Troubleshooting output drops on Cisco 7606-S

[zizou6500]

Hi Community,

I'm facing an issue of output drops and I'm looking for ideas/solutions to fix this. Below is the interface details : 

sh int gigabitEthernet 2/1
GigabitEthernet2/1 is up, line protocol is up (connected)
MTU 4470 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 1000Mb/s, media type is LH
input flow-control is off, output flow-control is off
Clock mode is auto
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:00, output 00:00:00, output hang never
Last clearing of "show interface" counters 20:37:50
Input queue: 0/1000/0/0 (size/max/drops/flushes); Total output drops: 545
Queueing strategy: fifo
Output queue: 0/1000 (size/max)
30 second input rate 257000 bits/sec, 153 packets/sec
30 second output rate 115000 bits/sec, 150 packets/sec
L2 Switched: ucast: 151226 pkt, 13976317 bytes - mcast: 406790 pkt, 55333580 bytes
L3 in Switched: ucast: 28242315 pkt, 23861594658 bytes - mcast: 1448761 pkt, 94740496 bytes mcast
L3 out Switched: ucast: 33417728 pkt, 26160315623 bytes mcast: 2181321 pkt, 160731409 bytes
30384032 packets input, 24034608433 bytes, 0 no buffer
Received 1963529 broadcasts (1449597 IP multicasts)
0 runts, 14302526 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 0 multicast, 0 pause input
0 input packets with dribble condition detected
36223875 packets output, 26355162646 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier, 0 pause output

[balaji.bandi]

It requires more information rather just interface output.

1.how these port connected and where it connected ( what device is this , Switch or router or provider network)

2. I have noticed you have Media Type LH, is this point to point to Link ( do you see same errors other side ?

3. Do you run any encryption ? on this device ?

4. can you post show version, show process cpu history and show process cpu | ex 0.00%

for other reference troubleshooting :

https://www.cisco.com/c/en/us/support/docs/routers/7200-series-routers/110850-queue-limit-output-drops-ios.html

[zizou6500]

 Hi,

Thank you for your help. Below the response to your questions : 

1.how these port connected and where it connected ( what device is this , Switch or router or provider network)

--> Router

2. I have noticed you have Media Type LH, is this point to point to Link ( do you see same errors other side ?)

-->Point to point // No errors on the other side

3. Do you run any encryption ? on this device ?

-->No

4. can you post show version, show process cpu history and show process cpu | ex 0.00%

sh version : 

Cisco CISCO7606-S (M8500) processor (revision 1.1) with 917504K/65536K bytes of memory.
Processor board ID FXS1703Q20X
BASEBOARD: RSP720
CPU: MPC8548_E, Version: 2.1, (0x80390021)
CORE: E500, Version: 2.2, (0x80210022)
CPU:1200MHz, CCB:400MHz, DDR:200MHz,
L1: D-cache 32 kB enabled
I-cache 32 kB enabled

Last reset from power-on
21 Virtual Ethernet interfaces
100 Gigabit Ethernet interfaces
16 Ten Gigabit Ethernet interfaces
3964K bytes of non-volatile configuration memory.

500472K bytes of Internal ATA PCMCIA card (Sector size 512 bytes).
Configuration register is 0x2102

show process cpu history

233333333332222233333333332222222222222223333333333111112222
100
90
80
70
60
50
40
30
20
10
0....5....1....1....2....2....3....3....4....4....5....5....6
0 5 0 5 0 5 0 5 0 5 0
CPU% per second (last 60 seconds)





1
648443445444356443447445453344344445343443446333443344444434
100
90
80
70
60
50
40
30
20 *
10 * * * ** * * * * *
0....5....1....1....2....2....3....3....4....4....5....5....6
0 5 0 5 0 5 0 5 0 5 0
CPU% per minute (last 60 minutes)
* = maximum CPU% # = average CPU%





111111111121111111111111111111211 111111121112111111111122111211111111
872379924608297189518498795293017777222572407620279329275801797034912377
100
90
80
70
60
50
40
30
20 ** *** *** ** *** * ***** * * * ** *** * ** * ********* *
10 **********************************************************************
0....5....1....1....2....2....3....3....4....4....5....5....6....6....7..
0 5 0 5 0 5 0 5 0 5 0 5 0
CPU% per hour (last 72 hours)
* = maximum CPU% # = average CPU%

show process cpu | ex 0.00%
CPU utilization for five seconds: 2%/0%; one minute: 2%; five minutes: 2%
PID Runtime(ms) Invoked uSecs 5Sec 1Min 5Min TTY Process
29 104385548 1257159864 83 0.07% 0.06% 0.07% 0 IPC Seat Manager
222 501004908 2195238060 228 0.15% 0.12% 0.13% 0 IP Input
257 455916 406552788 1 0.07% 0.07% 0.07% 0 Ethernet Msec Ti
302 62107292 151494934 409 0.07% 0.04% 0.03% 0 XDR mcast
381 85034184 104966716 810 0.07% 0.06% 0.05% 0 HIDDEN VLAN Proc
488 273475728 879094690 311 0.79% 0.43% 0.41% 0 Port manager per
553 15825156 1238748654 12 0.07% 0.07% 0.07% 0 PIM Process
568 15234756 513783806 29 0.07% 0.05% 0.05% 0 IP SLA Responder
569 500780 421085350 1 0.15% 0.09% 0.08% 0 IP SLAs Event Pr
582 106746360 3134180305 34 0.15% 0.14% 0.15% 0 OSPF-1 Hello

[balaji.bandi]

Thank you for the information, as per the output i do not see a major issue here, as asked other mates here..do you see a performance issue?

even though the link terminated 1GB link, what is the real bandwidth assured from a provider ?

If you NMS, do you see any time the traffic bursting more than expected?

Reset the interface counters and observe again how frequently they increase, ?

If this is your high outgoing interface some time i see and it was expected, as long as no performance effecting, or any users have issue, or any application performance issue, ( i believe you can ignore it).

[Joseph W. Doherty]

Often output drops are due to microbursts.

Considering your number of drops vs. outputted packets, why are you concerned?

[Georg Pauwen]

Hello,

your output drops are 0.0015 percent of total output packets. Are users or applications experiencing any noticeable problems ?