Step 1: Display SCB Error Messages in the System Log File

An SCB failure can cause the fpx0 interface, the Ethernet connection to a management LAN, to go up and down.

Action

To display SCB error messages in the system log file, use the following CLI command:

user@host> show log messages

Sample Output

user@host> show log messages

Nov 19 04:35:29 host snmpd[353]: SNMPD_SEND_FAILURE: trap_io_send_trap_now: 
sendto: No route to host

Nov 19 04:35:29 host rpd[355]: task_connect: task BGP_209.192.168.0.21+179 addr 
192.168.0.21+179: No route to host

Nov 19 04:35:29 host snmpd[353]: SNMPD_SEND_FAILURE: trap_io_send_trap_now: 
sendto: No route to host

Nov 19 04:35:29 host rpd[355]: bgp_connect_start: connect 192.168.0.21 (Internal 
AS 209): No route to host

Nov 19 04:35:29 host snmpd[353]: SNMPD_SEND_FAILURE: trap_io_send_trap_now: 
sendto: No route to host

Nov 19 04:35:29 host last message repeated 9 times

Nov 19 04:35:29 host tnp.bootpd[369]: BOOTPD_BOOTSTRING: boot 1 scb.jbf

Nov 19 04:35:29 host tnp.tftpd[389]: TFTPD_INFO: tftp read from addr 2 po

rt 1024 file scb.jbf

Nov 19 04:35:31 host tnp.tftpd[389]: TFTPD_INFO: sent 1348 blocks of 1024 and 1 
block of 780 for file /usr/share/pfe/scb.jbf 

Nov 19 04:35:32 host mgd[387]: UI_CMDLINE_READ_LINE: user 'user', command 'show 
chassis scb '

Nov 19 04:35:34 host /kernel: fxp1: link media DOWN 10Mb / half-duplex

Nov 19 04:35:34 host snmpd[353]: SNMPD_SEND_FAILURE: trap_io_send_trap_now: 
sendto: No route to host

Nov 19 04:35:34 host rpd[355]: EVENT <UpDown> fxp1.0 index 1 <Broadcast 
Multicast> address #0 0.80.82.18.14.83

Nov 19 04:35:34 host mib2d[354]: SNMP_TRAP_LINK_DOWN: ifIndex 2, ifAdminStatus 
up(1), ifOperStatus down(2), ifName fxp1

Nov 19 04:35:34 host snmpd[353]: SNMPD_SEND_FAILURE: trap_io_send_trap_now: 
sendto: No route to host

Nov 19 04:35:34 host last message repeated 4 times

Nov 19 04:35:35 host /kernel: fxp1: media DOWN 100Mb / half-duplex

Nov 19 04:35:36 host /kernel: fxp1: link UP 100Mb / half-duplex

Nov 19 04:35:36 host snmpd[353]: SNMPD_SEND_FAILURE: trap_io_send_trap_now: 
sendto: No route to host

Nov 19 04:35:36 host rpd[355]: EVENT <UpDown> fxp1.0 index 1 <Up Broadcast 
Multicast> address #0 0.80.82.18.14.83

Nov 19 04:35:36 host mib2d[354]: SNMP_TRAP_LINK_UP: ifIndex 2, ifAdminStatus 
up(1), ifOperStatus up(1), ifName fxp1

Nov 19 04:35:36 host snmpd[353]: SNMPD_SEND_FAILURE: trap_io_send_trap_now: 
sendto: No route to host

Nov 19 04:35:36 host last message repeated 4 times

Nov 19 04:35:37 host /kernel: fxp1: link media DOWN 10Mb / half-duplex

Nov 19 04:35:37 host snmpd[353]: SNMPD_SEND_FAILURE: trap_io_send_trap_now: 
sendto: No route to host

Nov 19 04:35:37 host rpd[355]: EVENT <UpDown> fxp1.0 index 1 <Broadcast 
multicast> address #0 0.80.82.18.14.83

Nov 19 04:35:37 host mib2d[354]: SNMP_TRAP_LINK_DOWN: ifIndex 2, ifAdminStatus 
up(1), ifOperStatus down(2), ifName fxp1

Nov 19 04:35:37 host snmpd[353]: SNMPD_SEND_FAILURE: trap_io_send_trap_now: 
sendto: No route to host

Nov 19 04:35:37 host last message repeated 4 times

Nov 19 04:35:38 host /kernel: fxp1: media DOWN 100Mb / full-duplex

Nov 19 04:35:38 host /kernel: fxp1: link UP 100Mb / full-duplex

Nov 19 04:35:38 host snmpd[353]: SNMPD_SEND_FAILURE: trap_io_send_trap_now: 
sendto: No route to host

What It Means

The messages system log file records the time the failure or event occurred, the severity level, a code, and a message description. When the SCB fails, the fxp1 interface keeps going up and down. You can use the show log messages | match scb command to see error messages that are generated when an SCB fails or is offline. Use this information to diagnose a problem and to let the Juniper Networks Technical Assistance Center (JTAC) know what error messages were generated and the router events that occurred before and after the problem. For more information about system log messages, see the JUNOS System Log Messages Reference.