[c-nsp] Multihoming

Joseph Jackson recourse at gmail.com
Wed Sep 15 12:06:59 EDT 2010


I currently do this for one of my sites and haven't had any issues.
You just get a LOA from the ISP you get your /24 from and send it to
the other ISP.  Easy Peasy.



On Wed, Sep 15, 2010 at 10:30 AM, Heath Jones <hj1980 at gmail.com> wrote:
> Jon there seems to be a bit of a common belief that advertising a /24 or
> some prefix that has been assigned by a provider, out to another provider,
> is bad practise. I don't get it either and haven't seen issues myself.
>
> The only scenario I can think of is (in some odd configurations) when the
> original provider sees part of their own network being advertised by another
> ISP, they filter it and it breaks connectivity, or the original provider's
> igp contains that prefix somehow already.. ?
>
>
>
>
>
>
> On 15 September 2010 16:17, Jon Lewis <jlewis at lewis.org> wrote:
>
>> On Wed, 15 Sep 2010, Voigt, Thomas wrote:
>>
>> Hi Rocker,
>>>
>>> Rocker Feller wrote:
>>>
>>> I am pretty new to this concept and would appreciate any
>>>> guidance on how as
>>>> a customer I can achieve redundacy with autofailover between 2 ISPs.
>>>>
>>>
>>> You need PI space to do this. Because each ISP can only route his own PA
>>> spaces plus the PI spaces from his customers.
>>>
>>
>> You don't need PI space to multihome.  At least not in the ARIN region. You
>> do generally need at least a /24 if you want any reasonable chance of "the
>> internet" accepting your BGP announcement.
>>
>>
>> ----------------------------------------------------------------------
>>  Jon Lewis, MCP :)           |  I route
>>  Senior Network Engineer     |  therefore you are
>>  Atlantic Net                |
>> _________ http://www.lewis.org/~jlewis/pgp for PGP public key_________
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