Configuration Guide for Cisco NCS 1014, IOS XR Releases 26.x.x

Last link flap detection

Updated: June 18, 2026

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This section lists the output formats, supported controllers, and operational details for the last link flap detection parameter in Cisco NCS 1014 transponder controllers.

Table 1. Feature History
Feature Name	Release Information	Feature Description
Last Link Flap Detection for Transponder Controllers	Cisco IOS XR Release 24.4.1	This feature introduces the detection of the last link flap for various transponder controllers. It provides the elapsed time since the occurrence of the last flap for each controller in the `show controllers` output. Link flap refers to the state transition of controllers from UP state to another state or from other states to UP state. This information enables network administrators to effectively monitor and troubleshoot signal stability and performance across the network. Parameter added: Last link flappedvalue

Link flap refers to the state transition of controllers from UP state to another state or from other states to UP state. The common cause is related to bad, unsupported, or nonstandard cable or Small Form-Factor Pluggable (SFP) or related to other link synchronization issues. The cause for link flapping can be intermittent or permanent.

NCS 1014 node detects the flapping of link in a signal for various transponder controllers. It provides the time that is elapsed from the occurrence of the last link flap through the last link flapped parameter in the show controllers output.

The show controller output displays the time-elapsed value for the last link flap in seconds, minutes, hours, days, weeks, and years based on the occurrence of the event.


Examples of last link flap value	Meaning of the value
00:00:10	Last link flapped 10 seconds ago.
1d12h	Last link flapped one day and 12 hours ago.
1y00w	Last link flapped one year ago.

The transponder controllers supporting the last link flap parameters are:

Ethernet
CoherentDSP
ODU
OTU
Optics

Output examples for each controller

Ethernet controller

The output provides information about a link flap on Ethernet controller that happened one year ago. It highlights the Last link flapped value in 1y00w format for show controllers TenGigECtrlr 0/1/0/0 .

RP/0/0/CPU0:ios#show controllers TenGigECtrlr 0/1/0/0 
Fri Sep 27 14:38:16.645 IST 
Operational data for interface TenGigECtrlr0/1/0/0: 
State: 
    Administrative state: enabled 
    Operational state: Up 
    Maintenance: Enabled 
    AINS Soak: None 
    Insert Idle Ingress: Disabled 
    Insert Idle Egress: Disabled 
    Last link flapped: 1y00w

Optics controller

The output provides information about a link flap on optics controller that happened four seconds ago. It highlights the Last link flapped value in the HH:MM:SS format for show controllers Optics 0/2/0/2 .

RP/0/0/CPU0:ios#show controllers Optics 0/2/0/2 
Thu Oct 10 12:39:37.767 UTC 
Controller State: Up 
Transport Admin State: In Service 
Laser State: On 
LED State: Green 
Last link flapped: 00:00:04 
         Optics not present 
         Optics Type: Unavailable 
         DWDM Carrier Info: Unavailable, MSA ITU Channel= Unavailable, Frequency= Unavailable , Wavelength= Unavailable 
         TX Power = Unavailable 
         RX Power = Unavailable

OTU controller

The output provides information about a link flap on OTU controller that happened ten seconds ago. It highlights the Last link flapped value in the HH:MM:SS format show controllers OTU4 0/0/0/6 .

RP/0/0/CPU0:ios#show controllers OTU4 0/0/0/6 
Thu Oct 10 12:57:13.777 UTC 
Port                                            : OTU4 0/0/0/6 
Controller State                                : Up 
LED state                                       : Not Applicable 
Last link flapped                               : 00:00:10 
Inherited Secondary State                       : Normal 
Configured Secondary State                      : Normal 
Derived State                                   : In Service 
Loopback mode                                   : None 
BER Thresholds                                  : SF = 1.0E-6  SD = 1.0E-7 
Performance Monitoring                          : Enable
Alarm Information: 
LOS = 0 LOF = 0 LOM = 0 
OOF = 0 OOM = 0 AIS = 0 
IAE = 0 BIAE = 0        SF_BER = 0 
SD_BER = 0      BDI = 0 TIM = 0 
FECMISMATCH = 0 FEC-UNC = 0     FLEXO_GIDM = 0 
FLEXO-MM = 0    FLEXO-LOM = 0   FLEXO-RDI = 0 
FLEXO-LOF = 0 
Detected Alarms                                 : None

ODU controller

The output provides information about a link flap on ODU controller that happened 52 seconds ago. It highlights the Last link flapped value in the HH:MM:SS format show controllers ODU4 0/0/0/6 .

RP/0/0/CPU0:ios#show controllers ODU4 0/0/0/6 
Thu Oct 10 12:57:55.717 UTC 
Port                                            : ODU4 0/0/0/6 
Controller State                                : Up 
LED state                                       : Not Applicable 
Last link flapped                               : 00:00:52 
Inherited Secondary state                       : Normal 
Configured Secondary state                      : Normal 
Derived State                                   : In Service 
Loopback mode                                   : None 
BER Thresholds                                  : SF = 1.0E-6  SD = 1.0E-7
Performance Monitoring                          : Disable 
Path Monitoring Mode                            : Non-Intrusive Monitor 
PM TIM-CA state                                 : Disable 
Alarm Information: 
AIS = 0 IAE = 0 BIAE = 0 
SF_BER = 0      SD_BER = 0      BDI = 0 
OCI = 0 LCK = 0 PTIM = 0 
TIM = 0 CSF = 0 GFP LFD = 0 
GFP LOCS = 0    GFP LOCCS = 0   GFP UPM = 0 
Detected Alarms                                 : None

ODU-FLEX controller

The output provides information about a link flap on ODU-FLEX controller that happened one minute and 35 seconds ago. It highlights the Last link flapped value in the HH:MM:SS format show controllers ODU-FLEX 0/3/0/0/* .

RP/0/RP0/CPU0:ios#show controllers ODU-FLEX 0/3/0/0/* 
Thu Oct 10 16:25:20.008 IST 
Port                                            : ODU-FLEX 0/3/0/0/1 
Controller State                                : Up 
Last link flapped                               : 00:01:35  
Inherited Secondary state                       : Normal 
Configured Secondary state                      : Normal 
Derived State                                   : In Service 
Loopback mode                                   : None 
BER Thresholds                                  : SF = 1.0E-6  SD = 1.0E-7 
Performance Monitoring                          : Enable 
Path Monitoring Mode                            : Operational 
PM TIM-CA state                                 : Disable

CoherentDSP controller

The output provides information about a link flap on coherentDSP controller that happened one day and 12 hours ago. It highlights the Last link flapped value in 1d12h format for show controllers coherentDSP 0/2/0/0 .

RP/0/RP0/CPU0:ios#show  controllers coherentDSP 0/2/0/0
Tue Nov 26 06:20:08.673 UTC

Port                                            : CoherentDSP 0/2/0/0
Controller State                                : Up
Last link flapped                               : 1d12h

Inherited Secondary State                       : Normal
Configured Secondary State                      : Normal
Derived State                                   : In Service
Loopback mode                                   : None
BER Thresholds                                  : SF = 1.0E-5  SD = 1.0E-7
Performance Monitoring                          : Enable
Bandwidth                                       : 800.0Gb/s
Client Network mapping Type                     : Ethernet

Alarm Information:
LOS = 16        LOF = 0 LOM = 0
OOF = 0 OOM = 0 AIS = 0
IAE = 0 BIAE = 0        SF_BER = 0
SD_BER = 0      BDI = 0 TIM = 0
FECMISMATCH = 0 FEC-UNC = 2     FLEXO_GIDM = 0
FLEXO-MM = 0    FLEXO-LOM = 0   FLEXO-RDI = 15
FLEXO-LOF = 96
Detected Alarms                                 : None

Bit Error Rate Information
PREFEC  BER                                     : 1.52E-04
POSTFEC BER                                     : 0.00E+00
Q-Factor                                        : 11.20 dB

Q-Margin                                        : 4.80 dB

Instantaneous Q-Margin                          : 4.80 dB

TTI :
Remote hostname                         : Node126
Remote interface                        : CoherentDSP 0/2/0/0
Remote IP addr                          : 0.0.0.0

FEC mode                                        : Soft-Decision 15

Flexo-Mode                                      : Enable
Flexo Details:
Tx GID                                  : 1
TX IID                                  : 1, 2, 3, 4, 5, 6, 7, 8,
Rx GID                                  : 1
RX IID                                  : 1, 2, 3, 4, 5, 6, 7, 8,

AINS Soak                                       : None
AINS Timer                                      : 0h, 0m
AINS remaining time                             : 0 seconds

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