Wrong BGP NH metric

[Maria Matějka]

Fine then! I was suspicious about some changes in thread-next (where this problem can be actually reproduced with a good probability) and now I know that I should assess the whole algorithm instead.

Thanks a lot!
Maria

On October 7, 2022 11:29:09 AM UTC, Mihai <mihaigabriel at gmail.com> wrote:
>Hi Maria,
>
>Yes you are correct, the metric is not a random value but an old value, probably the first one after OSPF established.
>It looks like any subsequent change in the OSPF topology/metrics is not reflected in the BGP_NH metric.
>
>Best regards,
>Mihai
>
>On 03/10/2022 12:43, Maria Matejka via Bird-users wrote:
>> Hello!
>> 
>> I'd suspect the internal nexthop resolving mechanisms of missing the OSPF route update. When working on the multithreaded version, I came across a similar kind of bug and I honestly don't know yet how exactly this may be broken.
>> 
>> That said, is it possible that the metric is just an obsolete value from some previous route version?
>> 
>> Thanks for your report.
>> 
>> Maria
>> 
>> On 9/30/22 17:10, Mihai via Bird-users wrote:
>>> Hello,
>>> 
>>> The same issue on another RR, the BGP_Metric=60380 while the OSPF_Metric=60315.
>>> 
>>> bird> sh route 10:10 202.81.16.0/24 all
>>> Table vpntab4:
>>> 10:10 202.81.16.0/24 unicast [ROUTER2 2022-09-29 15:21:18 from 10.100.186.6] * (100/60380) [AS4826i]
>>>          Type: BGP univ
>>>          BGP.origin: IGP
>>>          BGP.as_path: 4826
>>>          BGP.next_hop: 10.100.186.6
>>> 
>>> bird> show route 10.100.186.6/32
>>> Table master4:
>>> 10.100.186.6/32      unicast [OSPF 2022-09-30 15:01:51] IA (150/60315) [10.100.186.4]
>>> 
>>> 
>>> 
>>> On 30/09/2022 09:08, Mihai wrote:
>>>> Hello,
>>>> 
>>>> First I would like to thank you for this amazing software!
>>>> 
>>>> I am running Bird 2.0.7 as RR for L3VPNs and on one RR the OSPF metric for the BGP NH is different than what's seen in BGP as shown below.
>>>> 
>>>> BGP PREF/METRIC = (100/61580) , OSPF_METRIC = 61480.
>>>> 
>>>> 
>>>> bird> sh route 10:10 94.207.96.0/19 all primary
>>>> Table vpntab4:
>>>> 10:10 94.207.96.0/19 unicast [ROUTER1 2022-09-28 00:10:09 from 10.100.186.1] * (100/61580) [AS15802i]
>>>>          Type: BGP univ
>>>>          BGP.origin: IGP
>>>>          BGP.as_path: 15802
>>>>          BGP.next_hop: 10.100.184.8
>>>> 
>>>> bird> sh route 10.100.184.8/32
>>>> Table master4:
>>>> 10.100.184.8/32      unicast [OSPF 2022-09-29 12:33:35] IA (150/61480) [10.100.186.5]
>>>> 
>>>> After restarting the BIRD OSPF adjancency the BGP metric changed to 61480.
>>>> 
>>>> 
>>>> Any help in understanding the issue would be much appreciated.
>>>> 
>>>> Thank you!
>>> 
>>> 
>

-- 
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