BGP warning in log, how to diagnose

[EtherNation_Use]

Create Date: Mar 1 2012 7:36AM

Hi,

I'm getting the below error on a Summit X480 running ExtremeXOS 15.1.1.6.

This warning log entry has been showing up since I updated from 12.6.2.10 to 15.1.1.6.

03/01/2012 16:16:12.70 A route can not be advertised because its next hop is the same as the
address of the peer to which it was being sent.
VR: 0x00000002
Neighbor index: 3
Next Hop Address: x.x.x.33


x.x.x.33 is the upstream provider who the summit is connected to. I have configured a route-policy to filter out anything but one /24 subnet.

When I run:

show bgp neighbor x.x.x.33 transmitted-routes all

only the correct route shows, and no rotues shows as "rejected" or "suppressed".



Can anybody help me how to diagnose and correct this? if its just not a bug.

Any help is greatly appreciated.

Best regards

(from Kenneth_Oestrup)

[PARTHIBAN_CHINN]

These messages are just warning messages in BGP which is added in 15.x code.[This is used for general BGP loop prevention--Route Reflectors]

In 12.X code these warning messages are not added in Default Log filter events.





09/17/2013 14:37:18.16 A route can not be advertised because its next hop is the same as the

address of the peer to which it was being sent.

VR: 0x00000002

Neighbor index: 15

Next Hop Address: 202.166.192.150







This messages can be turned off with the below commands and verified:



configure log filter "DefaultFilter" add exclude events "BGP.PolicyMgr.RtNotAdvertNHSameTxPeer"

show log counters "BGP.PolicyMgr.RtNotAdvertNHSameTxPeer"

omponent SubComponent Condition Severity Occurred I Ntfd

---------- ------------ ----------------------- ------------- -------- - ----

GP PolicyMgr RtNotAdvertNHSameTxPeer Warning 0 N 0 ------------------------------------By Default the warning messages are turned on in 15.x code [Symbol Y]





12.6.2.10 doesn’t have this filter events in default filter:



X480. # configure log filter "DefaultFilter" add events bgp.



"bgp.outUpdt.intUpdtQRtToRRC" "bgp.outUpdt.intUpdtQWith"

"bgp.outUpdt.intUpdtRtBest" "bgp.outUpdt.intUpdtWith"

"bgp.outUpdt.localRtQExt" "bgp.outUpdt.localRtQInt"

"bgp.outUpdt.procInputUpdt" "bgp.outUpdt.qWithFiltered"

"bgp.outUpdt.qWithRROid" "bgp.outUpdt.rmDelNotiQRtExt"

"bgp.outUpdt.rmDelNotiRtQInt" "bgp.outUpdt.rmNotifQRtInt"

"bgp.outUpdt.rmNotiQRtExt" "bgp.outUpdt.rmNotiRtModQExt"

"bgp.outUpdt.rmNotiRtModQInt" "bgp.outUpdt.rtAdvQ"

"bgp.outUpdt.rtWithQ" "bgp.outUpdt.SndEOR"

"bgp.outUpdt.suppWithTx" "bgp.pgrpCreatFail"

"bgp.pgrpDelErr" "bgp.PlcyMgrMsg"

"bgp.ReusePeerCtrlBlk" "bgp.setMhopErr"

"bgp.setPeerObjErr" "bgp.setPgrpErr"

"bgp.setRtrObjErr" "bgp.staleDampRt"

"bgp.staleNHRt" "bgp.tstPeerErr"

"bgp.tstPgrpErr" "bgp.tstRtrObjErr"

"bgp.updtPgrpErr"





15.x has got a new filter BGP.PolicyMgr :



configure log filter "DefaultFilter" add events BGP.PolicyMgr

Component to add or delete

"BGP.PolicyMgr"

Component condition add or delete

"BGP.PolicyMgr.ActvRtMapNotSuprt"

"BGP.PolicyMgr.AggrRtMatchCfgAdvrtMap"

"BGP.PolicyMgr.AggrRtNotAdvertIndvl"

"BGP.PolicyMgr.ChgSoftResetEfctvRstrt"

"BGP.PolicyMgr.CompileRglrExprsnFail"

"BGP.PolicyMgr.CreatAggrTblMIBRowFail"

"BGP.PolicyMgr.CreatRecalcAggrRtFail"

"BGP.PolicyMgr.CreatRtMapTblMIBRowFail"

"BGP.PolicyMgr.DeactvIPPfxMIBRowFail"

"BGP.PolicyMgr.DeactvMIBRowFail"

"BGP.PolicyMgr.DenyRtByPlcy"

"BGP.PolicyMgr.DfltRtOrigInactvNoMatch"

"BGP.PolicyMgr.ExecRglrExprsnFail"

"BGP.PolicyMgr.FndActvRtMapFail"

"BGP.PolicyMgr.InitRsrcFail"

"BGP.PolicyMgr.ModCfgTblMIBRowCfgInv"

"BGP.PolicyMgr.ModCfgTblMIBRowRtMapInv"

"BGP.PolicyMgr.NHSelfCfgOvrrd3rdParty"

"BGP.PolicyMgr.ORFCmnPartCntnInvVal"

"BGP.PolicyMgr.ORFPfxEntCntnInvVal"

"BGP.PolicyMgr.PeerGrpDefImprtPlcy"

"BGP.PolicyMgr.PrvntRtMEDChgFmWrap"

"BGP.PolicyMgr.RecalcARORsrcFail"

"BGP.PolicyMgr.RecalcORFRsrcFail"

"BGP.PolicyMgr.RecvUpdtNonCfdASPathSeg"

"BGP.PolicyMgr.RemAllORFEntNotExist"

"BGP.PolicyMgr.RemORFEntNotExist"

"BGP.PolicyMgr.RtNotAdvertDstIPSameNH"

"BGP.PolicyMgr.RtNotAdvertNHSameTxPeer"

"BGP.PolicyMgr.RtNotAggrCntnSNPA"

"BGP.PolicyMgr.RtNotAggrInactv"

"BGP.PolicyMgr.RxUpdtEBGPOneHopAwayInv"

"BGP.PolicyMgr.RxUpdtNLRIInv"

[Cavan]

Same warning message on our router. Currently, just suppressing the warning.. Is that wise? Any more thoughts on this?

[EtherNation_Use]

Create Date: Jun 22 2012 6:55AM

I haven't seen this error, since i started using "next-hop-self" for iBGP peer sessions.

Now when disabling next-hop self for iBGP, the message starts showing up again.

From what I understand, this error is telling me, that I cannot re-advertise a route back to the same router that advertised it. (loop prevention). This happens with iBGP sessions without next-hop-self. Is this just the "split horizon rule", being logged as a warning approx. 1/sec.

Would it be alright to just supress this warning?

(from Kenneth_Oestrup)

[EtherNation_Use]

Create Date: Mar 7 2012 3:01AM

Without having seen your config from the X480 have you looked at :

if you are sending with the next-hop-self option enabled to the E-BGP upstream peer ?

conf bgp nei < peer-ip address > next-hop-self

Feel free to contact me on BGP issues on XoS. I have some experience with the subject 🙂

email erik at bais dot name

Regards,
Erik Bais (from Erik_Bais)