[FROG] ibgp regression on 8.5.2 ?

[Donatas Abraitis]

Unfortunately, this is horrible, but no. iBGP peers exchange AIGP
attributes. Workaround would be to switch to using eBGP sessions
temporarily if possible.

On Fri, Jun 30, 2023 at 3:27 PM mike tancsa <mike at sentex.net> wrote:

> Hi,
>
>     Thanks for the explanation.  Is there any way to work around this via
> configuration ? e.g. temporarily ignore the setting as Transitive ? This
> makes for upgrading very intrusive as I have to upgrade all the ibgp
> routers at once which is very service effecting.
>
>     ---Mike
> On 6/30/2023 3:20 AM, Donatas Abraitis wrote:
>
> Hello, Mike!
>
> With the 8.5.0 release, the new BGP attribute AIGP (Accumulated IGP Metric
> Attribute) was introduced. This new attribute was mistakenly set as
> Transitive. This was fixed (53afb27
> <https://github.com/FRRouting/frr/commit/53afb27eb892a107c9426a01dbba82bee6fa86a7>)
> with the 8.5.2 release, but it's not backward-compatible between 8.5.x
> versions. We suggest using only the latest version of the 8.5 release.
>
> If you see such errors/notifications, upgrade to the latest 8.5.x
> versions, and avoid using 8.5.0, and 8.5.1.
>
> AIGP attribute must be flagged as "Transitive"
>
> %NOTIFICATION: received from neighbor X.Y.Z.W 3/4 (UPDATE Message Error/Attribute
> Flags Error) 14 bytes 80 1a 0b 01 00 0b 00 00 00 00 00 00 00 01
>
> (This affects only iBGP sessions).
>
> On Fri, Jun 30, 2023 at 12:09 AM mike tancsa <mike at sentex.net> wrote:
>
>> Hi, I am guessing it is this commit ?
>>
>> commit 231e4de73f46b9c75a07bf0144aafce18aeb3a55
>> Author: Donatas Abraitis <donatas at opensourcerouting.org>
>> Date:   Mon May 8 22:49:10 2023 +0300
>>
>>      bgpd: Make sure AIGP attribute is non-transitive
>>
>>      The AIGP attribute is an optional, non-transitive BGP path attribute.
>>
>>      Signed-off-by: Donatas Abraitis <donatas at opensourcerouting.org>
>>
>>
>> Is there a way to work around this in configs ?
>>
>>      ---Mike
>>
>> On 6/29/2023 2:39 PM, mike tancsa wrote:
>> > I was updating an internal distribution router that got wedged in
>> > vtysh from 8.5 to 8.5.2 and found all my ibgp peers would not come up.
>> > Same error on the half dozen peers
>> >
>> > Jun 29 14:00:55 ibgp-4 bgpd[38150]: [HZN6M-XRM1G] %NOTIFICATION:
>> > received from neighbor xx.yy.zz.251 3/4 (UPDATE Message
>> > Error/Attribute Flags Error) 14 bytes 80 1a 0b 01 00 0b 00 00 00 00 00
>> > 00 00 01
>> > Jun 29 14:01:00 ibgp-4 bgpd[38150]: [HZN6M-XRM1G] %NOTIFICATION:
>> > received from neighbor xx.yy.zz.251 3/4 (UPDATE Message
>> > Error/Attribute Flags Error) 14 bytes 80 1a 0b 01 00 0b 00 00 00 00 00
>> > 00 00 01
>> > Jun 29 14:01:05 ibgp-4 bgpd[38150]: [HZN6M-XRM1G] %NOTIFICATION: sent
>> > to neighbor xx.yy.zz.251 3/4 (UPDATE Message Error/Attribute Flags
>> > Error) 14 bytes c0 1a 0b 01 0
>> >
>> > On the older versions of frr,
>> >
>> > [NYD0B-A3BTB][EC 33554433] AIGP attribute must be flagged as
>> "Transitive"
>> > [HZN6M-XRM1G] %NOTIFICATION: sent to neighbor xx.yy.zz.241 3/4 (UPDATE
>> > Message Error/Attribute Flags Error) 14 bytes 80 1a 0b 01 0
>> > [GW152-RVASS][EC 33554455] bgp_process_packet: BGP UPDATE receipt
>> > failed for peer: xx.yy.zz.241
>> >
>> > I downgraded from 8.5.2 to 8.5.1 and all was good. Also, another peer
>> > thats still running 7.x was fine with it all.
>> >
>> >
>> > Nothing special about the config. One of the untouched boxes running 8.5
>> >
>> >  neighbor THOTLAN peer-group
>> >  neighbor THOTLAN remote-as 11647
>> >  neighbor THOTLAN description Core1LanEx
>> >  neighbor THOTLAN update-source [dot.251]
>> >  neighbor .241 peer-group HOTLAN
>> >  neighbor .241 description The box the flipped out
>> >  neighbor .241 bfd
>> >   neighbor THOTLAN activate
>> >   neighbor THOTLAN next-hop-self
>> >   neighbor THOTLAN weight 111
>> >
>> > The box I tried to upgrade from 8.5 to 8.5.2 that then went back to
>> 8.5.1
>> >
>> >  neighbor THOTLAN peer-group
>> >  neighbor THOTLAN remote-as 11647
>> >  neighbor THOTLAN update-source [dot.241]
>> >  neighbor THOTLAN timers 16 50
>> >  neighbor .251 description One of the many other peers that didnt like
>> me
>> >  neighbor .251 bfd
>> >   neighbor THOTLAN activate
>> >   neighbor THOTLAN next-hop-self
>> >   neighbor THOTLAN soft-reconfiguration inbound
>> >   neighbor THOTLAN weight 109
>> >
>> >
>> >     ---Mike
>> >
>> >
>>
>
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