# BGP Falapping



## Tech_Supp (May 16, 2011)

Hi All I have two BGP session with ISP Pri and Secondary, both are terminated on L3 switch at our end,both l3 switches located on different geographycal locations.both L3 switches are having IBGP session with each other and EBGP with their respective ISP.

My both BGP sessions are flapping with ISP at specific time,first i m getting drops then BGP is got down for few seconds then after that it get stable and come up for last few months I am facing this issue

1.I raised query with media provider no issue in Trassmission Media
2.NO BGP configuration issue
3.No CPU and Memorty issue 
4.MTU also kept same both end

Please find the logs from my end device.


3-NOTIFICATION: sent to neighbor 10.3.32.93 4/0 (hold time expired) 0 bytes 
Aug 9 02:23:02.384 IST: %BGP-5-ADJCHANGE: neighbor 10.3.32.93 Up 
Aug 9 02:28:49.169 IST: %BGP-5-ADJCHANGE: neighbor 10.3.32.93 Down BGP Notification sent
Aug 9 02:28:49.169 IST: %BGP-3-NOTIFICATION: sent to neighbor 10.3.32.93 4/0 (hold time expired) 0 bytes 
Aug 9 02:29:21.113 IST: %BGP-5-ADJCHANGE: neighbor 10.3.32.93 Up 
Aug 9 02:29:33.419 IST: %BGP-5-ADJCHANGE: neighbor 10.3.32.93 Down BGP Notification sent
Aug 9 02:29:33.419 IST: %BGP-3-NOTIFICATION: sent to neighbor 10.3.32.93 4/0 (hold time expired) 0 bytes 
Aug 9 02:29:48.896 IST: %BGP-5-ADJCHANGE: neighbor 10.3.32.93 Up 



CONFIG

aaa session-id common
clock timezone IST 5 30
system mtu routing 1500
authentication mac-move permit
ip subnet-zero
no ip source-route
ip routing
no ip domain-lookup


interface GigabitEthernet0/2
description *** ISP Wvr Secondary ***
no switchport
ip address 10.3.32.94 255.255.255.252
media-type rj45
speed 100
duplex full



GigabitEthernet0/2 is up, line protocol is up (connected) 
Hardware is Gigabit Ethernet, address is fcfb.fbcf.bacb (bia fcfb.fbcf.bacb)
Description: ***ISP Wvr Secondary ***
Internet address is 10.3.32.94/30
MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec, 
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 100Mb/s, media type is 10/100/1000BaseTX
input flow-control is off, output flow-control is unsupported 
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:00, output 00:00:00, output hang never
Last clearing of "show interface" counters 1d21h
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 1000 bits/sec, 2 packets/sec
5 minute output rate 1000 bits/sec, 1 packets/sec
2533776 packets input, 1421520008 bytes, 0 no buffer
Received 134 broadcasts (0 IP multicasts)
0 runts, 56 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 0 multicast, 0 pause input
0 input packets with dribble condition detected
1489478 packets output, 155742815 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier, 0 PAUSE output
0 output buffer failures, 0 output buffers swapped out

router bgp 64759
no synchronization
bgp log-neighbor-changes
neighbor 10.3.32.93 remote-as 55410
neighbor 10.3.32.93 transport path-mtu-discovery
neighbor 10.3.32.93 description ***WIVR***
neighbor 10.3.32.93 timers 4 12
neighbor 10.3.32.93 route-map SETLP_VODA in
neighbor 10.3.32.93 route-map SETMED_VODA out



Please Help to resolve the issue.


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## Wand3r3r (Sep 17, 2010)

perhaps this will help
Troubleshooting Flapping BGP Routes (Recursive Routing Failure)  [IP Routing] - Cisco Systems


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## Tech_Supp (May 16, 2011)

Thanks for the link but i have already gone through the same still issue presist


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## Wand3r3r (Sep 17, 2010)

Any reason why both are set to 100mb when they say gigabit for the interface?
Makes me wonder if the line between doesn't support gigabit. Which in turn could be the cause of communication issues between the two.


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## Tech_Supp (May 16, 2011)

I have kept it 1000mb still BGP flaps


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## Tech_Supp (May 16, 2011)

It seems very difficult to resolve 47 views past 2 days and only one reply god help me!!!


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