internet ip addressing

Hi, with regards to /31 addressing on point to point links. I have not
seen any real world examples using this type of addressing scheme, only
/30.

Are there any examples of real world 'internet routers' using /31? How
do large organizations
address point to point links?

thx jason

On 31 Aug 2006 09:16:03 -0700
"jasonsig" <(E-Mail Removed)> wrote:

> Hi, with regards to /31 addressing on point to point links. I have not
> seen any real world examples using this type of addressing scheme,
> only /30.
>
> Are there any examples of real world 'internet routers' using /31? How
> do large organizations
> address point to point links?

They use the /30.

With /31 you have the following addresses:

192.168.0.0 = network address
192.168.0.1 = first host address
192.168.0.2 = gateway address
192.168.0.3 = broadcast address

Humm we can't fit all that in the /31 can we, as we only have the first
two available addresses. Granted one can put the gateway on the
broadcast address, but we cannot do that since /31 does not give room
for this.

We cannot put the gateway on the network address, it would just confuse
the hell out of the hosts.

If you *can* set this up, I'd be very surprised. Nearly all ISPs will
use a /30 for their routing equipment, if this equipment is on their
core/backbone network then they will use a larger subnet, perhaps /26 or
/27 for a small second of their devices, but then put /24's in their
customer networks, the routing tables have to be correctly configured
for this so that those network blocks are routed via their core. This is
generally how PTP (Point To Point) routing works. The internet is not
beautifully constructed, network blocks don't traverse down the routing
tree geographically.

--
Regards, Ed :: http://www.openbsdhacker.com
proud unix person
Email sent from Vin Diesel is composed in haiku form.

Hi, what would you make of rfc3021 ?

thx jason

ed wrote:
> On 31 Aug 2006 09:16:03 -0700
> "jasonsig" <(E-Mail Removed)> wrote:
>
> > Hi, with regards to /31 addressing on point to point links. I have not
> > seen any real world examples using this type of addressing scheme,
> > only /30.
> >
> > Are there any examples of real world 'internet routers' using /31? How
> > do large organizations
> > address point to point links?
>
> They use the /30.
>
> With /31 you have the following addresses:
>
> 192.168.0.0 = network address
> 192.168.0.1 = first host address
> 192.168.0.2 = gateway address
> 192.168.0.3 = broadcast address
>
> Humm we can't fit all that in the /31 can we, as we only have the first
> two available addresses. Granted one can put the gateway on the
> broadcast address, but we cannot do that since /31 does not give room
> for this.
>
> We cannot put the gateway on the network address, it would just confuse
> the hell out of the hosts.
>
> If you *can* set this up, I'd be very surprised. Nearly all ISPs will
> use a /30 for their routing equipment, if this equipment is on their
> core/backbone network then they will use a larger subnet, perhaps /26 or
> /27 for a small second of their devices, but then put /24's in their
> customer networks, the routing tables have to be correctly configured
> for this so that those network blocks are routed via their core. This is
> generally how PTP (Point To Point) routing works. The internet is not
> beautifully constructed, network blocks don't traverse down the routing
> tree geographically.
>
> --
> Regards, Ed :: http://www.openbsdhacker.com
> proud unix person
> Email sent from Vin Diesel is composed in haiku form.

On 09/01/2006 01:28 AM, ed wrote:
> They use the /30.
>
> With /31 you have the following addresses:
>
> 192.168.0.0 = network address
> 192.168.0.1 = first host address
> 192.168.0.2 = gateway address
> 192.168.0.3 = broadcast address

The above can only be achieved with /30, if I'm not wrong /31 as a mask
leaves only 1 bit for the host addresses ...

192.168.0.0/31 will/can give only 2 ip addresses:

192.168.0.0 = First host address
192.168.0.1 = Last/Max host address

No broadcast address, no network address; these are not needed for PtP
connections. PtP links are just links, and are not networks.

And /30 gives us smallest possible TCP/IP (sub)network.

--
Dr Balwinder S "bsd" Dheeman Registered Linux User: #229709
Anu's Linux@HOME Machines: #168573, 170593, 259192
Chandigarh, UT, 160062, India Distros: Ubuntu, Fedora, Knoppix
Home: http://cto.homelinux.net/~bsd/ Visit: http://counter.li.org/

On 31 Aug 2006, in the Usenet newsgroup comp.os.linux.networking, in article
<(E-Mail Removed). com>, jasonsig wrote:

>Hi, what would you make of rfc3021 ?

comp.protocols.tcp-ip TCP and IP network protocols.

>>> Hi, with regards to /31 addressing on point to point links. I have not
>>> seen any real world examples using this type of addressing scheme,
>>> only /30.

Can't say that I have either. Please don't top post.

Old guy

With regards to 'old guy'. I believe my question was still related to
'networking'. As for the top post my Apologies.

js

Moe Trin wrote:
> On 31 Aug 2006, in the Usenet newsgroup comp.os.linux.networking, in article
> <(E-Mail Removed). com>, jasonsig wrote:
>
> >Hi, what would you make of rfc3021 ?
>
> comp.protocols.tcp-ip TCP and IP network protocols.
>
> >>> Hi, with regards to /31 addressing on point to point links. I have not
> >>> seen any real world examples using this type of addressing scheme,
> >>> only /30.
>
> Can't say that I have either. Please don't top post.
>
> Old guy

jasonsig wrote:
> With regards to 'old guy'. I believe my question was still related to
> 'networking'. As for the top post my Apologies.

FUCKING hilarious!

Hey ! We've got a live one !

>
> js
>
> Moe Trin wrote:
>> On 31 Aug 2006, in the Usenet newsgroup comp.os.linux.networking, in article
>> <(E-Mail Removed). com>, jasonsig wrote:
>>
>>> Hi, what would you make of rfc3021 ?
>> comp.protocols.tcp-ip TCP and IP network protocols.
>>
>>>>> Hi, with regards to /31 addressing on point to point links. I have not
>>>>> seen any real world examples using this type of addressing scheme,
>>>>> only /30.
>> Can't say that I have either. Please don't top post.
>>
>> Old guy
>

jasonsig wrote:
> Hi, with regards to /31 addressing on point to point links. I have not
> seen any real world examples using this type of addressing scheme

That would be because it is impossible.

The minimum number of adresses needed for a valid subnet is 3.

(1 network, 1 host, 1 gateway)

On Mon, 04 Sep 2006, in the Usenet newsgroup comp.os.linux.networking, in
article <uiaus3-(E-Mail Removed)>, Jeroen Geilman wrote:

>jasonsig wrote:

>> Hi, with regards to /31 addressing on point to point links. I have not
>> seen any real world examples using this type of addressing scheme

>That would be because it is impossible.
>
>The minimum number of adresses needed for a valid subnet is 3.
>
>(1 network, 1 host, 1 gateway)

Open mouth - insert foot. Free hint:

3021 Using 31-Bit Prefixes on IPv4 Point-to-Point Links. A. Retana, R.
White, V. Fuller, D. McPherson. December 2000. (Format: TXT=19771
bytes) (Status: PROPOSED STANDARD)

HTH, HAND,

Old guy

On 3 Sep 2006, in the Usenet newsgroup comp.os.linux.networking, in article
<(E-Mail Removed) .com>, jasonsig wrote:

>With regards to 'old guy'. I believe my question was still related to
>'networking'.

That's why I suggested comp.protocols.tcp-ip, which is where something
like this is discussed. The group isn't all that high in traffic, and
looking at the last 30 days of posting (which you should do before
posting to understand _any_ newsgroup) is about 340 articles, or about 10
a day. The "List of Big Eight Newsgroups" that is posted to the newsgroups
news.announce.newgroups, news.groups, and news.lists.misc on the 15th of
every month gives fairly valuable clues as to the appropriate group to
pose a question. Examples:

comp.os.linux.networking Networking and communications under Linux.
comp.protocols.tcp-ip TCP and IP network protocols.

This group is aimed at Linux networking, while the other is aimed at
TCP/IP networking in general. I'm not even sure that the Linux networking
code is aware of the trick needed in RFC3021, while routers (especially
from Cisco) are (given that the author is from Cisco).

comp.dcom.sys.cisco Info on Cisco routers and bridges.

That might be another good group to review.

>As for the top post my Apologies.

Yeah - a hint from the newsgroup FAQ posted twice a week to alt.os.linux,
comp.os.linux.misc, and comp.os.linux.setup among others:

"Google Groups users please read - Howto reply properly"
http://groups.google.com/support/bin...y?answer=14213

as well as

"What is Usenet?"
http://www.faqs.org/faqs/usenet/what-is/part1/

"The Usenet Newbie Project"
http://tgos.org/newbie/index2.html

"Eric S. Raymond (ESR) & Rick Moen:
How To Ask Questions The Smart Way?"
http://catb.org/~esr/faqs/smart-questions.html

Otherwise, you're just digging your own hole.

Old guy