[ixpmanager] Setup BGP Community Filter

[Barry O'Donovan (INEX)]

Hi Deri,

> i want to setup extended community for our customer, maybe you can info 
> for the step or reference.

Just to avoid any terminology issues, IXP Manager / route servers in 
general do not support extended communities - just standard 32-bit 
communities and large communities. These days we'd favour large 
communities due to the prevalence of 32-bit ASNs.

To put some context on this question as you are providing very little 
detail, I'm going to assume the following:

You have member A with asn 65536 who wishes to use the route servers but 
not exchange routes with member B with asn 65511. They both peer with 
your route servers with asn 65500.

There are two principle ways to achieve this:


(1) The member A handles this themselves.
=============================================

This is the most appropriate way of implementing this - the member 
applies their own routing policy on their own router.

They would tag the routes advertised to the route servers with large 
community 65500:0:65511 (do not advertise to 65511). The standard 
community would be 0:65511.

They would also filter routes learned from the route server so as to 
ignore routes where the next hop asn is 65511.


If you are running >6.4.0 and have implemented the UI based community 
filtering (https://github.com/inex/IXP-Manager/releases/tag/v6.4.0) then 
the member can do this themselves in IXP Manager.


(2) You do it for the member.
=============================================

In this scenario, you are taking on some responsibility for implementing 
the member's routing policy.

Again, if you are running >6.4.0 and have implemented the UI based 
community filtering, you can do this in the UI for them.

If not, you'll need to implement it via customer import and export files 
which will be included in your route server configuration.

See and read: 
https://docs.ixpmanager.org/latest/features/route-servers/#per-asn-import-export-filters

Sample skinned files for this would be:

f_import_as65536.foil.php  [this is for routes learned from as65536 and 
you want to tag them for the member]:

     # Filter to stop adverts to AS65511
     bgp_large_community.add((65500,0,65511));


f_export_as65536.foil.php [this is for routes advertised to as65536 and 
you want to filter out routes form as65511]:

     if (bgp_path.first = 65511 ) then {
         reject;
     }



Hope that helps,
  - Barry




> On Sat, Oct 19, 2024 at 11:49 PM Barry O'Donovan (INEX) 
> <barry.odonovan at inex.ie <mailto:barry.odonovan at inex.ie>> wrote:
> 
> 
>     Hi Deri,
> 
>     Deri Yusep Apriyadi via ixpmanager wrote on 14/10/2024 11:36:
>      > I'm a little confused about where to start from activating the
>     Community
>      > Filter for Customers as in the following link
>      >
>     https://github.com/euro-ix/rs-workshop-july-2017/wiki/Route-Server-BGP-Community-usage,
> 
> 
>     I do not know what you mean by 'activating the Community Filter'?
> 
>     If you are using IXP Manager's route server configuration, you do not
>     need to do anything. Customers tag their routes, not the IX.
> 
>     If you provide more information on what you want to achieve, we can
>     probably help.
> 
>        - Barry
> 
> 


-- 

Kind regards,
Barry O'Donovan
INEX Operations

https://www.inex.ie/support/
+353 1 531 3339