Support Support Downloads Knowledge Base Case Manager My Juniper Community

Knowledge Base

Search our Knowledge Base sites to find answers to your questions.

Ask All Knowledge Base Sites All Knowledge Base Sites JunosE Defect (KA)Knowledge BaseSecurity AdvisoriesTechnical BulletinsTechnotes Sign in to display secure content and recently viewed articles

[MX] Unused ge- port goes up and down by itself

1

0

Article ID: KB33478 KB Last Updated: 03 Aug 2020Version: 3.0
Summary:

A pair of SNMP link up and down traps is seen on an unused ge- interface that is down and has no SFP/cable connection.

This is rare, but it can happen with ge- ports on NEO MIC[3D 20x 1GE(LAN) SFP] in MX5/10/40/80/104 platforms or MPCE/MPC2E in other MX platforms.

Symptoms:

SNMP link up/down trap is reported on an unused ge- interface that is down and has no SFP/cable connection.

User@MX> show chassis hardware

Hardware inventory:
Item             Version  Part number  Serial number     Description
FPC 1                     BUILTIN      BUILTIN           MPC BUILTIN
  MIC 0          REV 24   750-028392   xxxxxxx           3D 20x 1GE(LAN) SFP
    PIC 0                 BUILTIN      BUILTIN           10x 1GE(LAN) SFP
    PIC 1                 BUILTIN      BUILTIN           10x 1GE(LAN) SFP
Fan Tray                                                 Fan Tray

*** messages ***
Sep 19 08:50:51  MX rpd[1731]: EVENT <UpDown> ge-1/1/2 index 152 <Up Broadcast Multicast> address #0 40.71.83.f0.a6.8a
Sep 19 08:50:51  MX rpd[1733]: EVENT <UpDown> ge-1/1/2 index 152 <Up Broadcast Multicast> address #0 40.71.83.f0.a6.8a
Sep 19 08:50:51  MX rpd[1732]: EVENT <UpDown> ge-1/1/2 index 152 <Up Broadcast Multicast> address #0 40.71.83.f0.a6.8a
Sep 19 08:50:51  MX rpd[1730]: EVENT <UpDown> ge-1/1/2 index 152 <Up Broadcast Multicast> address #0 40.71.83.f0.a6.8a
Sep 19 08:50:51  MX rpd[1702]: EVENT <UpDown> ge-1/1/2 index 152 <Up Broadcast Multicast> address #0 40.71.83.f0.a6.8a
Sep 19 08:50:51  MX mib2d[1698]: SNMP_TRAP_LINK_UP: ifIndex 532, ifAdminStatus up(1), ifOperStatus up(1), ifName ge-1/1/2
Sep 19 08:50:52  MX rpd[1731]: EVENT <UpDown> ge-1/1/2 index 152 <Broadcast Multicast> address #0 40.71.83.f0.a6.8a
Sep 19 08:50:52  MX rpd[1733]: EVENT <UpDown> ge-1/1/2 index 152 <Broadcast Multicast> address #0 40.71.83.f0.a6.8a
Sep 19 08:50:52  MX rpd[1732]: EVENT <UpDown> ge-1/1/2 index 152 <Broadcast Multicast> address #0 40.71.83.f0.a6.8a
Sep 19 08:50:52  MX rpd[1730]: EVENT <UpDown> ge-1/1/2 index 152 <Broadcast Multicast> address #0 40.71.83.f0.a6.8a
Sep 19 08:50:52  MX rpd[1702]: EVENT <UpDown> ge-1/1/2 index 152 <Broadcast Multicast> address #0 40.71.83.f0.a6.8a
Sep 19 08:50:52  MX mib2d[1698]: SNMP_TRAP_LINK_DOWN: ifIndex 532, ifAdminStatus up(1), ifOperStatus down(2), ifName ge-1/1/2

User@MX > show interfaces ge-1/1/2 media
Physical interface: ge-1/1/2, Enabled, Physical link is Down
  Interface index: 152, SNMP ifIndex: 532, Generation: 155
  Description: to kopt secoundary_spare
  Link-level type: Ethernet, MTU: 1514, MRU: 1522, LAN-PHY mode, Speed: 100mbps, BPDU Error: None, MAC-REWRITE Error: None, Loopback: Disabled, Source filtering: Disabled, Flow control: Enabled, Auto-negotiation: Disabled, Remote fault: Online
  Pad to minimum frame size: Disabled
  Device flags   : Present Running Down
  Interface flags: Hardware-Down SNMP-Traps Internal: 0x0
  Link flags     : None
  CoS queues     : 8 supported, 8 maximum usable queues
  Hold-times     : Up 0 ms, Down 0 ms
  Damping        : half-life: 0 sec, max-suppress: 0 sec, reuse: 0, suppress: 0, state: unsuppressed
  Current address: 40:71:83:f0:a6:8a, Hardware address: 40:71:83:f0:a6:8a
  Last flapped   : 2018-09-19 08:50:52 JST (8w6d 12:47 ago)
  Input rate     : 0 bps (0 pps)
  Output rate    : 0 bps (0 pps)
  Active alarms  : LINK
  Active defects : LINK
Cause:

The issue is that only this port (ex. ge-1/1/2) has link flapping occasionally, while other ports are okay.  Electrical noise can trigger this. A possibility can be noisy hardware somewhere (around ge-1/1/2) on the board.

Without the SFP plugged in, there could be noise on the input that could change the "partner ability" register for auto negotiation. If a certain short sequence of bits is received, then the "partner ability" register can be updated (/C/ character), hence the fake link up/down event.  

Solution:

This link up/down snmp trap is only cosmetic, and can safely be ignored. Disabling the interface can be a workaround.

RMA is not necessary for rare occurrences, but MIC RMA is recommended for frequent occurrences.

Modification History:
2018-12-18: Minor, non-technical edit.
2020-08-03: Fixed typo in the cause section.
Comment on this article > Affected Products Browse the Knowledge Base for more articles related to these product categories. Select a category to begin.

Getting Up and Running with Junos

Getting Up and Running with Junos Security Alerts and Vulnerabilities Product Alerts and Software Release Notices Problem Report (PR) Search Tool EOL Notices and Bulletins JTAC User Guide Customer Care User Guide Pathfinder SRX High Availability Configurator SRX VPN Configurator Training Courses and Videos End User Licence Agreement Global Search