Subnetting Practices

[Gert Doering]

Hi,

On Sun, Jul 15, 2007 at 11:18:13AM -0700, Roland Dobbins wrote:
> On Jul 15, 2007, at 11:03 AM, Gert Doering wrote:
> 
> >if it's "so many addresses that network administators do not need  
> >to worry about
> >network size" it's large enough that a simplistic implementation  
> >will run
> >into problems.  And then it doesn't matter whether you have 2^10 or
> >2^64 unused addresses on the link.
> 
> I agree wholeheartedly with this sentiment - what to do about it,  
> especially on software platforms, is an interesting question.

Indeed.

If the architecture (ARP or ND on Ethernet) isn't to be changed, there
is not much more you can do except rate-limit the rate of ARP/ND requests
you send, and cpu-limit the amount of resources this can take.

A new architecture *could* work with "periodically refresh ND bindings
with all routers, and all unknown addresses are considered unreachable" 
- but this creates interesting scalability problems on its on, when a 
new router boots up on a large network (and would need to receive
"I am alive!!" announcements from every single host).

Gert Doering
        -- NetMaster
-- 
Total number of prefixes smaller than registry allocations:  113403

SpaceNet AG                        Vorstand: Sebastian v. Bomhard
Joseph-Dollinger-Bogen 14          Aufsichtsratsvors.: A. Grundner-Culemann
D-80807 Muenchen                   HRB: 136055 (AG Muenchen)
Tel: +49 (89) 32356-444            USt-IdNr.: DE813185279