Re: Unique Local Address (ULA) - IPv6

Cool, thanks again Joe, its v clear now :)

Typos are my forte :)

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

> 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
>>>>>>
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>>>>>>
>>>>>>
>>>>>> 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
>>>>>>
>>>>>>
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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 &
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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
>>>> 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
>
>
>

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