Re: late question/comment on vrrp-unified-spec-02: IPv4 equivalence

Hi James, 

I looked at 3768, which references 1256 as info and only refers to it as
one of several ways a host might get an IPv4 address.  As
vrrp-unified-spec-02 was heavily based on 3768 for its IPv4 sections,
this explains why it doesn't discuss this.  Ignoring unified question
for a moment, it looks to me that a 3768 compliant backup not running
1256 of a (3768 compliant) master that was running 1256 could hose a
1256 client.  

The question is what, if anything, to do?  As editor, first I'd like to
do nothing as 3768 was silent.  Failing that, maybe clone 8.2.3 into
8.1.x and mention possibility of 1256?  My understanding is that editor
is in a "waiting for guidance" mode just now; the vrrp list is silent,
so I've copied the necessary folks.  

Thanks,
Steve 

> -----Original Message-----
> From: James Carlson [mailto:[email protected]] 
> Sent: Thursday, October 30, 2008 14:28
> To: Stephen Nadas
> Cc: [email protected]
> Subject: late question/comment on vrrp-unified-spec-02: IPv4 
> equivalence
> 
> I searched the list, and found no mention of this issue.  
> Apologies if my searching-fu is insufficient, and it's 
> already been dealt with, and also because I know that this is 
> an awfully late time to be bringing up a question like this.
> 
> Section 8.2.3 of the I-D goes into detail about handling IPv6 
> Router Advertisements, and that's probably a good thing, but 
> there's no equivalent language for IPv4 in section 8.1.
> 
> IPv4 also has ICMP router discovery, just like IPv6, and it 
> works in much the same way.  A loss of this service would 
> cause an outage for networks reliant on it, just as much as a 
> loss of RA is an outage for IPv6, and even though the 
> fail-over itself "works."  The RDISC entries in existing 
> hosts will age away, and new hosts will be completely in the 
> dark.  Shouldn't the proper operation of RFC 1256 be included?
> 
> In that same vein, it's not actually just ICMP router 
> discovery that may be at issue here.  Different network 
> deployments use different router-to-host signaling mechanisms 
> for basic routing information needed by hosts.  In some 
> cases, for v4 at least, that can be delivered by DHCP.  But 
> in other cases, it might be simple RIP default route 
> advertisements.  It's unclear why, when used as an "output only"
> router discovery mechanism, RIP would be excluded.
> 
> Instead of treating this issue as v6-specific and RDISC-only, 
> might it be better to have a section that explains that all 
> router-to-host configuration signaling needs to be preserved 
> by the current Master?
> (And then, if you like, enumerate some known examples, such 
> as IPv4 and IPv6 RAs.)
> 
> I suspect that naming only IPv6 RAs as an issue could lead to 
> uneven implementation by the unwary.
> 
> -- 
> James Carlson, Solaris Networking              
> <[email protected]>
> Sun Microsystems / 35 Network Drive        71.232W   Vox +1 
> 781 442 2084
> MS UBUR02-212 / Burlington MA 01803-2757   42.496N   Fax +1 
> 781 442 1677
> 
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