: comment for draft-ietf-vrrp-unified-spec-00
>>
>>   I think Tomohiko has a point.
>>
>> Sending a Router Advertisement with the interface's MAC as the source
>> link-layer address would refresh the hosts' Neighbor Cache entry with the
>> router's physical MAC address.  We want the hosts to use the virtual MAC
>> address of the router instead.
>>
>> Can the draft be updated with this?
>>
>> Thanks,
>> Georges
>>
>>
>>
>> ----------------------------------------------------------------------------------------
>>
>> Hello Tomohiko,
>>
>> Thank you for your comment.  I am copying to the vrrp list as well for
>>
>>
>> any comments WG may have.
>>
>> Regards,
>> Steve
>>
>> > -----Original Message-----
>> > From: kura at iij.ad.jp [mailto:kura <kura> at iij.ad.jp]
>>
>>
>> > Sent: Wednesday, January 23, 2008 12:54 AM
>> > To: Stephen Nadas
>> > Subject: comment for draft-ietf-vrrp-unified-spec-00
>> >
>> > Hello,
>> >
>> > This is Tomohiko Kurahashi from IIJ which is an ISP in Japan.
>>
>>
>> > I have a comment for draft-ietf-vrrp-unified-spec-00, with
>> > regard to the interaction with IPv6 Router Advertisements (RAs).
>> >
>> > According to the draft, Master router (only) sends RA packets
>>
>>
>> > for a virtual router, whose source address is the IPv6
>> > link-local address associated with the virtual router (e.g.
>> > link-local address of address owner), and source link-layer
>> > address option is the virtual router MAC address.
>>
>>
>> >
>> > In other hand, according to RFC 2461, both Master and Backup
>> > routers are also able to send RA packets for themselves,
>> > whose source address is their interface IPv6 link-local
>> > address, and source link-layer address option is their
>>
>>
>> > interface MAC address.
>> >
>> > Under such situation that both kinds of RAs mentioned above
>> > are being advertised, some hosts receiving former (first) may
>> > set their default route to the virtual router, and others
>>
>>
>> > receiving latter (first) may set to one of real routers. This
>> > must be an unwilling result for network managers/administrators.
>> >
>> > I think it should be mentioned explicitly in the draft that
>>
>>
>> > VRRP routers MUST stop advertising the latter kind of RAs
>> > automatically (or by configuration).
>> >
>> > FYI, the following is Cisco manual of HSRP for IPv6.
>> > http://www.cisco.com/en/US/products/ps6350/products_configurat
>>
>>
>> > ion_guide_chapter09186a008078f345.html#wp1066077
>> >
>> > I'm glad if you take my comment into consideration.
>> >
>> > Best regards,
>> > --
>> > Tomohiko Kurahashi <kura at iij.ad.jp>
>>
>>
>> > Internet Initiative Japan Inc.
>>
>>
>>
>

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