Re: Address space for individuals
- Date: Sun, 22 May 1994 02:29:07 +0200
On Sat, 21 May 1994 11:27:51 +0200 (MET DST) poole@localhost wrote:
> Assuming we have CIDR-aware software, why should we use the class C
> address space for these small allocations? Wouldn't it be better to
> split up one class A (this would allow 4 million allocations of a 3 bit
> net)?
I see no reason why those VSE's cannot have address space from your
current provider block. Instead of:
193.0.0.0/24 machine-100 company
193.0.1.0/24 machine-10 company
193.0.2.0/24 machine-10 company
193.0.3.0/24 machine-10 company
193.0.4.0/24 machine-10 company
193.0.5.0/24 machine-4 company
you would get something like this:
193.0.0.0/24 machine-100 company
193.0.1.0/28 machine-10 company
193.0.1.16/28 machine-10 company
193.0.1.32/28 machine-10 company
193.0.1.48/28 machine-10 company
193.0.1.64/28 machine-4 company
... and use less than 2 C's instead of 6!
I have seen this work at an ISP here on campus who uses a terminal server
(which covers only one C or so) to connect to many customers who use
leased lines.
Chopping up a class A for this purpose means that each chunk (which then
would be at a different ISP each) needs to be announced separately, which
would break CIDR at large.
Why do you want to use separate address space for that?
(Intermezzo: you do bring up an interesting subject though - once we
run out of the class C address space, we will probably need to chop
up blocks of networks from a class A network just we have done now
with 193.0.0.0/8 and 194.0.0.0/8. I hope that all equipment that
routes to external networks is either classless or knows how to handle
disjunct 'subnets' with different subnet masks correctly...)
My personal interpretation of this all is that there are many l-IR's
who agree that assigning a unique class C to each unconnected network
of two PC's is a bad thing. If they don't connect, private address space
is fine; once they connect, renumbering to fit in a ISP CIDR block
is easy if you have just a few machines and not renumbering would
cause the major routing table explosion which we all fear.
Playing around with this leads to a few more interesting ideas. These
are personal; butcher them down if you don't like them:
- Maybe we should make a point that people who want address space
'so they can connect later' to ask them to make a choice of ISP
first and only THEN get address space (from the provider registry,
that is). If they have a small network, say up to 100 hosts or so,
having them use private address space and renumber once they connect
should not be so bad.
- This would point more work to ISP-registries instead of the L-R registry.
This brings down the work on the L-R registries (who do this for free,
after all), and brings these costs to ISP registries (who might see this
as 'customer service' and thus have justification why their IR-activities
cost effort and money)
- It makes CIDR work better!
> My main problem with supporting "sub-class C" allocations is that
> the local-IR's don't operate in a vaccum. There's a whole system
> of:
>
> - computer manufactureres
>
> - networking equipment companies
>
> - consultants
>
> - literature
>
> that can't be ignored. My experience shows that address allocation
> works best when the applicant already knows what to expect. Since
> the above "information system" has barely caught up with subnetting
> and maybe a bit of CIDR, it's suicidal to change yet another aspect
> of allocation policy essentially in secret.
A large amount of the entities listed above doesn't even know about
Internet commodities like DNS and security. This is, IMHO, an area
of added value of the ISP. How many times did you have to explain
about changing a network from using hosts files or Yellow Plague to DNS,
and tell people how to close their network for external access?
In the cases I have seen, the ISP is, apart from moving bits around,
also the 'interface' to the Internet: providing consultancy, first
contact point in case of connectivity problems, knowing where and
how to file domain information, NACR's and the like. Assigning
sub-class C's could be part of that. No customer-equipment
changes are neccessary!
I think assigning arbitrary size of network space instead of binary
multiples of class C's is simply part of the evolution the Internet
is going though.
Geert Jan
