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BGP Flapping / Carrier issue

massimo.disanto
Level 1
Level 1

Hello All,

I'm having a problem with my carrier.

My router is showing short BGP flaps every days but carrier router installed at my office is not showing any down ( this is a L2 connection and I have BGP directly with remote site ).

Logs of 1st July is due to a change port configuration, so it's not a fault.

What I need is give evidence to Carrier that their line is causing my BGP flapping every day.

Thanks in advance to all.

RGDS Massimo

My router logs:

ion sent
Jul  3 16:24:07: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Up
Jul  6 02:02:22: %BGP-3-NOTIFICATION: received from neighbor 57.21.26.29 4/0 (hold time expired) 0 bytes
Jul  6 02:02:22: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Down BGP Notification received
Jul  6 02:02:22: %BGP_SESSION-5-ADJCHANGE: neighbor 57.21.26.29 IPv4 Unicast topology base removed from session  BGP Notification received
Jul  6 02:02:46: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Up
Jul  6 02:06:52: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Down BGP Notification sent
Jul  6 02:06:52: %BGP-3-NOTIFICATION: sent to neighbor 57.21.26.29 4/0 (hold time expired) 0 bytes
Jul  6 02:06:52: %BGP_SESSION-5-ADJCHANGE: neighbor 57.21.26.29 IPv4 Unicast topology base removed from session  BGP Notification sent
Jul  6 02:07:01: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Up

Carrier's Router Logs:

*Jul  1 13:04:32.491: %LINK-3-UPDOWN: Interface GigabitEthernet0/1, changed state to down

*Jul  1 13:04:33.491: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/1, changed state to down

*Jul  1 13:04:35.775: %LINK-3-UPDOWN: Interface GigabitEthernet0/1, changed state to up

*Jul  1 13:04:36.775: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/1, changed state to up

*Jul  1 13:04:42.947: %SYS-5-SCHEDULED_RELOAD_CANCELLED:  Scheduled reload cancelled at 13:04:42 UTC Fri Jul 1 2016

10 Replies 10

Vinit Jain
Cisco Employee
Cisco Employee

Hello Massimo

Could you please try to ping the remote IP with the size of the MTU and df-bit set.

ping 57.21.26.29 size 1500 df-bit repeat 100  (assuming your interface MTU is 1500)

if the ping doesn't go through, then the problem is with your MTU settings in the path.

also, is your BGP flapping every few minutes?

Thanks
--Vinit

Hello Vinit,

thanks for your feedback, BGP is flapping randomically every 1 or 2 days.

But on same days is flapping more frequently

Jun 29 03:12:12: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Up
Jun 29 03:17:27: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Down BGP Notification sent
Jun 29 03:17:27: %BGP-3-NOTIFICATION: sent to neighbor 57.21.26.29 4/0 (hold time expired) 0 bytes
Jun 29 03:17:27: %BGP_SESSION-5-ADJCHANGE: neighbor 57.21.26.29 IPv4 Unicast topology base removed from session  BGP Notification sent
Jun 29 03:17:51: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Up
Jun 29 03:34:25: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Down BGP Notification sent
Jun 29 03:34:25: %BGP-3-NOTIFICATION: sent to neighbor 57.21.26.29 4/0 (hold time expired) 0 bytes
Jun 29 03:34:25: %BGP_SESSION-5-ADJCHANGE: neighbor 57.21.26.29 IPv4 Unicast topology base removed from session  BGP Notification sent
Jun 29 03:34:56: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Up
Jun 29 03:37:58: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Down BGP Notification sent
Jun 29 03:37:58: %BGP-3-NOTIFICATION: sent to neighbor 57.21.26.29 4/0 (hold time expired) 0 bytes
Jun 29 03:37:58: %BGP_SESSION-5-ADJCHANGE: neighbor 57.21.26.29 IPv4 Unicast topology base removed from session  BGP Notification sent
Jun 29 03:38:10: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Up
Jun 29 03:42:26: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Down BGP Notification sent
Jun 29 03:42:26: %BGP-3-NOTIFICATION: sent to neighbor 57.21.26.29 4/0 (hold time expired) 0 bytes
Jun 29 03:42:26: %BGP_SESSION-5-ADJCHANGE: neighbor 57.21.26.29 IPv4 Unicast topology base removed from session  BGP Notification sent
Jun 29 03:42:37: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Up
Jun 29 03:50:26: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Down BGP Notification sent
Jun 29 03:50:26: %BGP-3-NOTIFICATION: sent to neighbor 57.21.26.29 4/0 (hold time expired) 0 bytes
Jun 29 03:50:26: %BGP_SESSION-5-ADJCHANGE: neighbor 57.21.26.29 IPv4 Unicast topology base removed from session  BGP Notification sent
Jun 29 03:50:36: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Up
Jun 29 13:17:21: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Down BGP Notification sent
Jun 29 13:17:21: %BGP-3-NOTIFICATION: sent to neighbor 57.21.26.29 4/0 (hold time expired) 0 bytes
Jun 29 13:17:21: %BGP_SESSION-5-ADJCHANGE: neighbor 57.21.26.29 IPv4 Unicast topology base removed from session  BGP Notification sent
Jun 29 13:17:29: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Up
Jun 29 13:58:09: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Down BGP Notification sent
Jun 29 13:58:09: %BGP-3-NOTIFICATION: sent to neighbor 57.21.26.29 4/0 (hold time expired) 0 bytes
Jun 29 13:58:09: %BGP_SESSION-5-ADJCHANGE: neighbor 57.21.26.29 IPv4 Unicast topology base removed from session  BGP Notification sent
Jun 29 13:58:29: %BGP-3-NOTIFICATION: received from neighbor 57.21.26.29 active 2/8 (no supported AFI/SAFI) 3 bytes 000000
Jun 29 13:58:29: %BGP_SESSION-5-ADJCHANGE: neighbor 57.21.26.29 IPv4 Unicast topology base removed from session  BGP Notification received
Jun 29 13:58:32: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Up
Jun 29 14:02:01: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Down BGP Notification sent
Jun 29 14:02:01: %BGP-3-NOTIFICATION: sent to neighbor 57.21.26.29 4/0 (hold time expired) 0 bytes
Jun 29 14:02:01: %BGP_SESSION-5-ADJCHANGE: neighbor 57.21.26.29 IPv4 Unicast topology base removed from session  BGP Notification sent
Jun 29 14:02:12: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Up
Jun 29 14:03:34: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Down BGP Notification sent
Jun 29 14:03:34: %BGP-3-NOTIFICATION: sent to neighbor 57.21.26.29 4/0 (hold time expired) 0 bytes
Jun 29 14:03:34: %BGP_SESSION-5-ADJCHANGE: neighbor 57.21.26.29 IPv4 Unicast topology base removed from session  BGP Notification sent
Jun 29 14:03:48: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Up
Jun 29 14:07:35: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Down BGP Notification sent
Jun 29 14:07:35: %BGP-3-NOTIFICATION: sent to neighbor 57.21.26.29 4/0 (hold time expired) 0 bytes
Jun 29 14:07:35: %BGP_SESSION-5-ADJCHANGE: neighbor 57.21.26.29 IPv4 Unicast topology base removed from session  BGP Notification sent
Jun 29 14:08:08: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Up
Jun 29 14:29:37: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Down BGP Notification sent
Jun 29 14:29:37: %BGP-3-NOTIFICATION: sent to neighbor 57.21.26.29 4/0 (hold time expired) 0 bytes
Jun 29 14:29:37: %BGP_SESSION-5-ADJCHANGE: neighbor 57.21.26.29 IPv4 Unicast topology base removed from session  BGP Notification sent
Jun 29 14:30:24: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Up
Jul  1 11:53:24: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Down Interface flap
Jul  1 11:53:24: %BGP_SESSION-5-ADJCHANGE: neighbor 57.21.26.29 IPv4 Unicast topology base removed from session  Interface flap
Jul  1 11:53:33: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Up
Jul  1 13:38:12: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Down Interface flap
Jul  1 13:38:12: %BGP_SESSION-5-ADJCHANGE: neighbor 57.21.26.29 IPv4 Unicast topology base removed from session  Interface flap
Jul  1 13:38:28: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Up
Jul  3 08:17:42: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Down BGP Notification sent
Jul  3 08:17:42: %BGP-3-NOTIFICATION: sent to neighbor 57.21.26.29 4/0 (hold time expired) 0 bytes
Jul  3 08:17:42: %BGP_SESSION-5-ADJCHANGE: neighbor 57.21.26.29 IPv4 Unicast topology base removed from session  BGP Notification sent
Jul  3 08:21:59: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Up
Jul  3 16:19:34: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Down BGP Notification sent
Jul  3 16:19:34: %BGP-3-NOTIFICATION: sent to neighbor 57.21.26.29 4/0 (hold time expired) 0 bytes
Jul  3 16:19:34: %BGP_SESSION-5-ADJCHANGE: neighbor 57.21.26.29 IPv4 Unicast topology base removed from session  BGP Notification sent
Jul  3 16:24:07: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Up
Jul  6 02:02:22: %BGP-3-NOTIFICATION: received from neighbor 57.21.26.29 4/0 (hold time expired) 0 bytes
Jul  6 02:02:22: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Down BGP Notification received
Jul  6 02:02:22: %BGP_SESSION-5-ADJCHANGE: neighbor 57.21.26.29 IPv4 Unicast topology base removed from session  BGP Notification received
Jul  6 02:02:46: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Up
Jul  6 02:06:52: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Down BGP Notification sent
Jul  6 02:06:52: %BGP-3-NOTIFICATION: sent to neighbor 57.21.26.29 4/0 (hold time expired) 0 bytes
Jul  6 02:06:52: %BGP_SESSION-5-ADJCHANGE: neighbor 57.21.26.29 IPv4 Unicast topology base removed from session  BGP Notification sent
Jul  6 02:07:01: %BGP-5-ADJCHANGE: neighbor 57.21.26.29 Up

Thanks for the reply. Could you please share the below logs:

- show version

- show run interface <int-num>   // Interface where the provider is connected

- show inter <int-num>

Since when are you seeing the problem? 

Regards

Vinit

Thanks
--Vinit

Hi,

do you need physical or logical interface?

RGDS

MDS

Hi all,

I have the same problem ! 

CE(CISCO2911) -> PE(CISCO7606s) directly connected with two interfaces GigabitEthernet, and value MTU configured 1550 both directions.

Someone have idea how can solved this possible problem ?

regards

Sérgio Garcia

Hello Vinit,

problem is on going for last 2 months.

Here below info you required,

thanks a lot for support

Massimo

XXXX#sh vers
Cisco IOS Software, C2900 Software (C2900-UNIVERSALK9-M), Version 15.2(4)M8, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2015 by Cisco Systems, Inc.
Compiled Thu 02-Apr-15 14:11 by prod_rel_team

ROM: System Bootstrap, Version 15.0(1r)M15, RELEASE SOFTWARE (fc1)

pmpm198 uptime is 6 weeks, 4 days, 2 hours, 13 minutes
System returned to ROM by reload
System restarted at 13:46:08 GMT+2 Sat May 21 2016
System image file is "flash:c2900-universalk9-mz.SPA.152-4.M8"
Last reload type: Normal Reload
Last reload reason: power-on

This product contains cryptographic features and is subject to United
States and local country laws governing import, export, transfer and
use. Delivery of Cisco cryptographic products does not imply
third-party authority to import, export, distribute or use encryption.
Importers, exporters, distributors and users are responsible for
compliance with U.S. and local country laws. By using this product you
agree to comply with applicable laws and regulations. If you are unable
to comply with U.S. and local laws, return this product immediately.

A summary of U.S. laws governing Cisco cryptographic products may be found at:
http://www.cisco.com/wwl/export/crypto/tool/stqrg.html

If you require further assistance please contact us by sending email to
export@cisco.com.

Cisco CISCO2921/K9 (revision 1.0) with 479232K/45056K bytes of memory.
Processor board ID FCZ174160L9
3 Gigabit Ethernet interfaces
1 terminal line
1 Virtual Private Network (VPN) Module
DRAM configuration is 64 bits wide with parity enabled.
255K bytes of non-volatile configuration memory.
250880K bytes of ATA System CompactFlash 0 (Read/Write)


License Info:

License UDI:

-------------------------------------------------
Device#   PID                   SN
-------------------------------------------------
*0        CISCO2921/K9          FCZ174160L9

Technology Package License Information for Module:'c2900'

-----------------------------------------------------------------
Technology    Technology-package           Technology-package
              Current       Type           Next reboot
------------------------------------------------------------------
ipbase        ipbasek9      Permanent      ipbasek9
security      securityk9    Permanent      securityk9
uc            uck9          Permanent      uck9
data          datak9        RightToUse     datak9

Configuration register is 0x2102


XXXX#sh run int Gi0/1
Building configuration...

Current configuration : 231 bytes
!
interface GigabitEthernet0/1
 description --- Carrier=CMC NETWORKS , Offer=Junxion EVPL Gold - FastE
 bandwidth 10000
 no ip address
 no ip redirects
 no ip proxy-arp
 load-interval 30
 duplex full
 speed 100
 no cdp enable
end

XXXX#sh run int Gi0/1.456
Building configuration...

Current configuration : 315 bytes
!
interface GigabitEthernet0/1.456
 description To bjnb813 - Gi7/1/1.456 - 10000K
 bandwidth 10000
 encapsulation dot1Q 456
 ip address 57.21.26.30 255.255.255.252
 no ip redirects
 no ip proxy-arp
 ip flow ingress
 ip flow egress
 service-policy input COUNT-IN
 service-policy output COS-OUT-SHAPED-Gi0/1.456
end

XXXX#sh int Gi0/1
GigabitEthernet0/1 is up, line protocol is up
  Hardware is CN Gigabit Ethernet, address is c067.af62.d811 (bia c067.af62.d811)
  Description: --- Carrier=CMC NETWORKS , Offer=Junxion EVPL Gold - FastE
  MTU 1500 bytes, BW 10000 Kbit/sec, DLY 100 usec,
     reliability 255/255, txload 29/255, rxload 23/255
  Encapsulation 802.1Q Virtual LAN, Vlan ID  1., loopback not set
  Keepalive set (10 sec)
  Full Duplex, 100Mbps, media type is RJ45
  output flow-control is unsupported, input 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 5d00h
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 28
  Queueing strategy: Class-based queueing
  Output queue: 0/1000/28 (size/max total/drops)
  30 second input rate 915000 bits/sec, 377 packets/sec
  30 second output rate 1150000 bits/sec, 380 packets/sec
     69810661 packets input, 1174635334 bytes, 0 no buffer
     Received 8015 broadcasts (0 IP multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 8015 multicast, 0 pause input
     62448383 packets output, 1023681974 bytes, 0 underruns
     0 output errors, 0 collisions, 0 interface resets
     8015 unknown protocol drops
     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
XXXX#sh int Gi0/1.456
GigabitEthernet0/1.456 is up, line protocol is up
  Hardware is CN Gigabit Ethernet, address is c067.af62.d811 (bia c067.af62.d811)
  Description: To bjnb813 - Gi7/1/1.456 - 10000K
  Internet address is 57.21.26.30/30
  MTU 1500 bytes, BW 10000 Kbit/sec, DLY 100 usec,
     reliability 255/255, txload 28/255, rxload 25/255
  Encapsulation 802.1Q Virtual LAN, Vlan ID  456.
  ARP type: ARPA, ARP Timeout 04:00:00
  Keepalive set (10 sec)
  Last clearing of "show interface" counters never

I dont see any drops on the interface that could be of concern. I do see that the router was rebooted 1.5 months ago. (6 weeks). Was the problem seen even before the reload.

Since this is a sub-interface, is there a switch in the middle as well that you manage or is it managed by provider?

please do share "show run | sec router bgp"

Regards

Vinit

Thanks
--Vinit

Hi,

the problem was on going also before the reboot.

Here below the command

XXXX#show run | sec router bgp
router bgp 65000
 bgp log-neighbor-changes
 timers bgp 15 45
 neighbor 57.21.26.29 remote-as 13879
 neighbor 57.21.26.29 description --- PE XXXXX
 !
 address-family ipv4
  network 10.185.160.56 mask 255.255.255.252
  redistribute eigrp 64603 route-map EIGRP2BGP
  neighbor 57.21.26.29 activate
  neighbor 57.21.26.29 send-community
  neighbor 57.21.26.29 route-map BGP-TAGGING-OUT out
 exit-address-family
XXXX#

RGDS Massimo

Hello Vinit,

ping is working fine, no MTU size

***************************

pmpm198#ping 57.21.26.29 size 1500 df-bit repeat 100
Type escape sequence to abort.
Sending 100, 1500-byte ICMP Echos to 57.21.26.29, timeout is 2 seconds:
Packet sent with the DF bit set
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Success rate is 100 percent (100/100), round-trip min/avg/max = 24/26/32 ms
pmpm198#

*******************************

RGDS Massimo

dudus20122
Level 1
Level 1

In my own case, the issue was caused by a BGP session that was configured on the local router but the remote peer was not yet configured.

Immediately after the remote peer was set up, the flapping stop.