Re: Unique Local Address (ULA) - IPv6

Bah, my God I can't type tonight!!! Apologies for the typos...

centrally assigned global-id is the FC00::/8
randomly generated global-id is the FD00::/8

As Scott said I'd watch the wording BUT ...still remember that the 40 bits
following FD you still don't get to choose. It is randomly generated by the
router. Now, the 16 bits after THAT is up to you no matter if you are using
centrally assigned (FC00::/8) or randomly generated (FD00::/8)

[FC][Global-ID][Subnet-ID][Interface ID]

FC: 8 bits
Global-ID: 40 bits assigned to you by a central place
Subnet-ID: 16 bits you get to play with
Interface-ID: 64 bits

[FD][Global-ID][Subnet-ID][Interface ID]

FD: 8 bits
Global-ID: 40 bits "pseudo-randomly" generated by the router based on things
like the time of day, your mac-address and such...
Subnet-ID: 16 bits you get to play with
Interface-ID: 64 bits

So really the only difference is the 40-bit global ID ... which basically
uniquely identifies your "SITE". You have randomly generated or centrally
assigned.

THAT should clear it up for good : )

On Wed, Dec 16, 2009 at 1:29 AM, Joe Astorino <jastorino_at_ipexpert.com>wrote:

> You are welcome,
>
> Keep in mind IPv6 "site-local" and "unique-local" addressing is something
> that seems to have been revised and changed quite a bit. First we had
> site-local which like I said is now depricated officially, but still seen in
> a lot of Cisco documentation. Essentially people in the IETF could not
> agree on what defined a "site."
>
> With Unique-Local it seems that nobody is quite sure yet what to do or how
> to implement the whole centrally assigned thing (FD00::/8). I'd keep an eye
> on it if you are interested, but for the lab I'd do what they tell you.
> When in doubt, I'd ask the proctor, and if still you are in trouble, I'd go
> with the FD00::/8 range and just let the router randomly generate your
> global ID.
>
> On Wed, Dec 16, 2009 at 1:18 AM, Roy Waterman <roy.waterman_at_gmail.com>wrote:
>
>> 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:
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>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> 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
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>>>> 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
>>
>
>
>
> --
> 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
Blogs and organic groups at http://www.ccie.net