From: Hyunseog Ryu (r.hyunseog@ieee.org)
Date: Thu Aug 02 2007 - 20:02:50 ART
I think unique routing policy is the idea why running BGP protocol.
Without unique routing protocol, why do you want to run BGP routing
protocol?
That's why every Friday I get BGP routing summary with in-consistent AS
Origin report.
And this will make hard to track whether BGP prefix in question is
hijacked one or legitimate one.
For your another comment, I don't have a problem to have public ASN and
public IP prefix for BGP announcement if he/she has legitimate reason
for it.
I know some guys have multiple OC3c to basement for running servers and
things like that.
It can be research thing, or personal entertainment thing... :-)
I know Scott Morris has toys in his basement, too. ^.^
Hyun
sheherezada@gmail.com wrote:
> Not really necessary. You can use a private ASN even when multihoming
> with two different providers and even if announcing some [provider
> independent] prefixes. They will just strip your private ASN when
> announcing your prefixes to the outside world.
>
> You need your public AS number only if you want to express a
> particular routing policy, i.e. you do have a particular preference as
> to which of the upstream providers should be used for incoming
> traffic. Otherwise, there is absolutely no problem for the outside
> world to see that the prefix appears to be originated from different
> ASs.
>
> Mihai Dumitru
> CCIE #16616
>
> P.S. And I know a person who had a public ASN and PI address space for
> his own personal use - it's not me :)
>
>
> On 7/29/07, Hyunseog Ryu <r.hyunseog@ieee.org> wrote:
>
>> Upstream providers will remove private AS number when they readvertise
>> to other ISPs.
>> So natually if you have multi-homed to multiple ISPs, the route will be
>> appeared as inconsistent ORIGIN AS, which will not appeared as valid
>> route from RFC viewpoint.
>> According to RFC - I don't remember which -, it should be originated
>> from single AS number.
>> Also, customer who uses Private ASN with multiple upstream providers can
>> NOT implement consistent routing policy for that matter.
>> So multihomed customer with private ASN is not recommended for multiple
>> providers upstream connection.
>> If customer have multiple connections with SAME providers, they may use
>> private ASN for load sharing purpose.
>>
>> Hyun
>>
>>
>> Gregory Gombas wrote:
>>
>>> What are you losing by using a private ASN? You can still advertise
>>> your own dedicated IP address space via both providers can't you? Your
>>> ISP's simply needs to remove that private AS when passing the update
>>> to other ISP's...
>>>
>>> Am I missing something here?
>>>
>>> On 7/29/07, Herbert Maosa <asawilunda@googlemail.com> wrote:
>>>
>>>
>>>> If you dont have your own ASN, you will most likely have to use a private
>>>> ASN to connect to the two ISPs. Remember that if you use the ISPs ASN then
>>>> you are an extension of that ISP. Using the private ASN in this case will
>>>> permit you to be totally provider independent.
>>>>
>>>> regards,
>>>>
>>>> Herbert.
>>>>
>>>>
>>>> On 7/29/07, Gregory Gombas <ggombas@gmail.com> wrote:
>>>>
>>>>
>>>>> When connecting to the internet via two different ISP's, why is it
>>>>> necessary to have a unique AS?
>>>>>
>>>>> What if you simply configured your BGP router with the same AS number
>>>>> as one of your ISP's?
>>>>>
>>>>> Considering there are only 64511 unique AS numbers, I assume that most
>>>>> if not all the AS numbers are already taken. What do companies do in
>>>>> the case they cannot get their own AS number and need to multihome?
>>>>>
>>>>> Thanks,
>>>>> Greg
>>>>>
>>>>>
>>>>>
>>>>>
>>>> _______________________________________________________________________
>>>>
>>>>
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>>>>>
>>>> --
>>>> Kindest regards,
>>>> hm
>>>>
>>>>
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