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An NE40E Fails to Establish a BGP Peer Relationship with a ZTE Device

Publication Date:  2019-04-19 Views:  110 Downloads:  0

Issue Description

NE40E------ZTE device
The IBGP peer relationship fails to be set up between an NE40E and a ZTE device, and the status remains Idle.
[ZJTZ2-XJJ.R1]dis bgp peer

 BGP local router ID :
 Local AS number : 33320
 Total number of peers : 1               Peers in established state : 1

  Peer            V          AS  MsgRcvd  MsgSent  OutQ  Up/Down       State PrefRcv      4       33320        0        0     0 00:00:05        Idle       0
IGP routes are normal.
[ZJTZ2-XJJ.R1]dis ospf peer brief

         OSPF Process 1 with Router ID
                  Peer Statistic Information
 Area Id          Interface                        Neighbor id      State          Serial2/1/1/46:0              Full 

Configuration of the NE40E:
interface Serial2/1/1/46:0
 link-protocol ppp
 ip address
interface LoopBack0
 ip address
bgp 33320                                
 peer as-number 33320
Configuration of the ZTE device:
interface ce1-0/1:1
  ip mtu 1024
  ip address
interface loopback1
  ip address
router bgp 33320
  synchronization disable
  neighbor ibgp-peer peer-group
  neighbor ibgp-peer remote-as 33320
  neighbor ibgp-peer activate
  neighbor ibgp-peer update-source loopback1
  neighbor peer-group ibgp-peer

Handling Process

1. The idle status of the BGP peer relationship shows that the TCP connection fails to be set up. Ping between the NE40E and ZTE device to check whether routes are reachable.
TZ2[XJ]-XIANJU.R1#ping source
sending 5,100-byte ICMP echo(es) to,timeout is 2 second(s).
Success rate is 100 percent(5/5),round-trip min/avg/max= 1/2/10 ms.
It is found that the communication between the NE40E and ZTE device is normal.

2. Check the NE40E uses a direct connect interface to establish the BGP peer relationship while the ZTE device uses the loopback interface of the NE40E.
3. Run the debug bgp command. The command output shows that the NE40E receives both the notification packets destined for and the link rejection packets from the peer device. It is confirmed that the BGP peer establishment failure is caused by incorrect parameter settings on the peer device.
Dec  5 2017 15:03:49.80.2 ZJTZ2-XJJ.R1 RM/6/RMDEBUG:
        BGP: Received from (AS Number: 33320)
        (Displaying bytes from 1 to 21)
        00 15 03 06 05

Dec  5 2017 15:03:49.80.3 ZJTZ2-XJJ.R1 RM/6/RMDEBUG:
BGP.Public: Recv NOTIFICATION MSG from peer
Err/SubErr: 6/5 (CEASE/Connection Rejected)
After the loopback interface specified on the NE40E is used to establish a BGP peer relationship, the problem is resolved.

Root Cause

The configurations are inconsistent between the NE40E and ZTE device.


Run the peer connect loopback 0 command on the NE40E.


If peer relationships fail to be set up using dynamic routing protocols, such as BGP, use the debugging command to view the complete packet exchanges.