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RE: bgp4 info [7:94711] posted 11/17/2004
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If you don't have more than one provider, you will not need an ASN, and
unless you have a really huge company it's probably unnecessary to ask for
addressing from ARIN. In fact, if you only have a single provider you don't
really need BGP. The provider should be able to take care of this without
BGP into your network, especially since you're using addresses assigned by
that provider. 


>>> Jarmoc, Jeff 11/17/04 12:30:34 PM >>>
I'm going to tag onto this thread with a somewhat related question.

When using BGP to provide failover for two locations (each with a /24),
served by the same provider, is it necessary to apply for an ASN and/or
an IP address block from ARIN?

These two locations are reachable via a private network, and traffic
will be routed from one to the other over this private network in the
event one of the internet connections should fail.

-----Original Message-----
From: nobody@xxxxxxxxxxxxxx [mailto:nobody@xxxxxxxxxxxxxx] On Behalf Of
Sent: Wednesday, November 17, 2004 12:17 PM
To: cisco@xxxxxxxxxxxxxx 
Subject: RE: bgp4 info [7:94711]

If you're just announcing a /25 or /26 address space that was assigned
to you by your provider (out of your provider's address space), out of
one link, you're really not accomplishing anything by using BGP, as
they're probably already announcing the aggregate prefix from which your
addresses came from.

(not to mention that you'd be filtered and/or be adding more unneeded
routes into the global routing tables)=

If you're multihomed, then you need to get your ASN and run BGP.  You
usually get a /24 from one of your two providers and announce this
prefix out of both of your lines, though there has been a recent
discussion on nanog about arin providing provider-independant /24
address space to multihomed customers.

-----Original Message-----
From: Marc Barthoulot [mailto:barthom@xxxxxxxxxxx] 
Sent: Tuesday, November 16, 2004 9:41 PM
To: cisco@xxxxxxxxxxxxxx 
Subject: bgp4 info [7:94711]

I have planned to mount a bgp session between my internet access router
and the ISP's router.
I would like to have some opinion/experience.
I was wondering if I could announce to the IPS a subnet smaller than /24
routable IP addresses.
Would a /26 or /25 be suitable? I have heard that some provider may
filter subnet smaller than /24.

does anybody have experience in that field?

thank you very much,


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