Support for dual AS and AS migration
Does BIRD have any support for AS migration mechanism as mentioned in RFC7705 https://tools.ietf.org/html/rfc7705? Something like https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_bgp/configuration/... I know it can be achieved by functions, but maybe there is already simplier way to get this done. Best regards, Adam Król
On dim. 18 févr. 13:25:37 2018, Adam Król wrote:
Does BIRD have any support for AS migration mechanism as mentioned in RFC7705 https://tools.ietf.org/html/rfc7705? Something like https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_bgp/configuration/...
I know it can be achieved by functions, but maybe there is already simplier way to get this done.
Hi, You can choose the local AS on each BGP protocol instance, is it sufficient? -- alarig
Is there any description how does AS path look like in that kind of configuration? Let's consider that scheme: PEER A <-> ISP (bird - one instance) <-> PEER B AS 65499 <-> AS 65505 AS 65510 <-> AS 65496 How side A see side B? Bird adds all AS numbers of ISP to AS path? Best regards, Adam Król -----Original Message----- From: Bird-users [mailto:bird-users-bounces@network.cz] On Behalf Of Marco d'Itri Sent: Sunday, February 18, 2018 5:23 PM Cc: bird-users@network.cz Subject: Re: Support for dual AS and AS migration On Feb 18, Alarig Le Lay <alarig@swordarmor.fr> wrote:
You can choose the local AS on each BGP protocol instance, is it sufficient? No, because this still required coordinating the exact time of the AS change with each neighbor.
-- ciao, Marco
On Sun, Feb 18, 2018 at 05:00:36PM +0000, Adam Król wrote:
Is there any description how does AS path look like in that kind of configuration?
Let's consider that scheme:
PEER A <-> ISP (bird - one instance) <-> PEER B AS 65499 <-> AS 65505 AS 65510 <-> AS 65496
How side A see side B? Bird adds all AS numbers of ISP to AS path?
Hi When route is exported to a BGP peer, BIRD prepends ASN based on ASN of exporting BGP protocol instance. Therefore, only one ASN is prepended to AS path automatically. If you want to have both AS numbers in AS path, you would have to use filters. -- 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."
On Feb 18, Ondrej Zajicek <santiago@crfreenet.org> wrote:
When route is exported to a BGP peer, BIRD prepends ASN based on ASN of exporting BGP protocol instance. Therefore, only one ASN is prepended to AS path automatically. If you want to have both AS numbers in AS path, you would have to use filters. This is not about prepending, but about being able to negotiate the session using either of two different ASNs.
-- ciao, Marco
Somewhat related to this, I wrote this patchset last year: http://trubka.network.cz/pipermail/bird-users/2017-March/thread.html#11084 The idea was to let you configure two AS numbers that a remote peer can connect to us with, so that the remote peer can be reconfigured to use a different AS number without the local machine needing to reconfigured at the same time. (The converse case, where the local machine will reconnect with a secondary AS number if connecting with the primary AS number fails is more involved, and in my use case, I control both endpoints anyway, so this was sufficient.) If there's interest in this patchset I can dust it off and try resubmitting it. On Sun, Feb 18, 2018 at 01:25:37PM +0000, Adam Król wrote:
Does BIRD have any support for AS migration mechanism as mentioned in RFC7705 https://tools.ietf.org/html/rfc7705? Something like https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_bgp/configuration/...
I know it can be achieved by functions, but maybe there is already simplier way to get this done.
Best regards, Adam Król
* Lennert Buytenhek <buytenh@wantstofly.org>
Somewhat related to this, I wrote this patchset last year:
http://trubka.network.cz/pipermail/bird-users/2017-March/thread.html#11084
The idea was to let you configure two AS numbers that a remote peer can connect to us with, so that the remote peer can be reconfigured to use a different AS number without the local machine needing to reconfigured at the same time.
(The converse case, where the local machine will reconnect with a secondary AS number if connecting with the primary AS number fails is more involved, and in my use case, I control both endpoints anyway, so this was sufficient.)
If there's interest in this patchset I can dust it off and try resubmitting it.
Hi Lennert, In case you do decide to work on this again, I'd suggest you take a look at the FRR / Cumulus feature where you can configure a peer/peer-groups ASN to be the string «external». This means to accept the peer to be in any arbitrary ASN (except for the local one). I've found this to be a very convenient feature, and it'd be nice to see it in BIRD too. https://docs.cumulusnetworks.com/display/DOCS/Border+Gateway+Protocol+-+BGP#... Tore
On Mon, Mar 05, 2018 at 07:22:22AM +0100, Tore Anderson wrote:
* Lennert Buytenhek <buytenh@wantstofly.org>
Somewhat related to this, I wrote this patchset last year:
http://trubka.network.cz/pipermail/bird-users/2017-March/thread.html#11084
The idea was to let you configure two AS numbers that a remote peer can connect to us with, so that the remote peer can be reconfigured to use a different AS number without the local machine needing to reconfigured at the same time.
If there's interest in this patchset I can dust it off and try resubmitting it.
Hi Lennert,
In case you do decide to work on this again, I'd suggest you take a look at the FRR / Cumulus feature where you can configure a peer/peer-groups ASN to be the string «external». This means to accept the peer to be in any arbitrary ASN (except for the local one).
I've found this to be a very convenient feature, and it'd be nice to see it in BIRD too.
Hi The original patchset allowed accepting both internal and external BGP sessions on one BGP instance, which makes it more complicated that just accepting multiple AS numbers. Esp. with BIRD 2.0.1, which supports also BGP confederations and therefore has three discinct kinds of BGP sessions. I think that reasonable interface would be to allow to specify the number set (of allowed AS numbers), like is used in filters, but still keep it limited to one kind (internal, external, inter-confederation) of BGP sessions. Such feature we would accept or perhaps i will implement it someday. -- 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."
participants (6)
-
Adam Król -
Alarig Le Lay -
Lennert Buytenhek -
md＠Linux.IT -
Ondrej Zajicek -
Tore Anderson