[AusNOG] Peering on Seperate ASN

[Nathanael Bettridge]

I've seen similar things implemented for legacy/transitional reasons or where the customer terminated transit using real a real ASN and an AGVC using a Private ASN on the same kit. 

There's no technical reason it wouldn't work (depending on your kit). It's not that big a deal as long as you handle your configuration (eg, filters and BGP instances/peerings etc) properly. Not sure it would scale terribly well though.

Might need to prepend one of the ASes to advertisements of the other AS though to ensure all your paths for given IPs "end" in the same AS (in case anyone's doing anything funky around that case)

I have to say I agree with Mark & Mark though - think carefully if there's a better way before implementing.

Nathanael Bettridge
Prodigy Communications Pty Ltd
Mobile: +61 (0)4 1048 0170
Office: +61 (0)2 8214 8920
Fax:    +61 (0)2 9427 4203
Email:  nathanael at prodigy.com.au
Web:    www.prodigy.com.au 

> -----Original Message-----
> From: AusNOG [mailto:ausnog-bounces at lists.ausnog.net] On Behalf Of
> Mark ZZZ Smith
> Sent: Monday, 09 March 2015 19:50
> To: Mark Newton; daniel at glovine.com.au
> Cc: ausnog at lists.ausnog.net
> Subject: Re: [AusNOG] Peering on Seperate ASN
> 
> 
> 
> 
> 
> ________________________________
> From: Mark Newton <newton at atdot.dotat.org>
> To: daniel at glovine.com.au
> Cc: ausnog at lists.ausnog.net
> Sent: Monday, 9 March 2015, 18:14
> Subject: Re: [AusNOG] Peering on Seperate ASN
> 
> 
> 
> On 6 Mar 2015, at 5:55 pm, daniel at glovine.com.au wrote:
> 
> He was interested to know if he can peer with a separate ASN to what he
> uses for transit,  AKA
> >
> >Transit ASN 1001
> >Peering ASN 1002
> >And then setting up BGP between the 2
> >Would this work correctly using internal IP’s between the 2 BGP sides?
> >By my knowledge I believe this could work, But want to make sure
> 
> 
> It isn’t a question of whether it could work, it’s a question of what possible
> reason you’d have to do it that way.
> 
> / I'm also curious to know why. I can only think of reasons why it would just
> make things harder without any benefit. If it is motivated by classifying
> routes into transit and peering received, that is what BGP communities are
> for.
> 
> Why not transit and peering on the same ASN, just like virtually every other
> network operator on the planet?  What is driving your customer to invent a
> unique deployment with side-effects they (and you) aren’t equipped to
> debug, when there are tens of thousands of networks out there doing
> exactly the same thing in a standard, well-understood way?
> 
> Sounds like complexity for complexity’s sake.
> 
>   - mark
> 
> 
> 
> 
> 
> 
> _______________________________________________
> AusNOG mailing list
> AusNOG at lists.ausnog.net
> http://lists.ausnog.net/mailman/listinfo/ausnog
> _______________________________________________
> AusNOG mailing list
> AusNOG at lists.ausnog.net
> http://lists.ausnog.net/mailman/listinfo/ausnog