Good morning! OK, understood :-} I can say for sure that it's not a 'BGP protocol limitation' since I have exactly that setup running on our warehouse border router ( /31 ppp addressing on link to upstream bgp peer) and it has worked flawlessly since installation some time ago. But that one IS a RouterOSv6, so you could be seeing a v7 'idiosyncrasy' - if the issue persists, perhaps consider logging a support case with our help desk - they can run up a test to reproduce the problem and report to MT for comment. <rant> As a completely pedantic side rant, a lot of this talk about /31 network support is nothing more than an argument in semantics IMO. I'll probably open up a can of worms here, so if that happens, apologies for hijacking your thread :-} /31 is not really a 'subnet' anyway, in the sense that a subnet is really just a conceptual structure for a broadcast domain. More properly, I prefer to call /31 an 'address range' instead of 'subnet', as it is a way better description of what we are really working with and helps to dispel all those myths about how routerOS implements it poorly or partially or fudges it or whatever. It is what it is - a point to point addressing scheme. For "slash 31", it just so happens by fortune, coincidence or chance, that the addresses at each end of the ppp link happen to be adjacent and fit a /31 mask RANGE ; ) However <substitute your router platform name here> represents the addressing scheme in the admin/configuration interface is irrelevant, and whether it allows the user to actually enter an address in the form a.b.c/31 is unimportant - the underlying technical implementation will be the same. 😏 </rant> Cheers! Mike. -----Original Message----- From: Public <public-bounces@talk.mikrotik.com.au> On Behalf Of Christopher Hawker via Public Sent: Monday, 8 January 2024 6:55 PM To: MikroTik Australia Public List <public@talk.mikrotik.com.au> Cc: Christopher Hawker <chris@thesysadmin.au> Subject: Re: [MT-AU Public] /31 Deployments for Point-to-Point links Hey Mike, Apologies, what I meant was that if I use a /30 subnet for the handoff the config works, however with a /31 it does not. We've got about 80 sessions (bilats, route servers and transit links) so enabling debug logging floods my core with about 1000 entries per second. Looking at the other router with the single session gives me nothing referencing the new session. Regards, Christopher Hawker On Mon, 8 Jan 2024 at 18:30, Mike Everest via Public < public@talk.mikrotik.com.au> wrote:
G'day!
If the session doesn't establish, it won't have anything to do with the networks you are trying to advertise...
Do routerOS logs give you any clues? If not, try adding bgp debug to system logging :)
Cheers! Mike.
----Original Message----- From: Public <public-bounces@talk.mikrotik.com.au> On Behalf Of Christopher Hawker via Public Sent: Monday, 8 January 2024 5:33 PM To: public@talk.mikrotik.com.au Cc: Christopher Hawker <chris@thesysadmin.au> Subject: [MT-AU Public] /31 Deployments for Point-to-Point links
Hey all,
Trying to stand-up a BGP session between a CCR2004-1G-12S+2XS and a CCR2004-16G-2S+ using a /31 for the link. I'm able to ping across the CCR2004-16G-2S+ link no problem, however, the BGP session doesn't establish. I'm attempting to move an existing session from a /30 where it works in order to conserve IP space. Is there some skullduggery going on, or is 7.13 just not RFC3021-compliant?
Thanks, Christopher Hawker _______________________________________________ Public mailing list Public@talk.mikrotik.com.au http://talk.mikrotik.com.au/mailman/listinfo/public_talk.mikrotik.com. au
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