Cisco total output drops incrementing. 2(55)SE8) problem is ...
Cisco total output drops incrementing. 2(55)SE8) problem is on every connected interfaces, some with ip phones others with PCs and uplink interface, everywhere total output drops are growing. Output drops occur when packets are dropped by the interface before they can be transmitted onto the network. I found problem about "Total output drops" in interface. #sh interfaces po5 Port-channel5 is up, line protocol is up (connected) Hardware is EtherChannel, address is 2c3e. The new interface also has output drops. Any idea what could be the issue? This just started happening, otherwise it had been stable. Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 44030950 There are no interface errors. Background Information Output drops on high-speed interfaces are an issue that can occur in any network environments, particularly when it deals with interfaces that support data transfer rates of 10 Gbps or higher. g Input queue: 0/2000/0/0 (size/max/drops/flushes); Total outp Looking at the Cisco docs on input & output queue drops, incrementing outbound queue size is not recommended as the packets are already on the router and it would be better to drop at input so TCP can throttle the app back. If you are consistently seeing output drops increment in combination with reaching the line speed of the interface your best option is to look into increasing the speed of that link. Troubleshooting Switch Port and Interface Problems: Total output drops - The number of packets dropped because the output queue is full. Given that this is normally an outcome to interface congestion the following steps explain the commands used to clarify the total interface usage in both terms of Mbits and overall utilization. Increasing queue-limit Increasing hold queue Infact following list of command can be very useful in troubleshooting output drops on interface – show interfaces switching show interfaces stats ip accounting mac-address show interfaces mac-accountin sh int <int no> | include drop Below is the output of “ show interface ” command Hi Team, I am seeing a total output drops are increasing in the switch side interface where the interface connected between router and switch. com Your input he I have 3850 switch running in version 16. I aleady check bandwidth it use in 70Mbps and out 340Mbps. OLD: i Hello, Facing an issue on ASR9k where I see increasing total input drops on a LACP bundle link . Please advice me how to In this Cisco Tech Talk, we walk you through how to troubleshoot output drops on Cisco Catalyst 9000 switches that use the Unified Access Data Plane (UADP) A Has anyone experience of the above switches? I have multiple stacks (no more than 5 switches in a stack) and seeing very high number of Output Errors on a lot of ports. If a large packet is received on a different interface and tries to egress here the packet may have to be fragmented. We have 2 switches, each with 3 Gig interfaces that are used as the VLAN for data replication between 3 nodes of an HA SAN (with gig nics). Is there a command where i can see the packet drops at a buffer level? Hi all, i just saw problem with increasing total output drops on interfaces at cat 2960s (WS-C2960S-48LPD-L ver. Know of something that needs documenting? Share a new document request to doc-ic-feedback@cisco. We also see output drops on the inside interface of our router at the same time this occurs. I started Speedtest on the PC and Total Output Drops started to increase rapidly on the switch port. GigabitEthernet0/0/2 is up, line protocol is up . Whether or not to be worried depends on the frequency of drops; in the "sh int" command you can use the packet count with this information to calculate the packet drop ratio. When the output drops happen we lose connectivity to the router and some I have started observing the Total Output Drops, on the MPLS link towards ISP, which are constantly incrementing. Input queue: 0/75/0/0 (size/max/drops/flushes); T otal output drops: 1988762 Queueing strategy: fifo Output queue: 0/40 (size/max) 5 minute input rate 202000 bits/sec, 61 packets/sec 5 minute output rate 245000 bits/sec, 68 packets/sec 500131403 packets input, 182892336075 bytes, 0 no buffer Received 424177 broadcasts (256028 multicasts) I have created a new VTI. 254 (Loopback3), destination 1 Hello, we are seeing high output drops on 1 interfaces on different switches. ( only 650Mbps Input). 07. conf t ! qo Hi, On a Cisco Catalyst 9200L switch, under the interface connected to a modern Access Point, I’m observing some packet drops as shown in the output below. 129/30 MTU 1500 bytes, BW 1544 K Capture the above output multiple times to see if the drops are incrementing at the rate at which the router is unable to fragment some packets. 1489) MTU 9000 bytes, BW 2000000 Kbit/sec, DLY 10 usec, reliability 255/255, txload 97/255, rxload Some discovery let us to find that the output drops on both the Multilink interface and the Policy map is incrementing continuously. What's strange, total output drops on such interfaces are almost the same - about 500000 packets after last cleaning. Capacity's port Gigabit. 130. It's important to check what configuration you have on one of the affected interfaces so we can verify the QoS configuration if there is any. What we have noticed is that we are seeing incrementing Output Drops on our serial interface in UK. For Layer 2 interfaces, "Total output drop" is caused by lack of port asic tx buffer, which impacts both hw and cpu switched traffic, most of the time due to oversubscription, or very high traffic rate Hi Everyone, 4500 device has config for GRE only. I cleared the counters but still it increasing high. In this sapn port I have connected a Cisco IPS 4260 Which can be the reason of this drops? Here is the output of the show int gi1/16 taken in an interval I've got a few Cisco 3650 switch stacks running IOS-XE 03. I see output drops incrementing. Jun 29, 2016 · Can someone explain to me the reasons for the "Total Output Drops" counter incrementing when there are no other output errors? I understand there can be drops from congestion and we are using class-based queuing. The link is barely in use by our traffic monitor, and these servers should cause a relatively low amount of traffic in general. 08E and I am seeing high Total Output Drops across pretty much all active interfaces. What things can I try to narrow down where the issues are coming fr Output drops indicate that your interface had become overwhelmed with outbound traffic. 1489 (bia 2c3e. Output Drop Totals Hi, In a SPAN port the “Total output drops:” increases and the output rate of the interface is about 50% of the capacity of the interface. Router Model: Cisco 3845 Switch Model : Cisco C3750 I recommend clearing the interface counters and then observing the number of drops over the next hour. Router#sh int gig 0/0 GigabitEthernet0/0 is up, line (queue depth/total drops/no-buffer drops/flowdrops) 0/45/0/45 (pkts output/bytes output) 2289867/2023749606 Fair-queue: per-flow queue limit 128 packets Maximum Number of Hashed Queues 2048 Now Class D has only 10% bandwidth from the 100MB ,as following : policy-map WAN-CoS class A priority percent 20 class B bandwidth percent 5 class C Can someone assist to identify the reasons for the "Total Output Drops" counter incrementing when there are no other output errors? This interface is SP facing interface which has 6 sub interfaces. Introduction We focused our investigation on Total Output Drops and on the fact that, between router and switch, there's 100Mbps in full Duplex. interface GigabitEthernet1/0/7 switchport access vlan 2 switchport mode access switchport voice vlan 201 srr-queue bandwidth share 10 10 60 20 queue-set 2 priority-queue out I have a 3750 switch that has a bunch of workstations plugged into it, I'm having an issue where alot of the ports have a good amount of output drops and I can't seem to figure out why. Ié Oô W [Ö [Ø \È ^X _ä Ÿ 7Ñ « " $ ©z& í( Wk* W , W». Question: Is it a common behavior for all the ports to drop packets like this, and could we tune any settings to reduce or prevent these drops? Good day, I am seeing some total output drops on a system on some ports and I’m wondering what it could mean? I see the number actively increasing as well. This document provides tips on how to troubleshoot output drops that result from a priority queueing mechanism configuration on a router interface. have You ever met this probl It means that 131 packets were dropped from the output queue. But I'm unable to identify from which sub interface the drops are occurring. ‰s MOBIè ýé2¥Ø ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ à3 Pÿÿÿÿÿÿÿÿ ÿÿÿÿÿÿÿÿÿÿÿÿ EXTH æ e Cisco Systems, Inc. So, instead of having HQRouter, I put a PC with a 100/1000Mbps NIC (Service Provider configured the same settings as with the HQRouter). I have got Speed 100, Duplex Full, and Bandwidth 100000 configured on the port. Solved: Hi all, Hope you can help me I have two interfaces having output drops and I really can't figure out why. 0 output buffer failures, 0 output buffers swapped out Most probably the cause of these drops are due to the fact that the traffic is comming from a higher bandwitdh interface to a lower bandwith one. This is all started yesterday when i up Troubleshooting Input Queue Drops and Output Queue Drops Interactive: This document offers customized analysis of your Cisco device. cfaa. This counter should only increment during heavy network traffic. Please assist. Is this correct? This 3850 switches are use only for end users (wired, Phones and wireless (no servers). The total number of output drops exactly match the output errors, e. . after a bit of research I come up with this configuration. 06. It starts increase again after i clear counters (Many interfaces of other devices are also reporting high discard rate in NMS) Introduction Output drops are a result of the traffic rate exceeding the maximum bandwidth specification of a given interface. (s Network is experiencing high totat output drops. I cleared the interface yeste Hi Guys, what would cause "Total output drops"? we have been seeing calls drops on ip phones. In this case you would most likely see this high traffic utilization on a graph. From a performance point I have a Cisco 2960 switch connected to a 4948E via port channel and I'm seeing output drops on the 2960 on the port channel. Pls find screenshot Serial0/0/1 is up, line protocol is up Hardware is GT96K Serial Internet address is 192. The old interface also had output drops which I attributed to an old 100M circuit. These ports are showing a large number of Total output drops in the show interface output. The output drops increment up by 200 - 700 every 15 minute interval during business hours. The Cisco Document Team has posted an article. Please help to advise me about this problem? Best Regards, Jackson Pls advise how to calculate the percent of Total Output Drops on this Layer2 interface (C9300-48T). This document describes how to troubleshoot output drops due to quality of service (QoS) on Cisco Catalyst Switches Series 2960, 3750, 3750G, 3750X, 3560. Match: any Queueing queue limit 64 packets (queue depth/total drops/no-buffer drops) 0/1941076/0 (pkts output/bytes output) 71644644/15290998941 bandwidth remaining 25% Exp-weight-constant: 9 (1/512) Mean queue depth: 0 packets class Transmitted Random drop Tail drop Minimum Maximum Mark pkts/bytes pkts/bytes pkts/bytes thresh thresh prob Hi Pereest23, The first thing is to check if the output drops increment in a certain time of the day, If it does, then we can think of the amount of traffic (bursty traffic) in a specific time. the buffer gets full quickly and the switch as to discard some packets. Hi Experts, We have a P2P link between India and UK. interface TenGigabitEthernet1/1/6 description floor 4 switchport trunk allowed vlan 11,12,14,15,30,999 switchpor Can someone assist to identify the reasons for the "Total Output Drops" counter incrementing when there are no other output errors? This interface is SP facing interface which has 6 sub interfaces. as shown below I'm looking for a way to know the root cause of these drops since the 20Gbps bunblde link is clearly under-utilized. The number of output queue drops should not exceed 100 in any given hour. g. While speedtest was running, I was talking to this phone and there were no voice issues. The other 5 in-use interfaces of the C3850 aren’t affected. 6. Though you shouldn't be seeing input drops in ideal circumstances the # of drops are minimal considering the volume of traffic received on the interface. After hours no drops are recorded. Solved: Dear Sir, One of my Catalyst 3750 switch have many out drops, I execute "sh mls qos int g2/0/3 statist" command, there are many output drops in queue3 threshold3. I have these switches in production for over a year Total output drops is the number of packets dropped because the output queue is full. most likely because of this. However, there is one commandthat could mitigate or even solve all of these issues in one go for the Cisco Catalyst 9K family of devices, including the Cisco Catalyst 9200, 9300, and 9500 that I have Feb 25, 2025 · This document describes how to troubleshoot output drops on the Catalyst 9000 series platforms. How do I troubleshoot this? I don't have support on this old 2921. Cisco has many documents on troubleshooting interface errors, e. 168. 02-07-2018 12:06 AM you could be overutilizing it , spiking the interface at times flooding the buffer causing drops to increment theres a specific Cisco tshoot doc for output drops on 3850s it may help you identify and fix the issue , but you have a bit of a bottleneck there too coming down to a 1gb from 4x1gbs and 20gb link behind it The Total Output Drops counter indicates saturation in the output queues of the affected interface. ggThis document describes how to troubleshoot output drops on the Catalyst 9000 series platforms. 20. I migrated from a 100M circuit to now 1G. And two different ports connected to different servers IPMIs has exactlly the same drops - 525598. I cleared the counters but drops are incrementing rapidly reliability 255/255, txload 1/255, rxload 1/255 Encapsulation TUNNEL, loopback not set Keepalive not set Tunnel source 192. 12. All the workstations are on 1Gb links and are very underutilized at about 6Mbs, so I know the drops aren't caused The most likely cause of a large output errors number is that you are overrunning the output queue. This condition can be exacerbated by mechanisms such as Quality of Service (QoS), which can selectively discard packets to manage congestion. In other words: there has been more traffic than the link could handle thus causing buffer overflow. A common cause of this might be traffic from a high bandwidth link being switched to a lower bandwidth link or traffic from multiple inbound links being switched to a single outbound link. When you do subsequent “show interface” commands are the output drops and output errors incrementing quickly? The last clearing of the show interface counters says never, so it’s hard to say whether this is a continuing problem or it was a one time issue that has cleared. We have put in service a catalyst 3850-12XS running ver 03. 8 and few interfaces having packet drops, like connections going to access points. 03E and we have noted that in certain ports, there is high output drops. . Auto QOS is configured on this switch and we have tried removing the qos config on the ports having problem but it didn't change anything. Am I correct in saying the interface below is dropping 27% of its packets? My calculation = Total output drops / (output packets + Total output drops) GigabitEthernet1/0/14 is up, line proto we have c3850 trunk with other switch 4948 and its LACP 4x1G interface bonding (etherchannel) out of 4 1G we are getting Total output drops on 2 interface. In tx direction you would see 'Total output drops' counter moving when hw or sw switched traffic is dropped due to lack of port asic tx buffers. Feb 23, 2017 · Its most likely the 3750 they have really low buffers and are renowned for total output drops incrementing , you don't get it in the newer switches they increased the buffer from 6mb to 12mb on 3ks The buffer is most likely filling and dropping especially when servers connected , these are really access switches there not built for server traffic but they do work fine with server too but you Apr 1, 2025 · Using wireshark for detailed understanding of output drops. Seeing output drops on the interfaces of your Cisco Catalyst switches and routers is never a good time and tracking down the root cause can be tricky. This are all gigabit interfaces, and no matter what I do those two interfaces that go to two access switches keep having output drops. Yes, these drops increment in bursts and then stay estable for a while, just as you say Below are output command show counter, show queueing, show module, show interface vlan 30 Intermittently we are seeing hundreds of thousands of output drops on 6 interfaces of a Cisco C3850 fiber switch that connects to edge Dell PowerConnect 2848 switches. On the 4948 where it is connected I don't see any input or output errors. GigabitEth I'd like some advice on an output drop issue I'm having with a point-to-point T1. The output you posted doesn't contain any clues to identify the cause of the input drops. This document describes how to troubleshoot output drops on high speed interfaces on the UADP ASIC based Catalyst 9000 series platforms. I am trying to determine if there is a problem with the ISP, because we have two sites 5 minute output rate 301000 bits/sec, 119 packets/sec 1) Is there anything else that can cause output drops besides the server nic not receiving the frames quickly enough? 2) What is the maximum number of output drops the interface counter can record? Does it rollover when it reaches the max? 3) What would be considered a healthy rate of output Aug 12, 2025 · This document describes how to troubleshoot output drops on high-speed interfaces on the UADP ASIC-based Catalyst 9000 series platforms. Output drops are caused by congested interfaces. Output errors are the number of frames not transmitted because the configured maximum number of collisions was exceeded. Could it be just because of the smaller buffer size on that switch. Traffic is at approx 50% up and 20% down so the drops shouldn't be from over utilization. leejmi, uuf7, gi0cf, xdj8, qz2m, fawv, fif8n, oipd, gurhv, ooeg4,