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New Member

BGP looping

Dear all,

I have some problem, and would like your advice as below.

I tried to connect a few 1711 router connect together and use EBGP for the routing.

Problem is on the command

- router bgp 100

no synchronization

bgp log-neighbor-changes

network 10.61.177.0 mask 255.255.255.0

network 192.1.1.0

neighbor 10.61.177.69 remote-as 555

neighbor 192.1.1.6 remote-as 65127

I find that after clear the ip bgp * process and sh the ip route, it show all network 0.0.0.0 will be via 192.1.1.6.

Show ip route

Gateway of last resort is 192.1.1.6 to network 0.0.0.0

10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks

B 10.0.1.0/24 [20/0] via 10.61.177.69, 00:06:15

C 10.61.177.68/30 is directly connected, Vlan1

C 192.1.1.0/24 is directly connected, FastEthernet0

B* 0.0.0.0/0 [20/0] via 192.1.1.6, 00:06:15

sh ip bgp nei 192.1.1.6 advertised-routes

Network Next Hop Metric LocPrf Weight Path

*> 0.0.0.0 192.1.1.6 0 65127 65535 i

*> 10.0.1.0/24 10.61.177.69 0 0 555 i

*> 192.1.1.0 0.0.0.0 0 32768 i

I am not sure whether looping occurred on this router.

Can anyone have ideal on this case.

Thanks

2 REPLIES
Cisco Employee

Re: BGP looping

I'm not sure what the question is. Why is it wrong for this router to learn the default route from its peer in AS 65127. Could you please clearly state what the issue is.

Thanks,

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México 
Paseo de la Reforma 222 Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
New Member

Re: BGP looping

At the first time, maybe bgp looping occur by this default route, checked the neigbor router but no abnormally observed.

After I checked and found that the default route is propagated from the third EBGP router outisde, due to the command

router bgp xx

neighbor 192.xx.xx.xx default-originate

Therefore all the router observed the default route.

Now this question is solved, thanks for your replied.

Best Regards

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