This article discusses the Syslog message "tfeb[X] mic_mac_periodic:ge-x/y/z: ifd_mup" and troubleshooting steps to mitigate the logs.

MX lower end devices [MX5] having inbuilt TFEB which reports frequent flapping of interfaces along with logging below syslog message:

Hardware inventory:

Item            Version Part number Serial number    Description
TFEB 0                   BUILTIN     BUILTIN          Forwarding Engine Processor

LOGS:

Jul 3 09:48:55 device1 tfeb0 mic_mac_periodic:ge-1/0/1: ifd_mup
Jul 3 09:48:56 device1 tfeb0 ifp ge-1/0/1 ifd_mdown: 8918515655 ms
Jul 3 09:48:57 device1 tfeb0 mic_mac_periodic:ge-1/0/1: ifd_mup
Jul 3 09:48:58 device1 tfeb0 ifp ge-1/0/1 ifd_mdown: 8918517665 ms
Jul 3 09:48:59 device1 tfeb0 mic_mac_periodic:ge-1/0/1: ifd_mup
Jul 3 09:49:00 device1 tfeb0 ifp ge-1/0/1 ifd_mdown: 8918519665 ms

Jul 3 09:49:01 device1 tfeb0 ifp ge-1/0/1 ifd_mdown -------------------------------------->> INTERFACE GOING DOWN
Jul 3 09:49:02 device1 mib2d[2028]: SNMP_TRAP_LINK_DOWN: ifIndex 680, ifAdminStatus up(1), ifOperStatus down(2), ifName xe-1/2/0
Jul 3 09:49:03 device1 tfeb0 mic_mac_periodic:ge-1/0/1: ifd_mup ------------------------->> INTERFACE GOING UP

The carrier transitions count on the interface also increases: [which can be viewed by show interfaces extensive | match "ge-1/0/1"]

Physical interface: ge-1/0/1, Enabled, Physical link is Up

>>>> Carrier transitions: 44815, Errors: 0, Drops: 46557, Collisions: 0, Aged packets: 0, FIFO errors: 0, HS link CRC errors: 0, MTU errors: 0, Resource errors: 0

* Carrier transitions: Number of times that the interface has gone from down to up.

"mic_mac_periodic" – calls mac periodic routines for a link.
 

These log messages are because of frequent interface flaps happening due to an interface/fiber/transmission issue.

This is caused due to L1 issue. Please perform physical layer Troubleshooting to resolve the issue.

 To resolve the issue, check the following:

• Clean the fiber end to end between the two devices
• Try changing cable/transmission media to good cable to exclude bad or damaged cable issues.
• Try changing the SFP to see if the port stays stable on a new SFP to exclude bad or damaged SFP.
• Try moving the same SFP/fiber to another good known spare port on same router to exclude NIC card issues.
• Check duplex setting on both sides of devices. Make sure both are using full duplex.

Note: Perform the same steps on other end i.e to which the interface is connected to. 

 If the logs are seen after L1 Troubleshooting, open a case with JTAC Support for further investigation and assistance. This might need detailed investigation to rule out the possibility of hardware failure of the port.

2025-06-26: Minor, non-technical update

2023-04-14: Article created