Active latency Monitor

[wgranada]

Good day all,

I have been trying to research this, I have found one good article but it seems that we have the same question.  I have a N3K-C3548P-XL and I activated Active Latency Monitor on it.  Current settings are

slot 1
=======

Sampling CLI issued at: 09/09/2025 11:33:02
Sampling interval: 5

slot 1
=======

Sampling CLI issued at: 09/09/2025 11:33:25
Threshold Avg: 1000000
Threshold Max: 2000000

I get this in the logs quite a lot:

2025 Sep 9 11:06:56 dc3-cme-sw1 %MTC_USD-3-LATENCY_MONITOR_MAX_THRESHOLD_EXCEEDED: Ethernet1/41 max latency 4294967270 exceeding threshold-max 2000000

When I look at latency monitor for this specific interface (eth1/41)

slot 1
=======

09/09/2025 11:34:39
Device instance 0

Ethernet1/41
============
5s 30s 1hr All Time
Min Latency (ns) 182 182 51 7
Max Latency (ns) 1428 1602 4294967270 4294967292
Avg Latency (ns) 197 197 316 293
Std Deviation n/a 0.00 5.57 4.24

I understand that at 5s the max latency on this interface is 1428ns and the Min  is 182ns, same with the 30s columns Min 182ns and Max 1602ns but the last 2...one hour and all time. There is no way in 1hrs time I get 42 billion.  How do I read this correctly or what does this mean?  I also have active buffering enabled to when I check the buffers for the same time latency is triggered.  the buffers for that time are 0 so it cannot be miroburst. I thought perhaps playing around with the sampling interval might help, changed it from 3 to 5 but still the same.  I guess I am asking how do I interpret this?

Thank you in advance!!

Warren

[balaji.bandi]

what is the port utilisation normally ?

show interface Ethernet1/41 
show hardware profile latency monitor summary

[wgranada]

Good question I didn't check when I first started this so not sure I want to say n/a for all but to be honest not sure

show interface Ehternet1/41

Ethernet1/41 is up
admin state is up, Dedicated Interface
Hardware: 100/1000/10000/40000 Ethernet, address: d0e0.4276.f07c (bia d0e0.4276.f050)
Description: DC3-CME-SW2_L3
Internet Address is 192.168.105.18/30
MTU 1500 bytes, BW 10000000 Kbit , DLY 10 usec
reliability 255/255, txload 2/255, rxload 1/255
Encapsulation ARPA, medium is broadcast
full-duplex, 10 Gb/s, media type is 10G
Beacon is turned off
Auto-Negotiation is turned on FEC mode is Auto
Input flow-control is off, output flow-control is off
Auto-mdix is turned off
Rate mode is dedicated
Switchport monitor is off
EtherType is 0x8100
EEE (efficient-ethernet) : n/a
admin fec state is auto, oper fec state is off
Last link flapped 104week(s) 2day(s)
Last clearing of "show interface" counters never
1 interface resets
Load-Interval #1: 30 seconds
30 seconds input rate 13360 bits/sec, 8 packets/sec
30 seconds output rate 83656872 bits/sec, 20793 packets/sec
input rate 13.36 Kbps, 8 pps; output rate 83.66 Mbps, 20.79 Kpps
Load-Interval #2: 5 minute (300 seconds)
300 seconds input rate 16440 bits/sec, 6 packets/sec
300 seconds output rate 94015192 bits/sec, 22487 packets/sec
input rate 16.44 Kbps, 6 pps; output rate 94.01 Mbps, 22.49 Kpps
RX
5526915287 unicast packets 3780882566 multicast packets 2 broadcast packets
9307797855 input packets 6878450352040 bytes
0 jumbo packets 0 storm suppression packets
0 runts 0 giants 0 CRC 0 no buffer
0 input error 0 short frame 0 overrun 0 underrun 0 ignored
0 watchdog 0 bad etype drop 0 bad proto drop 0 if down drop
0 input with dribble 0 input discard
0 Rx pause
0 Stomped CRC
TX
8856144352 unicast packets 685032982772 multicast packets 0 broadcast packets
693889127124 output packets 442062300408401 bytes
0 jumbo packets
0 output error 0 collision 0 deferred 0 late collision
0 lost carrier 0 no carrier 0 babble 0 output discard
0 Tx pause

show hardware profile latency monitor summary

slot 1
=======

09/09/2025 11:56:38
Device instance 0

Total Switch
============
5s 30s 1hr All Time
Min Latency (ns) 182 182 51 7
Max Latency (ns) 12380 12383 4294967270 4294967270
Avg Latency (ns) 259 243 393 310
Std Deviation 3.56 1.20 0.13 0.08

Ethernet1/1
===========
5s 30s 1hr All Time
Min Latency (ns) n/a n/a n/a n/a
Max Latency (ns) n/a n/a n/a n/a
Avg Latency (ns) n/a n/a n/a n/a
Std Deviation n/a n/a n/a n/a

Ethernet1/2
===========
5s 30s 1hr All Time
Min Latency (ns) 320 320 320 320
Max Latency (ns) 12378 12378 16778541 16778541
Avg Latency (ns) 1330 1194 1647 1629
Std Deviation n/a 6.43 47.47 43.50

Ethernet1/3
===========
5s 30s 1hr All Time
Min Latency (ns) n/a n/a n/a n/a
Max Latency (ns) n/a n/a n/a n/a
Avg Latency (ns) n/a n/a n/a n/a
Std Deviation n/a n/a n/a n/a

Ethernet1/4
===========
5s 30s 1hr All Time
Min Latency (ns) 193 193 94 94
Max Latency (ns) 277 305 1316 1786
Avg Latency (ns) 197 197 197 197
Std Deviation n/a 0.01 0.01 0.01

Ethernet1/5
===========
5s 30s 1hr All Time
Min Latency (ns) 193 193 82 82
Max Latency (ns) 277 305 4294967267 4294967267
Avg Latency (ns) 197 197 816 497
Std Deviation n/a 0.01 205.83 143.20

Ethernet1/6
===========
5s 30s 1hr All Time
Min Latency (ns) n/a n/a n/a n/a
Max Latency (ns) n/a n/a n/a n/a
Avg Latency (ns) n/a n/a n/a n/a
Std Deviation n/a n/a n/a n/a

Ethernet1/7
===========
5s 30s 1hr All Time
Min Latency (ns) n/a n/a n/a n/a
Max Latency (ns) n/a n/a n/a n/a
Avg Latency (ns) n/a n/a n/a n/a
Std Deviation n/a n/a n/a n/a

Ethernet1/8
===========
5s 30s 1hr All Time
Min Latency (ns) n/a n/a n/a n/a
Max Latency (ns) n/a n/a n/a n/a
Avg Latency (ns) n/a n/a n/a n/a
Std Deviation n/a n/a n/a n/a

Ethernet1/9
===========
5s 30s 1hr All Time
Min Latency (ns) 276 269 215 215
Max Latency (ns) 8570 8570 16778541 16778541
Avg Latency (ns) 1325 1310 1433 1387
Std Deviation n/a 2.65 192.23 135.96

Ethernet1/10
============
5s 30s 1hr All Time
Min Latency (ns) n/a n/a n/a n/a
Max Latency (ns) n/a n/a n/a n/a
Avg Latency (ns) n/a n/a n/a n/a
Std Deviation n/a n/a n/a n/a

Ethernet1/11
============
5s 30s 1hr All Time
Min Latency (ns) n/a n/a n/a n/a
Max Latency (ns) n/a n/a n/a n/a
Avg Latency (ns) n/a n/a n/a n/a
Std Deviation n/a n/a n/a n/a

Ethernet1/12
============
5s 30s 1hr All Time
Min Latency (ns) n/a n/a n/a n/a
Max Latency (ns) n/a n/a n/a n/a
Avg Latency (ns) n/a n/a n/a n/a
Std Deviation n/a n/a n/a n/a

Ethernet1/13
============
5s 30s 1hr All Time
Min Latency (ns) n/a n/a n/a n/a
Max Latency (ns) n/a n/a n/a n/a
Avg Latency (ns) n/a n/a n/a n/a
Std Deviation n/a n/a n/a n/a

Ethernet1/14
============
5s 30s 1hr All Time
Min Latency (ns) 193 193 81 81
Max Latency (ns) 277 1268 4294967265 4294967265
Avg Latency (ns) 197 197 877 543
Std Deviation n/a 0.01 227.10 161.96

Ethernet1/15
============
5s 30s 1hr All Time
Min Latency (ns) n/a n/a n/a n/a
Max Latency (ns) n/a n/a n/a n/a
Avg Latency (ns) n/a n/a n/a n/a
Std Deviation n/a n/a n/a n/a

Ethernet1/16
============
5s 30s 1hr All Time
Min Latency (ns) 222 222 194 194
Max Latency (ns) 289 292 1473 1473
Avg Latency (ns) 242 246 256 256
Std Deviation n/a 1.22 11.11 11.01

Ethernet1/17
============
5s 30s 1hr All Time
Min Latency (ns) 223 222 216 216
Max Latency (ns) 293 300 1313 1317
Avg Latency (ns) 243 245 261 262
Std Deviation n/a 0.79 10.99 10.73

Ethernet1/18
============
5s 30s 1hr All Time
Min Latency (ns) 224 223 195 194
Max Latency (ns) 283 294 1475 1475
Avg Latency (ns) 242 245 256 256
Std Deviation n/a 0.93 11.79 11.71

Ethernet1/19
============
5s 30s 1hr All Time
Min Latency (ns) 190 190 89 89
Max Latency (ns) 289 296 1317 1447
Avg Latency (ns) 195 195 195 195
Std Deviation n/a 0.01 0.01 0.01

Ethernet1/20
============
5s 30s 1hr All Time
Min Latency (ns) 190 190 159 159
Max Latency (ns) 284 316 1314 1468
Avg Latency (ns) 195 195 195 195
Std Deviation n/a 0.02 0.02 0.01

Ethernet1/21
============
5s 30s 1hr All Time
Min Latency (ns) 222 222 192 192
Max Latency (ns) 292 295 1331 1331
Avg Latency (ns) 241 246 255 255
Std Deviation n/a 1.50 11.76 11.72

Ethernet1/22
============
5s 30s 1hr All Time
Min Latency (ns) 190 190 189 189
Max Latency (ns) 283 1284 1316 1316
Avg Latency (ns) 195 195 195 195
Std Deviation n/a 0.01 0.06 0.05

Ethernet1/23
============
5s 30s 1hr All Time
Min Latency (ns) 223 222 185 185
Max Latency (ns) 274 300 1456 1492
Avg Latency (ns) 239 244 261 262
Std Deviation n/a 1.18 11.05 10.82

Ethernet1/24
============
5s 30s 1hr All Time
Min Latency (ns) 223 223 184 184
Max Latency (ns) 288 303 1448 1448
Avg Latency (ns) 242 245 262 263
Std Deviation n/a 1.44 11.00 10.78

Ethernet1/25
============
5s 30s 1hr All Time
Min Latency (ns) 223 220 188 186
Max Latency (ns) 383 1277 1305 1305
Avg Latency (ns) 290 304 297 297
Std Deviation n/a 5.80 4.09 4.18

Ethernet1/26
============
5s 30s 1hr All Time
Min Latency (ns) 193 192 186 186
Max Latency (ns) 292 1269 1444 1791
Avg Latency (ns) 236 258 248 248
Std Deviation n/a 15.27 9.60 9.97

Ethernet1/27
============
5s 30s 1hr All Time
Min Latency (ns) 190 190 155 155
Max Latency (ns) 285 319 1306 1358
Avg Latency (ns) 195 195 195 195
Std Deviation n/a 0.02 0.01 0.01

Ethernet1/28
============
5s 30s 1hr All Time
Min Latency (ns) 225 223 185 185
Max Latency (ns) 278 1260 1320 1451
Avg Latency (ns) 241 267 262 262
Std Deviation n/a 14.26 11.09 10.83

Ethernet1/29
============
5s 30s 1hr All Time
Min Latency (ns) 227 226 193 193
Max Latency (ns) 277 292 1317 1317
Avg Latency (ns) 243 247 258 258
Std Deviation n/a 0.88 11.81 11.71

Ethernet1/30
============
5s 30s 1hr All Time
Min Latency (ns) 223 222 215 215
Max Latency (ns) 385 1291 1356 1455
Avg Latency (ns) 305 311 306 306
Std Deviation n/a 4.16 3.50 3.52

Ethernet1/31
============
5s 30s 1hr All Time
Min Latency (ns) 228 222 195 195
Max Latency (ns) 384 495 1345 1453
Avg Latency (ns) 304 303 307 307
Std Deviation n/a 1.30 3.51 3.48

Ethernet1/32
============
5s 30s 1hr All Time
Min Latency (ns) 225 225 192 192
Max Latency (ns) 384 385 1352 1374
Avg Latency (ns) 297 304 307 307
Std Deviation n/a 1.01 3.42 3.48

Ethernet1/33
============
5s 30s 1hr All Time
Min Latency (ns) n/a n/a n/a n/a
Max Latency (ns) n/a n/a n/a n/a
Avg Latency (ns) n/a n/a n/a n/a
Std Deviation n/a n/a n/a n/a

Ethernet1/34
============
5s 30s 1hr All Time
Min Latency (ns) n/a n/a n/a n/a
Max Latency (ns) n/a n/a n/a n/a
Avg Latency (ns) n/a n/a n/a n/a
Std Deviation n/a n/a n/a n/a

Ethernet1/35
============
5s 30s 1hr All Time
Min Latency (ns) n/a n/a n/a n/a
Max Latency (ns) n/a n/a n/a n/a
Avg Latency (ns) n/a n/a n/a n/a
Std Deviation n/a n/a n/a n/a

Ethernet1/36
============
5s 30s 1hr All Time
Min Latency (ns) 283 273 214 214
Max Latency (ns) 289 309 1456 1456
Avg Latency (ns) 286 286 312 311
Std Deviation n/a 3.07 52.00 49.01

Ethernet1/37
============
5s 30s 1hr All Time
Min Latency (ns) 182 182 182 182
Max Latency (ns) 327 334 7609 7657
Avg Latency (ns) 187 188 189 187
Std Deviation n/a 0.04 0.82 0.29

Ethernet1/38
============
5s 30s 1hr All Time
Min Latency (ns) 245 245 245 245
Max Latency (ns) 383 399 70516 90986
Avg Latency (ns) 252 254 464 446
Std Deviation n/a 0.10 74.22 63.14

Ethernet1/39
============
5s 30s 1hr All Time
Min Latency (ns) 243 242 242 242
Max Latency (ns) 888 891 104341 189902
Avg Latency (ns) 263 263 448 461
Std Deviation n/a 0.18 54.42 58.83

Ethernet1/40
============
5s 30s 1hr All Time
Min Latency (ns) 182 182 182 182
Max Latency (ns) 193 325 1434 1434
Avg Latency (ns) 187 187 187 187
Std Deviation n/a 0.01 0.04 0.04

Ethernet1/41
============
5s 30s 1hr All Time
Min Latency (ns) 182 182 51 7
Max Latency (ns) 564 1348 4294967270 4294967270
Avg Latency (ns) 197 197 334 265
Std Deviation n/a 0.00 5.98 4.20

Ethernet1/42
============
5s 30s 1hr All Time
Min Latency (ns) n/a n/a n/a n/a
Max Latency (ns) n/a n/a n/a n/a
Avg Latency (ns) n/a n/a n/a n/a
Std Deviation n/a n/a n/a n/a

Ethernet1/43
============
5s 30s 1hr All Time
Min Latency (ns) 304 186 185 184
Max Latency (ns) 304 335 1437 1437
Avg Latency (ns) 304 299 333 333
Std Deviation n/a 11.05 22.81 21.85

Ethernet1/44
============
5s 30s 1hr All Time
Min Latency (ns) 267 247 245 245
Max Latency (ns) 380 975 1552 1552
Avg Latency (ns) 336 348 341 341
Std Deviation n/a 5.48 7.08 7.02

Ethernet1/45
============
5s 30s 1hr All Time
Min Latency (ns) 182 182 51 9
Max Latency (ns) 12380 12383 4294967265 4294967265
Avg Latency (ns) 324 292 409 334
Std Deviation n/a 0.06 5.70 4.01

Ethernet1/46
============
5s 30s 1hr All Time
Min Latency (ns) n/a n/a n/a n/a
Max Latency (ns) n/a n/a n/a n/a
Avg Latency (ns) n/a n/a n/a n/a
Std Deviation n/a n/a n/a n/a

Ethernet1/47
============
5s 30s 1hr All Time
Min Latency (ns) 185 183 182 182
Max Latency (ns) 305 418 1359 1374
Avg Latency (ns) 267 264 251 249
Std Deviation n/a 1.12 2.62 2.63

Ethernet1/48
============
5s 30s 1hr All Time
Min Latency (ns) 185 183 182 182
Max Latency (ns) 188 412 1797 1797
Avg Latency (ns) 186 216 224 222
Std Deviation n/a 13.93 29.66 27.72

I have 2 switches that sit on the edge SW1 and SW2, Ethernet1/41 is an interface between the 2 switches so if SW1 dies everything will route over SW2