[ixpmanager] Filtering a specific AS from a selection of ASes

[Nishal Goburdhan]

On 12 Jun 2018, at 15:23, Diarmuid O Briain wrote:

> Hi,
>
> I was wondering with IXP Manager what is the best way to filtering a
> specific AS from a selection of ASes. i.e. the selection of ASes are 
> not
> paying for a service that the specific AS provides at the IXP.

if this is a relationship between two peers at the IXP, then the IXP 
operator should not be interfering (read: this is not your business).

what you *should* do is to provide a standardised way for *any* peer, to 
elect not to send prefixes to another.  broadly speaking, this is done 
using a set of BGP communities that peers may elect to tag onto their 
route announcements.

that’s not something that’s specific to IXP manager though;  
assuming you’re using BIRD, there are examples on the BIRD site.  many 
IXPs also publish their bgp-community filtering policies.

btw, if you do not support filtering by community, and are just starting 
to look at it, consider that you probably want to start by supporting 
32bit ASNs  (ie.  ASNs larger than 65535).  you’ll need BIRD 1.6.3 or 
1.6.4, iirc.

—n.