2 upstreams 1 downstream BGP configuration optimization

[Kevin B]

Thank you Job and Toke.

I have tried the approach of marking import routes as large bgp 
communities, can you please tell me whether it's normal that bird is 
still trying to export numerous routes to my upstreams?

I did 'birdc restart [proto]' of both upstreams and this is what I get 
in 'rejected' columns:

UPSTREAM1:

   Routes:         774396 imported, 6 exported, 774396 preferred
   Route change stats:     received   rejected   filtered ignored   accepted
     Import updates:         777192          0          0 0     777192
     Import withdraws:          253          0        --- 0        253
     Export updates:        2320122    1551565     768545 ---         12
     Export withdraws:          259        ---        --- ---     783957

UPSTREAM2:

   Routes:         758555 imported, 6 exported, 9573 preferred
   Route change stats:     received   rejected   filtered ignored   accepted
     Import updates:        1039201          0          0 4    1039197
     Import withdraws:        48501          0        --- 22      48479
     Export updates:        4140531     808064    3332455 ---         12
     Export withdraws:        41861        ---        --- ---    1567606

DOWNSTREAM1:

   Route change stats:     received   rejected   filtered ignored   accepted
     Import updates:             22          0          0 1         21
     Import withdraws:       783868          0        --- 783864          4
     Export updates:       10916109         28          0 ---   10916081
     Export withdraws:       710987        ---        --- ---     710999

On 6/4/19 3:14 PM, Job Snijders wrote:
> Dear Kevin,
>
> On Tue, Jun 04, 2019 at 03:00:53PM +0000, Kevin B wrote:
>> I have 2 upstream transit providers and 1 downstream customer we provide
>> transit to - http://paste.debian.net/1086030/ (full Bird configuration with
>> explanation)
>>
>> There is a problem: Bird is exporting all the imported prefixes from
>> my upstreams back to them. For example 10.40.40.0/24 is being exported
>> from us even when AS20's customer doesn't announce it, because it is
>> announced somewhere else in the full table and we just export it back
>> from the full view.
>>
>> Here is `birdc show protocols all` output - http://paste.debian.net/1086033/
>>
>> I would like to prevent exporting the full view tables imported from
>> my upstreams back to them, can you help me to understand what is wrong
>> with the configuration and why does it happen?
> You'll have to mark the routes you receive on 'import', and act on those
> markers on 'export'.
>
> I've spoken a bit about how to make robust routing policies, I hope this
> is of use to you:
>
>      https://ripe77.ripe.net/archive/video/Job_Snijders-B._BGP_Policy_Update-20181017-140440.mp4
>
>      https://ripe77.ripe.net/presentations/59-RIPE77_Snijders_Routing_Policy_Architecture.pdf
>
> Specifically in your example, I've added the use of BGP Large
> Communities to help arrange what announcements go where, please compare
> this untested example with your own deployment: http://paste.debian.net/1086041/
>
> Kind regards,
>
> Job