Re: Re: What is the most standard subnet length on internet

[정치영]

Suresh,

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"  

chiyoung
=
 Chi-Young Joung
 SAMSUNG NETWORKS Inc.
 Email: lion...@samsung.com
 Tel +82 70 7015 0623, Mobile +82 17 520 9193
 Fax +82 70 7016 0031
=

--- Original Message ---
Sender : Suresh Ramasubramanian 
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"?

srs

On Fri, Dec 19, 2008 at 8:10 AM, 정치영  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 ?
>

RE: Re: What is the most standard subnet length on internet

[Darryl Dunkin]

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

A couple examples:
http://www.arin.net/reference/ip_blocks.html#ipv4
https://www.ripe.net/ripe/docs/ripe-ncc-managed-address-space.html

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:lion...@samsung.com] 
Sent: Thursday, December 18, 2008 20:44
To: Suresh Ramasubramanian
Cc: nanog@nanog.org
Subject: Re: Re: What is the most standard subnet length on internet

Suresh,

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"  

chiyoung
=
 Chi-Young Joung
 SAMSUNG NETWORKS Inc.
 Email: lion...@samsung.com
 Tel +82 70 7015 0623, Mobile +82 17 520 9193
 Fax +82 70 7016 0031
=

--- Original Message ---
Sender : Suresh Ramasubramanian 
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"?

srs

On Fri, Dec 19, 2008 at 8:10 AM, 정치영  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 ?
>

Re: Re: What is the most standard subnet length on internet

[Suresh Ramasubramanian]

Even if a longer prefix like a /24 is announced, chances of people
accepting it is slim.   Especially, as you say, if the RIR allocation
is something larger than /24

And I have a feeling acceptance /24 route announcements of anything
other than legacy classful space, infrastructure space like the root
servers is going to be patchy at best.

2008/12/19 Darryl Dunkin :
>
> 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.
>

Re: Re: What is the most standard subnet length on internet

[Patrick W. Gilmore]

Even if a longer prefix like a /24 is announced, chances of people
accepting it is slim.   Especially, as you say, if the RIR allocation
is something larger than /24

And I have a feeling acceptance /24 route announcements of anything
other than legacy classful space, infrastructure space like the root
servers is going to be patchy at best.

2008/12/19 Darryl Dunkin :


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.

Re: Re: What is the most standard subnet length on internet

[정치영]

Hi all, 

I appreciate many people gave me advices,
Some of persons asked me about my questions, I'm sorry for that I couldn't 
reply to everyone.
Because of your help, I could get many opinions and standards regarding IP 
allocation policy.
 
by the way, in APNIC's IP allocation sizes policy, there is a comments like 
below.
"Below are the minimum sizes for allocations and assignments, This information 
is provided at the request of the ISP community
to assist in filtering policy decisions "
Currently, is there any provider filtering routes under LIR's minimum 
allocation size such as /22 ? 

Best regards,
=
 Chi-Young Joung
 SAMSUNG NETWORKS Inc.
 Email: lion...@samsung.com
 Tel +82 70 7015 0623, Mobile +82 17 520 9193
 Fax +82 70 7016 0031
=

--- Original Message ---
Sender : Danny McPherson 
Date   : 2008-12-21 02:42 (GMT+09:00)
Title  : Re: What is the most standard subnet length on internet


On Dec 18, 2008, at 9:43 PM, 정치영 wrote:

> Suresh,
>
> 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"

Some useful guidance is provided here (and in
subsequent references) as well:

An Architecture for IP Address Allocation with CIDR


Classless Inter-Domain Routing (CIDR): an Address Assignment and  
Aggregation Strategy


Network Renumbering Overview


A Framework for Inter-Domain Route Aggregation


HTH,

-danny

Re: Re: What is the most standard subnet length on internet

[ChiYoung Joung]

I would like to ask question more specifically.

I know most of tier1 providers accept their customer prefixes smaller than /24.
it means smaller than /24 routes always routable in that Tier1 provider.
What about between Tier1 and another Tier1 ?  
Do they exchange their full customer's routes without any limitation of 
prefixes length ?
or do they refer to some DB information like Regional Internet Registry and 
apply another filter on neighbor configuration with another Tier1 ?  

Chiyoung
=
 Chi-Young Joung
 SAMSUNG NETWORKS Inc.
 Email: lion...@samsung.com
 Tel +82 70 7015 0623, Mobile +82 17 520 9193
 Fax +82 70 7016 0031
=

--- Original Message ---
Sender : Nathan Ward 
Date   : 2008-12-23 10:44 (GMT+09:00)
Title  : Re: What is the most standard subnet length on internet

On 23/12/2008, at 2:39 PM, Joe Provo wrote:

> On Tue, Dec 23, 2008 at 02:34:39PM +1300, Nathan Ward wrote:
> [snip]
>> Let me rephrase; Are there people who are filtering /24s received  
>> from
>> eBGP peers who do not have a default route?
>
> of course.


Curiously, it was really meant as a rhetorical question where the  
answer was "no".

Why are people doing this? Are they lacking clue, or, is there some  
reasonable purpose?

--
Nathan Ward

Fwd: Re: Re: What is the most standard subnet length on internet

[정치영]

"You have to change your server's IP address if you want move your server to 
other place"  

 -> It is very natural case, but some customer could think of it will be okey 
to move if they have C class.
but I have different idea. because the border router of that center is 
annoucing more greater IP block,
and if customer move to other center with C class, then I have to newly 
announce that C class at the border router of other center.
and then it is the time my hierachy structure is broken.  
To prevent this situation, I'm trying to find some standard material every 
person would understand and accept.

=
 Chi-Young Joung
 SAMSUNG NETWORKS Inc.
 Email: lion...@samsung.com
 Tel +82 70 7015 0623, Mobile +82 17 520 9193
 Fax +82 70 7016 0031
=

--- Original Message ---
Sender : 정치영  과장/기술1팀/삼성네트웍스
Date   : 2008-12-19 13:43 (GMT+09:00)
Title  : Re: Re: What is the most standard subnet length on internet

Suresh,

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"  

chiyoung
=
 Chi-Young Joung
 SAMSUNG NETWORKS Inc.
 Email: lion...@samsung.com
 Tel +82 70 7015 0623, Mobile +82 17 520 9193
 Fax +82 70 7016 0031
=

--- Original Message ---
Sender : Suresh Ramasubramanian 
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"?

srs

On Fri, Dec 19, 2008 at 8:10 AM, 정치영  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 ?
>

Re: Fwd: Re: Re: What is the most standard subnet length on internet

[Howard C. Berkowitz]

I may not completely understand your concerns, especially about customers
moving. I would, however, strongly encouraging not using the terms A,B or
C in NANOG discussions; I've found they lead to assumptions based on
obsolete ideas.

Let's assume an enterprise has had one transit provider, who is in the
default-free zone.  Working together, the customer and provider agreed the
customer needed a /23, and the provider assigns 1.0.0.0/23 as a PA subpart
of its own space. 1.0.0.0/8. Using RFC 1998 techniques, for load sharing
at four POPs of that same provider, that customer then announces, at each
POP, a /25 reflecting the /25 used for machines in the local area of that
POP, but also announces the /23. With a single provider, the RFC1998
method applies, and the routes announced are tagged with NO-EXPORT.  As
long as the enterprise is not multihomed, its more-specifics will be
handled properly by provider A's announcement of 1.0.0.0/8?

Now, assume that customer gets a single link to a different provider B,
whose PI space is 2.0.0.0/8. For multihoming to work, at least two things
start to happen. Both providers A and B need to announce 1.0.0.0/23 to the
rest of the Internet. If only provider B advertised (2.0.0.0/8,
1.0.0.0/23) to the rest of the internet, all traffic to the enterprise
would come through provider B, because it announces a more-specific. For
the traffic to work, BOTH A and B have to announce 1.0.0.0/23, so other
providers, with full routes, spread load to the two providers.

The enterprise can still announce both /23 and /25 to Provider A, with
NO-EXPORT on the /25's, because Provider A can make use of the /25 to
better manage traffic to its POPs.  Administratively, Providers A and B
have to agree to Provider B advertising a piece of Provider A's space.

Am I answering the question you are asking?


Á¤Ä¡¿µ wrote:
> "You have to change your server's IP address if you want move your server
> to other place"
>
>  -> It is very natural case, but some customer could think of it will be
> okey to move if they have C class.
> but I have different idea. because the border router of that center is
> annoucing more greater IP block,
> and if customer move to other center with C class, then I have to newly
> announce that C class at the border router of other center.
> and then it is the time my hierachy structure is broken.
> To prevent this situation, I'm trying to find some standard material every
> person would understand and accept.
>
> =
>  Chi-Young Joung
>  SAMSUNG NETWORKS Inc.
>  Email: lion...@samsung.com
>  Tel +82 70 7015 0623, Mobile +82 17 520 9193
>  Fax +82 70 7016 0031
> =
>
> --- Original Message -------
> Sender : Á¤Ä¡¿µ  °úÀå/±â¼ú1ÆÀ/»ï¼º³×Æ®¿÷½º
> Date   : 2008-12-19 13:43 (GMT+09:00)
> Title  : Re: Re: What is the most standard subnet length on internet
>
> Suresh,
>
> 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"
>
> chiyoung
> =
>  Chi-Young Joung
>  SAMSUNG NETWORKS Inc.
>  Email: lion...@samsung.com
>  Tel +82 70 7015 0623, Mobile +82 17 520 9193
>  Fax +82 70 7016 0031
> =
>
> --- Original Message ---
> Sender : Suresh Ramasubramanian
> 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"?
>
> srs
>
> On Fri, Dec 19, 2008 at 8:10 AM, Á¤Ä¡¿µ  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 ?
>>
>
>
>
>
>