On Mon, Jan 22, 2018 at 2:00 PM, Piotr Marciniak <zboj@mnc.pl> wrote:
Dear Advisors ;],

Thank you for all posts. But still I do not know how to make Bird working with 4B communities and if I may do this - whether it will be accepted for our peers? In short - I do not know how to adapt to 4B communities following examples:

https://gitlab.labs.nic.cz/labs/bird/wikis/Route_server_with_community_based_filtering_and_multiple_RIBs
https://gitlab.labs.nic.cz/labs/bird/wikis/Route_server_with_community_based_filtering_and_single_RIB

Is there any way to enable 4B communities in bird.conf?

I do not have any problem with 4B ASn. I set bgp peering sessions from Bird with 4B ASn. Even our IX has AS205082.

This is why I put 2 questions:

1. Is it possible to enable 4B ASn for communities in Bird? Will it work
with other rouers?

This is not bird thing. You can not use 4B AS numbers with "old" communities.
http://bird.network.cz/?get_doc&v=16&f=bird-5.html#ss5.2
pair

This is a pair of two short integers. Each component can have values from 0 to 65535. Literals of this type are written as (1234,5678). The same syntax can also be used to construct a pair from two arbitrary integer expressions (for example (1+2,a)).

But there is newer version of communities called large communities:
lc

This is a specialized type used to represent BGP large community values. It is essentially a triplet of 32bit values, where the first value is reserved for the AS number of the issuer, while meaning of remaining parts is defined by the issuer. Literals of this type are written as (123, 456, 789), with any integer values. Similarly to pairs, LCs can be constructed using expressions for its parts, (e.g. (myas, 10+20, 3*10), where myas is an integer variable).

http://largebgpcommunities.net/

Those can be used with 4B AS numbers, but not every router supports them.
 
2. Can we use instead private ASn just for community filters? Are they
processed corretly by other Internet routers of our peers?

You can use whatever numbers you want. AS numbers are used there for clarity and interoperability. But it is rare needed to share communities between operators.
 

 Please - do not explain me theoretical difference between 16 and 32 bits. Question is simple - can I use 4B communities for filters? If not - what 16bit "fake ASn" I can use instead safely?

So if you know the difference between 16 and 32 bits, than why you surprised that you can not put 32-bit number into 16-bit entity? :)
 

Best wishes,

Piotr Marciniak


-----Oryginalna wiadomość----- From: Paweł Nastachowski
Sent: Monday, January 22, 2018 1:12 PM
To: Piotr Marciniak
Cc: bird-users@network.cz
Subject: Re: Community for small IX - problem with 4B ASN

Hi Piotr,

I should use extended community for 4B ASN, because normal community is too small “Encodes a 32-bit value displayed as “16-bit ASN:16-bit value”.

Regards,
Pawel

-----Wiadomość oryginalna-----
Od: Bird-users <bird-users-bounces@network.cz> w imieniu użytkownika Piotr Marciniak <zboj@mnc.pl>
Data: poniedziałek, 22 stycznia 2018 11:15
Do: "bird-users@network.cz" <bird-users@network.cz>
Temat: Community for small IX - problem with 4B ASN

   Hello,

   I've spent a while on below docs and faced a problem with 4B ASN we use.
   Bird reports an error 'when 'myas' is 4B => so above 65535.
   See some testing example below:

   bird> configure
   Reading configuration from /etc/bird/bird.conf
   /etc/bird/bird.conf, line 81: Value 165250 out of range (0-65535)

   The only way this config reports no error is to set here private ASn - fe.
   65250. But it will never match our real ASn.

   Two questions:

   1. Is it possible to enable 4B ASn for communities in Bird? Will it work
   with other rouers?
   2. Can we use instead private ASn just for community filters? Are they
   processed corretly by other Internet routers of our peers?

   Or maybe there is another work around?

   Best wishes,

   Peter


   -----Oryginalna wiadomość-----
   From: Piotr Marciniak
   Sent: Friday, December 29, 2017 5:01 PM
   To: Ondrej Zajicek
   Cc: bird-users@network.cz
   Subject: Re: Community for small IX


   There are some examples in BIRD wiki, mainly:

    https://urldefense.proofpoint.com/v2/url?u=https-3A__gitlab.labs.nic.cz_labs_bird_wikis_Route-5Fserver-5Fwith-5Fcommunity-5Fbased-5Ffiltering-5Fand-5Fmultiple-5FRIBs&d=DwIDaQ&c=gxW9PgscCAGwFImBgfkGkoANogu61GVPNv0sglxAtik&r=5Q01PsGCLGh5Iipn2_EFz2pKmXKRl5oJ_tHzyrwTUhrj4D27CXd9SGXgnGWoH5Yy&m=b6e1rT2mu_bWkZiOT-71FnOGwrXSx-xnpaRwbI3-BFI&s=2UgZOD_Fkqt6ZgVqlXm_vXRiY1LP_MTlkWo-TGVqAtE&e=
   https://urldefense.proofpoint.com/v2/url?u=https-3A__gitlab.labs.nic.cz_labs_bird_wikis_Route-5Fserver-5Fwith-5Fcommunity-5Fbased-5Ffiltering-5Fand-5Fsingle-5FRIB&d=DwIDaQ&c=gxW9PgscCAGwFImBgfkGkoANogu61GVPNv0sglxAtik&r=5Q01PsGCLGh5Iipn2_EFz2pKmXKRl5oJ_tHzyrwTUhrj4D27CXd9SGXgnGWoH5Yy&m=b6e1rT2mu_bWkZiOT-71FnOGwrXSx-xnpaRwbI3-BFI&s=KjVYea-iJRNl8BxFQFgkEeHLWFK8qwenAm_GRJDH4Q4&e=

   --
   Elen sila lumenn' omentielvo

   Ondrej 'Santiago' Zajicek (email: santiago@crfreenet.org)
   OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net)
   "To err is human -- to blame it on a computer is even more so."



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