Deferred frames on full-duplex link on 3850

[Jeremy Dubrulle]

Hi,

I have a big amount of excess deferred frames on 3850. But my links are all full-duplex.

Here are the info : 

-the duplex and speeds are 100Mb and full hardcoded (on the other equipement too)

-with show int : we see output errors

-with show controllers ethernet-controller : we see excess defer frames

-with show int couters errors : we see xmit-err and outdiscards, with the same value

I've seen that this is a bug with 2950 : CSCea56745

But can it be a bug for the 3850? My version is IOS-XE 03.06.04.E

Thanks,

[Leo Laohoo]

Post the complete output to the command "sh controll e <PORT>".

[Jeremy Dubrulle]

Transmit GigabitEthernet1/0/38 Receive
5233035807536 Total bytes 4001008204979 Total bytes
8795303119 Unicast frames 10188657555 Unicast frames
5232926196504 Unicast bytes 4000775844073 Unicast bytes
1504868 Multicast frames 3380799 Multicast frames
96396586 Multicast bytes 231907018 Multicast bytes
206452 Broadcast frames 7092 Broadcast frames
13212928 Broadcast bytes 453888 Broadcast bytes
0 System FCS error frames 0 IpgViolation frames
0 MacUnderrun frames 0 MacOverrun frames
0 Pause frames 14 Pause frames
0 Cos 0 Pause frames 0 Cos 0 Pause frames
0 Cos 1 Pause frames 0 Cos 1 Pause frames
0 Cos 2 Pause frames 0 Cos 2 Pause frames
0 Cos 3 Pause frames 0 Cos 3 Pause frames
0 Cos 4 Pause frames 0 Cos 4 Pause frames
0 Cos 5 Pause frames 0 Cos 5 Pause frames
0 Cos 6 Pause frames 0 Cos 6 Pause frames
0 Cos 7 Pause frames 0 Cos 7 Pause frames
0 Oam frames 0 OamProcessed frames
0 Oam frames 0 OamDropped frames
2000060027 Minimum size frames 2229833628 Minimum size frames
2825818876 65 to 127 byte frames 4706161325 65 to 127 byte frames
569904288 128 to 255 byte frames 562960595 128 to 255 byte frames
211623252 256 to 511 byte frames 397293040 256 to 511 byte frames
123105281 512 to 1023 byte frames 263585863 512 to 1023 byte frames
3066515284 1024 to 1518 byte frames 2032216990 1024 to 1518 byte frames
0 1519 to 2047 byte frames 0 1519 to 2047 byte frames
0 2048 to 4095 byte frames 0 2048 to 4095 byte frames
0 4096 to 8191 byte frames 0 4096 to 8191 byte frames
0 8192 to 16383 byte frames 0 8192 to 16383 byte frames
0 16384 to 32767 byte frame 0 16384 to 32767 byte frame
0 > 32768 byte frames 0 > 32768 byte frames
0 Late collision frames 0 SymbolErr frames
1641069784 Excess Defer frames 0 Collision fragments
0 Good (1 coll) frames 0 ValidUnderSize frames
0 Good (>1 coll) frames 0 InvalidOverSize frames
0 Deferred frames 0 ValidOverSize frames
0 Gold frames dropped 0 FcsErr frames
0 Gold frames truncated
0 Gold frames successful
0 1 collision frames
0 2 collision frames
0 3 collision frames
0 4 collision frames
0 5 collision frames

0 6 collision frames
0 7 collision frames
0 8 collision frames
0 9 collision frames
0 10 collision frames
0 11 collision frames
0 12 collision frames
0 13 collision frames
0 14 collision frames
0 15 collision frames
0 Excess collision frames

LAST UPDATE 2250 msecs AGO

[Leo Laohoo]

That's not the complete output, I think.

[Jeremy Dubrulle]

I've edited the last post

[Leo Laohoo]

Are there any Total Output Drops in the command "sh interface <PORT>"?

[Jeremy Dubrulle]

#sh interfaces g1/0/38
GigabitEthernet1/0/38 is up, line protocol is up (connected)
Hardware is Gigabit Ethernet, address is 0041.d29b.f726 (bia 0041.d29b.f726)
Description: RT-WAN-OS
MTU 1500 bytes, BW 100000 Kbit/sec, DLY 100 usec,
reliability 249/255, txload 78/255, rxload 28/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 100Mb/s, media type is 10/100/1000BaseTX
input flow-control is off, output flow-control is unsupported
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:03, output never, output hang never
Last clearing of "show interface" counters 01:00:20
Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 2077677
Queueing strategy: Class-based queueing
Output queue: 0/40 (size/max)
5 minute input rate 11000000 bits/sec, 5380 packets/sec
5 minute output rate 30701000 bits/sec, 5493 packets/sec
19034086 packets input, 5254473087 bytes, 0 no buffer
Received 4075 broadcasts (4075 multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 4075 multicast, 0 pause input
0 input packets with dribble condition detected
19227771 packets output, 13303994150 bytes, 0 underruns
2077677 output errors, 0 collisions, 0 interface resets
61 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier, 0 pause output
0 output buffer failures, 0 output buffers swapped out

[Leo Laohoo]

reliability 249/255, txload 78/255, rxload 28/255

WTF is that????

Jeremy, you've got bigger problems.  The numerator should ALWAYS be 255.  If the value is less than 255 then you've got cabling issues.  

Fix this first and see if the congestion improves. 

"Total Output Drops" means that the downstream device is constantly sending a "pause" back to the switch and the data gets piled into a buffer.  Because there's too much "pause" being received this buffer gets full and the "outputs" gets "drop" by the switch.

You may need to configure QoS.

[Jeremy Dubrulle]

Ok yes I see that the reliability value is moving between 245 and 255. I'll check that.

To tell you everything, it's happening on 3 different ports, and I've just seen the reliability value fallen sometimes below 255 on all 3.

[Jeremy Dubrulle]

It can't be a cabling issue if it's on 3 ports ? It would be an incredible bad luck

And the duplex aren't mismatched

[Leo Laohoo]

It can't be a cabling issue if it's on 3 ports ?

You're incredibly bad luck to have three ports having bad cabling. 

3850 support a feature called TDR.  I recommend you use it. 

[Jeremy Dubrulle]

Yes thanks good idea. I've done it on two of the interfaces :

Interface Speed Local pair Pair length Remote pair Pair status
--------- ----- ---------- ------------------ ----------- --------------------
Gi1/0/8 100M Pair A   0 +/- 1 meters Pair A           Normal
                       Pair B   1 +/- 1 meters Pair B            Open
                       Pair C   0 +/- 1 meters N/A              Normal
                       Pair D   0 +/- 1 meters N/A              Normal

Interface Speed Local pair Pair length Remote pair Pair status
--------- ----- ---------- ------------------ ----------- --------------------
Gi1/0/38 100M Pair A     N/A N/A                             Not Completed
                         Pair B     156 +/- 1 meters Pair A    Short/Crosstalk
                         Pair C     0 +/- 1 meters N/A            Normal
                         Pair D     0 +/- 1 meters N/A            Normal

On the last interface, Gigabit too, it's not supported. My switch is a 3850 IOS-XE 03.06.04.E

[Leo Laohoo]

Gi1/0/8 cable fault nearest the switch port. 

Gi1/0/38 cable fault at the remote side ... 156 metres away.  (I don't believe that's the correct distance.)

[Jeremy Dubrulle]

Ok, for both, the distance is 1-2 meters. The third port is fiber, that's why it doesn't work.

I'll replace the cables at noon.

[Leo Laohoo]

TDR are only for copper cables.