Subject: a question about ULA

From: Lawrence Zou <[email-masked]>
Date: Tue, 08 Aug 2006 16:46:09 +0800

when i read RFC4193,I found it does not mentioned what should do when the
router that produced the ULA global ID  reboot.  
Does it will produce another pseudo-random  global id  or it will  recover
the global id that it produced before it reboot?

I ask this question because i think that in a site,it is very probably that
sometimes  the device have to  be rebooted,  if each time the rebooted
router 
produce a new ULA global id,all devices that attached to the router have to
renumbered , i do not think it is a happy  process.

Best regards,

Lawrence 

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From: Remi Denis-Courmont <[email-masked]>
Date: Tue, 8 Aug 2006 11:57:45 +0300

> the global id that it produced before it reboot?

You are not supposed to change your ULA prefix.
The reason why the specification refers to pseudo-random is to discourage
people from using meaningful values, as these would be much more likely to
collide.

This pseudo-random generation is supposed to be a ONE TIME operation for the
whole entity/network. It should never (or only on very special occasions)
have to change. ULA would be very impractical if these were changing; in
particular, storing addresses in DNS would be quite difficult.

-- 
Remi Denis-Courmont
http://www.simphalempin.com/home/

---

From: Mohacsi Janos <[email-masked]>
Date: Tue, 8 Aug 2006 10:56:01 +0200 (CEST)

> renumbered , i do not think it is a happy  process.

This is not the expected operation. I believe more suitable is: site 
administrator generates a pseudo-random global id and configures on 
the routers. ULA does not give automatic router configuration...
Regards,

Janos Mohacsi
Network Engineer, Research Associate, Head of Network Planning
NIIF/HUNGARNET, HUNGARY
Key 00F9AF98: 8645 1312 D249 471B DBAE  21A2 9F52 0D1F 00F9 AF98

---

From: Lawrence Zou <[email-masked]>
Date: Tue, 08 Aug 2006 17:51:35 +0800

Best regards,

Lawrence  

>-----Original Message-----
>From: Mohacsi Janos [mailto:[email-masked]] 
>Sent: Tuesday, August 08, 2006 4:56 PM
>To: Lawrence Zou
>Cc: [email-masked]
>Subject: Re: a question about ULA
>
>
>
>
>
>> when i read RFC4193,I found it does not mentioned what 
>should do when 
>> the router that produced the ULA global ID  reboot.
>> Does it will produce another pseudo-random  global id  or it will  
>> recover the global id that it produced before it reboot?
>>
>> I ask this question because i think that in a site,it is 
>very probably 
>> that sometimes  the device have to  be rebooted,  if each time the 
>> rebooted router produce a new ULA global id,all devices that 
>attached 
>> to the router have to renumbered , i do not think it is a happy  
>> process.
>
>This is not the expected operation. I believe more suitable 
>is: site administrator generates a pseudo-random global id and 
>configures on the routers. ULA does not give automatic router 
>configuration...
>Regards,

yes, i agree with you that maybe it will be more suitable  the pseudo-random
global id be generated by the administrator and configure on the router. so
when the router reboot ,it will got  the same configuration and not cause
the renumbering process.

so , is this the common concept  in IPV6 WG about who  produce  the
pseudo-random global id ?  I did not see it in  the RFC4193 ,or maybe i
missed someting.
thanks .
>NIIF/HUNGARNET, HUNGARY Key 00F9AF98: 8645 1312 D249 471B DBAE 
> 21A2 9F52 0D1F 00F9 AF98
>
>

---

From: Lawrence Zou <[email-masked]>
Date: Tue, 08 Aug 2006 20:36:42 +0800

thanks for your answer.
I have not written code for this. I am working  on how to deploy IPV6 VPN
and I want to use ULA in the VPN site 
to make the VPN gateway can make distinguish between the data flow of
VPN--VPN  and VPN--internet.

Best regards,

Lawrence  

>From: Brian E Carpenter [mailto:[email-masked]] 
>Sent: Tuesday, August 08, 2006 7:15 PM
>To: Lawrence Zou
>Cc: 'Mohacsi Janos'; [email-masked]
>Lawrence Zou wrote:
>> yes, i agree with you that maybe it will be more suitable  the 
>> pseudo-random global id be generated by the administrator and 
>> configure on the router. so when the router reboot ,it will got  the 
>> same configuration and not cause the renumbering process.
>> 
>> pseudo-random global id ?  I did not see it in  the RFC4193 
>,or maybe 
>> i missed someting.
>> thanks .
>
>Section 4.6 says:
>
>    In order for hosts to autoconfigure Local IPv6 addresses, routers
>    have to be configured to advertise Local IPv6 /64 prefixes 
>in router
>    advertisements, or a DHCPv6 server must have been configured to
>    assign them.  In order for a node to learn the Local IPv6 
>address of
>    another node, the Local IPv6 address must have been installed in a
>    naming system (e.g., DNS, proprietary naming system, etc.) 
> For these
>    reasons, controlling their usage in a site is straightforward.
>
>To me this makes it clear that the prefix is static and is 
>configured into routers, DHCP servers, and DNS tables as 
>necessary. I assume that the site manager will just run the 
>algorithm in section 3.2.2 once.
>BTW, has anybody written code for this? It would be a nice 
>little tool to have on a web site.
>
>      Brian
>

---

From: Brian E Carpenter <[email-masked]>
Date: Tue, 08 Aug 2006 13:14:32 +0200

Section 4.6 says:

    In order for hosts to autoconfigure Local IPv6 addresses, routers
    have to be configured to advertise Local IPv6 /64 prefixes in router
    advertisements, or a DHCPv6 server must have been configured to
    assign them.  In order for a node to learn the Local IPv6 address of
    another node, the Local IPv6 address must have been installed in a
    naming system (e.g., DNS, proprietary naming system, etc.)  For these
    reasons, controlling their usage in a site is straightforward.

To me this makes it clear that the prefix is static and is configured
into routers, DHCP servers, and DNS tables as necessary. I assume that
the site manager will just run the algorithm in section 3.2.2 once.
BTW, has anybody written code for this? It would be a nice little
tool to have on a web site.

      Brian

---

From: SUZUKI Shinsuke <[email-masked]>
Date: Wed, 09 Aug 2006 18:49:31 +0900

>>>>> On Tue, 08 Aug 2006 13:14:32 +0200
>>>>> [email-masked](Brian E Carpenter)  said:

> tool to have on a web site.

A shell script is written by Holger Zuleger.
	http://www.hznet.de/tools/generate-rfc4193-addr

And I've written a small CGI based on that.
	http://www.kame.net/~suz/gen-ula.html

Thanks,
----
SUZUKI, Shinsuke @ KAME Project

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From: Brian Haberman <[email-masked]>
Date: Wed, 9 Aug 2006 14:35:20 -0400

I actually put a script together to generate the prefix during the IETF 
in Montreal.  I handed that code to someone who is planning on making 
it available on a web page "real soon".

Regards,
Brian