Subject: [OPSAWG] ipDefaultRouterLifetime for IPv4

From: Raphael Garti <[email-masked]>
Date: Thu, 16 Sep 2010 15:27:04 +0200

I have two questions on ipDefaultRouterLifetime, a mandatory object in 
the compliance statements of rfc 4293:

1. The object description says (p.76): REFERENCE "For IPv6 RFC 2462 
sections 4.2 and 6.3.4

It should be (I think): REFERENCE "For IPv6 RFC 2461sections 4.2 and 
6.3.4, shouldn't it?

2. How can I support ipDefaultRouterLifetime for ipv4 devices? Possible 
values are 0..65535, where 0 means it should be removed and 1..65535 are 
lifetime in secs, all relevant for ipv6, none to ipv4. Am I missing 
something?

Raphael

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From: Juergen Schoenwaelder <[email-masked]>
Date: Thu, 16 Sep 2010 16:24:56 +0200

> It should be (I think): REFERENCE "For IPv6 RFC 2461sections 4.2 and 

Yep, seems the RFC number got messed up. You may want to file an
errata so that this can be tracked easily.
 
> lifetime in secs, all relevant for ipv6, none to ipv4. Am I missing 

It would likely have been good to assign a special meaning to the
value 65535 as "unlimited lifetime". Stretching things a bit (or very
much ;-), an implementation could perhaps claim that a static entry
receives a lifetime update every second and thus never moves away from
the lifetime value 65535...

The issue really is not so much IPv4 vs. IPv6 but static vs dynamic
default router entries. For a static IPv6 default router, you will
also likely not know what to report as ipDefaultRouterLifetime and
ipDefaultRouterPreference. Similarly, DHCP can give me a default
router dynamically for IPv4.

/js

-- 
Juergen Schoenwaelder           Jacobs University Bremen gGmbH
Phone: +49 421 200 3587         Campus Ring 1, 28759 Bremen, Germany
Fax:   +49 421 200 3103         <http://www.jacobs-university.de/>

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From: Raphael Garti <[email-masked]>
Date: Sun, 19 Sep 2010 15:20:54 +0200

> errata so that this can be tracked easily.
raph: Thanks, I filed.
> the lifetime value 65535...
raph: Assuming that dynamic protocols might grant lifetime longer than 
65535,
you could either remove the 0..65535 limitation + make 0xffffffff mean 
unlimited time,
or say that 65535 means 'at least 65535'.

Raphael