Re: Unique Local Address (ULA) - IPv6

Scott/Joe, thanks for your replies :)

2009/12/16 Joe Astorino <jastorino_at_ipexpert.com>

> Whoops...means subnetted into two /8's of course : )
>
>
> On Wed, Dec 16, 2009 at 12:25 AM, Joe Astorino <jastorino_at_ipexpert.com>wrote:
>
>> It is somewhat strange.
>>
>> Essentially they took the FC00::/7 range and subnetted into two /7s --
>> FC00::/8 and FD00::/8. Each /8 is for a different purpose. Basically we
>> have two different things because different people have different views on
>> how things should be done.
>>
>> With FC00::/8 range your site-local address is actually ASSIGNED to you by
>> a registrar even though the range is NOT globally routable. This ensures
>> that everything remains unique within your organization. There is actually
>> accountability where there is an organization that assigns to you your
>> locally used ranges
>>
>> With FD00::/8 it is more like RFC1918 space, where your site-ID is a
>> "semi-randomly" generated number, and you have 16 bits for subnetting left
>> which effectively gives you room for like 65,535 /64 subnets to play with :
>> )
>>
>> So FC00::/8 looks something like this where the 40-bit global-id (your
>> "site ID") is ASSIGNED to you
>>
>> [FC][Global-ID][Subnet-ID][Interface ID]
>> [8 ] [40 bits ][16 bits ]]64 bits ]
>>
>> The FD00::/8 stuff would look essentially the same, except the 40-bit
>> global-id is NOT assigned to you...it is randomly generated
>>
>> HTH
>>
>> P.S. This is not to be confused with "site-local" addressing (FEC0::/10)
>> which is depricated. The reason behind this being depricated has to do with
>> many many arguments over the ambiguity of what is considered a "site".
>>
>>
>> On Tue, Dec 15, 2009 at 7:14 PM, Scott Morris <smorris_at_ine.com> wrote:
>>
>>> You'd configure it where the lab told you. :)
>>>
>>> If it said "you have been assigned an ID of ..." then I'd use FC. If it
>>> said "you decided to use an ID of ...." then I'd use FD.
>>>
>>> HTH,
>>>
>>>
>>>
>>>
>>> *Scott Morris*, CCIE/x4/ (R&S/ISP-Dial/Security/Service Provider) #4713,
>>>
>>> JNCIE-M #153, JNCIS-ER, CISSP, et al.
>>>
>>> JNCI-M, JNCI-ER
>>>
>>> evil_at_ine.com
>>>
>>>
>>> Internetwork Expert, Inc.
>>>
>>> http://www.InternetworkExpert.com
>>>
>>> Toll Free: 877-224-8987
>>>
>>> Outside US: 775-826-4344
>>>
>>>
>>> Knowledge is power.
>>>
>>> Power corrupts.
>>>
>>> Study hard and be Eeeeviiiil......
>>>
>>>
>>>
>>> Roy Waterman wrote:
>>> > Hi all
>>> >
>>> > Would like some clarification on configuring ulas.
>>> > We all know its: FC00::/7, however as per RFC4193 it mentions that the
>>> L bit
>>> > (the 8th bit) is set to 1 if the prefix is locally assigned, and that L
>>> bit
>>> > as 0 is undefined.
>>> > As such in various places, Ive seen that you'd typically configure ulas
>>> > starting as fd00::/8, but from a Cisco implementation perspective,
>>> > does it matter whether fc00::/8 or fd00::/8 is used?
>>> >
>>> > >From a lab perspective, if asked to configure a ula, should ipv6
>>> address
>>> > fd00:... always be used (locally assigning the ipv6 address) ?
>>> >
>>> > Please advise.
>>>
>>>
>>> Blogs and organic groups at http://www.ccie.net
>>>
>>> _______________________________________________________________________
>>> Subscription information may be found at:
>>> http://www.groupstudy.com/list/CCIELab.html
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>
>>
>> --
>> Regards,
>>
>> Joe Astorino CCIE #24347 (R&S)
>> Sr. Technical Instructor - IPexpert
>> Mailto: jastorino_at_ipexpert.com
>> Telephone: +1.810.326.1444
>> Live Assistance, Please visit: www.ipexpert.com/chat
>> eFax: +1.810.454.0130
>>
>> IPexpert is a premier provider of Classroom and Self-Study Cisco CCNA
>> (R&S, Voice & Security), CCNP, CCVP, CCSP and CCIE (R&S, Voice, Security &
>> Service Provider) Certification Training with locations throughout the
>> United States, Europe and Australia. Be sure to check out our online
>> communities at www.ipexpert.com/communities and our public website at
>> www.ipexpert.com
>>
>>
>>
>
>
> --
> Regards,
>
> Joe Astorino CCIE #24347 (R&S)
> Sr. Technical Instructor - IPexpert
> Mailto: jastorino_at_ipexpert.com
> Telephone: +1.810.326.1444
> Live Assistance, Please visit: www.ipexpert.com/chat
> eFax: +1.810.454.0130
>
> IPexpert is a premier provider of Classroom and Self-Study Cisco CCNA (R&S,
> Voice & Security), CCNP, CCVP, CCSP and CCIE (R&S, Voice, Security & Service
> Provider) Certification Training with locations throughout the United
> States, Europe and Australia. Be sure to check out our online communities at
> www.ipexpert.com/communities and our public website at www.ipexpert.com
>
>
>

-- 
Regards
Roy
Blogs and organic groups at http://www.ccie.net