Splitting ARIN assignment

Hyunseog Ryu r.hyunseog at ieee.org
Thu May 22 13:41:47 CDT 2008


What if upstream connection - Internet - goes down?
If you have fully redundant system implemented from both locations, so
you don't need another site for operation,
that will be fine.
But in normal situation, there is some dependency.
Also, if you have massive backup and/or data transaction between two
location,
it may good to have inter-connection - private link - between both location.

Origin AS loop can be resolved by BGP configuration feature, or putting
default route back to upstream connection. So probably that's not an
issue at all.

Real issue will be data/operation dependency between two locations such
as DNS server IP address and things like that.

If you are 100% sure about that there is no dependency between two
locations, you may omit the requirement for inter-connection between two
locations.

Hyun



Yamasaki, Charles wrote:
>> Make sure that your two location is inter-connected directly,
>>     
>
> Why is this required?  If you put static routes to point the remote /21 to
> the upstream provider on each side wouldn't that take care of the origin AS
> loop?
>
>
>
> On 5/22/08 10:45 AM, "Hyunseog Ryu" <r.hyunseog at ieee.org> wrote:
>
>   
>> I I were you, I will advertise as following.
>>
>> /21 Original ARIN allocation
>> /22 First half of ARIN allocation
>> /22 second half of ARIN allocation
>>
>> In this case, you will have backup /21 route just in case of filtering
>> or something like that.
>> But in normal case, traffic will be routed based on more specific
>> routes, which are /22s.
>>
>> In some case, upstream ISPs may filter based on strict filtering, which
>> means all BGP prefix announcement should be matched with registered CIDR
>> info including subnet size.
>> In most case, upstream ISP will accept any subnet size between
>> registered size (/21) and /24 size.
>>
>> Because of load sharing and traffic engineering requirement, it is easy
>> to handle those situation with /22 size.
>>
>> Make sure that your two location is inter-connected directly, and have
>> enough capacity when each of location upstream connection goes down.
>>
>>
>> Hyun
>>
>>
>> ames Kelty wrote:
>>     
>>> Hey all,
>>>
>>> I'm looking for an opinion from the group. I have an ARIN /21
>>> assignment and a new requirement for a second data center. Rather than
>>> ask for another assignment, I would like to advertise one /22 from one
>>> location and the other /22 from the second location both with the same
>>> asn. My apps will work that way, so I don't have an issue internally,
>>> but I'm looking for a broader base opinion on that.
>>>
>>> Thanks a lot!
>>>
>>> -James
>>>
>>>
>>>
>>>
>>>       
>>     
>
> Charles Yamasaki
> Manager Network Engineering
> Move Inc.
> 30700 Russell Ranch Rd
> Westlake Village, CA 91362
> O:   805.557.3829
> M:  805.603.6492
> F:   805.557.3870
>
>
>
>
>   





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