What is the most standard subnet length on internet

Darryl Dunkin ddunkin at netos.net
Fri Dec 19 05:05:40 UTC 2008

In general, announce what you are allocated from the RIR. The minimum allocation from you will see is a /24.

A couple examples:

If you are allocated a /22, announce the /22. Do not announce anything longer unless you have a requirement to (such as a different origin AS). If you are further allocating a subset of that to a downstream, then a /24 out of that is acceptable as the origin will be different.

-----Original Message-----
From: 정치영 [mailto:lionair at samsung.com] 
Sent: Thursday, December 18, 2008 20:44
To: Suresh Ramasubramanian
Cc: nanog at nanog.org
Subject: Re: Re: What is the most standard subnet length on internet


Yes, I guess my concern is close to the second meaning.

It seems so simple. Currently annoucement of /24 seems to be okey, most upstream providers accept this.
However I wonder if there is any ground rule based on any standard or official recommandation.
If there is some standardized rule about prefix length to be annouced, I will make my bgp & IP allocation policy of 
each data center of my company, and I will be able to more fairly and squarely speak to my customer like this 
"You have to change your server's IP address if you want move your server to other place"  

 Chi-Young Joung
 Email: lionair at samsung.com
 Tel +82 70 7015 0623, Mobile +82 17 520 9193
 Fax +82 70 7016 0031

------- Original Message -------
Sender : Suresh Ramasubramanian<ops.lists at gmail.com> 
Date   : 2008-12-19 12:37 (GMT+09:00)
Title  : Re: What is the most standard subnet length on internet

Chi Young, let me clarify one thing here ..

Do you mean IP allocation as in subnet allocation, swipping in apnic
or through a rwhois server etc?

Or do you mean "what is the minimum subnet size I can announce on the
internet and have other providers not drop it on the floor"?


On Fri, Dec 19, 2008 at 8:10 AM, 정치영 <lionair at samsung.com> wrote:
> Hi everyone,
> I'm going to rebuild IP allocation policy of my company and I am looking for some standard reference for my policy.
> I have already studied some standard like RFC1518, RIPE181, RFC2050 and I got it is very important to maintain hierachy structure.
> However, what I am really wondering is what is the most standard subnet length that always can be guaranteed through Internet. less than /24 bit ?
> I could not find any documents about that, which subnet length is most proper value and pursue internet standard policy ?

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