BGP Peering shuts down with "add paths tx;"

[Tim Weippert]

Hi All,

i try to activate "add paths tx;" from my Bird2 (2.0.12) Routeserver to a Cisco IOS-XR Systems (7.9.2), after i add
the config on Bird side, the IOS-XR shuts down the peering:

%ROUTING-BGP-3-MALFORM_UPDATE : Malformed UPDATE message received from neighbor <IPV6-RR> (VRF: INTERNET) - message length 160 bytes, error flags 0x00000008, action taken "Reset". Error details: "Error 0x00000008, Field "MP_REACH-NLRI", Attribute 14 (Flags 0x00, Length 0), Data [6d]". NLRIs: [IPv4 Unicast]
%ROUTING-BGP-5-ADJCHANGE : neighbor <IPV6-RR> Down - BGP Notification sent, illegal network (VRF: INTERNET) (AS: 65000)
%ROUTING-BGP-3-MALFORM_UPDATE : Malformed UPDATE message received from neighbor <IPV6-RR> (VRF: INTERNET) - message length 160 bytes, error flags 0x00000008, action taken "Reset". Error details: "Error 0x00000008, Field "MP_REACH-NLRI", Attribute 14 (Flags 0x00, Length 0), Data [6d]". NLRIs: [IPv4 Unicast]
%ROUTING-BGP-5-NBR_NSR_DISABLED_STANDBY : NSR disabled on neighbor <IPV6-RR> on standby RP due to BGP Notification sent (VRF: INTERNET)
%ROUTING-BGP-5-ADJCHANGE : neighbor <IPV4-RR> Down - BGP Notification sent, illegal network (VRF: INTERNET) (AS: 65000)

I found some hints on the following bug id from cisco:

https://bst.cisco.com/quickview/bug/CSCvy23472

There it states:

---
Under add-path send/receive enable scenario, when IOS-XR BGP received update message whose path-id is missed in NLRI, BGP think this message to be malformed and reset this BGP session. This behavior is expected behavior.
---

Does this means, that bird doesn't add the path-id as expected?
Is there some known caveouts around?

Same configuration on BGP Peerings to Cisco IOS-XE are working fine and accept the additional paths.

Thanks,
tim

-- 
Tim Weippert
http://weiti.org - weiti at weiti.org
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