[c-nsp] Multihoming

[Heath Jones]

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                |
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