01-08-2015 02:56 PM - edited 03-07-2019 10:09 PM
Hi all,
We have a port on our Cisco 4500X switch (VSS) that is experiencing a lot of output drops. The port experiencing the output drops is the traffic leaving our data center to our headquarters via a 1Gbps Metro-E circuit. We're not experiencing high bandwidth utilization on the Metro 1Gbps circuit. Although we haven't clear the counters in a while, the output drops are continuing at a decent clip.
Any idea why there are so many output drops considering the bandwidth utilization doesn't reach 100%?
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Cisco IOS Software, IOS-XE Software, Catalyst 4500 L3 Switch Software (cat4500e-UNIVERSALK9-M)
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Te2/1/3 to_Metro_1Gbps_circuit routed full a-1000 1000BaseT
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IL1NP0001WAN#sh int ten2/1/3
TenGigabitEthernet2/1/3 is up, line protocol is up (connected)
Hardware is Ten Gigabit Ethernet Port, address is 0007.e3ff.fc17 (bia 0007.e3ff.fc17)
Description: to_Metro_1Gbps_circuit
Internet address is <IP address>
MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 9/255, rxload 2/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 1000Mb/s, link type is auto, media type is 1000BaseT
input flow-control is on, output flow-control is on
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:00, output never, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 2276092
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 8638000 bits/sec, 3735 packets/sec
5 minute output rate 35950000 bits/sec, 5540 packets/sec
L3 in Switched: ucast: 0 pkt, 0 bytes - mcast: 0 pkt, 0 bytes
L3 out Switched: ucast: 0 pkt, 0 bytes - mcast: 0 pkt, 0 bytes
IPv6 L3 in Switched: ucast: 0 pkt, 0 bytes - mcast: 0 pkt, 0 bytes
IPv6 L3 out Switched: ucast: 0 pkt, 0 bytes - mcast: 0 pkt, 0 bytes
62274823016 packets input, 22639883087683 bytes, 0 no buffer
Received 9302394 broadcasts (0 IP multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 input packets with dribble condition detected
110760882640 packets output, 109819304243187 bytes, 0 underruns
0 output errors, 0 collisions, 2 interface resets
0 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out
Thanks in advance.
Mike
01-08-2015 05:41 PM
Do you have QoS enabled?
01-08-2015 06:49 PM
Hello Leo,
No, it does not have QoS enabled on that particular switchport. But there is MQC QoS applied to a few other interfaces on the switch. It should just be using the FIFO queue, right?
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interface TenGigabitEthernet2/1/3
description to_Metro_1Gbps
no switchport
ip address <ip address> 255.255.255.248
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Thanks.
Mike
01-08-2015 09:09 PM
Either have traffic shaping or do QoS on the link.
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