Output drops on wan interface

10.03.2021 By Fenrikazahn

Need support for your remote team? Check out our new promo! IT issues often require a personalized solution. Why EE?

output drops on wan interface

Get Access. Log In. Web Dev. NET App Servers. We help IT Professionals succeed at work. Medium Priority. Last Modified: Our ISP says that they've configured their interface to full duplex. For some reason, when I configure the WAN interface to full duplex, the interface shuts down. When I set it to Auto, it configures itself to half duplex. The ISP's switch is a Ciena If I connect a laptop with our internet address and connect it to the Ciena, I can get full duplex.

Below is the configuration of our WAN interface. Any ideas why I can't set it to full duplex? Start Free Trial. View Solutions Only. Predrag Jovic. Distinguished Expert This award recognizes someone who has achieved high tech and professional accomplishments as an expert in a specific topic.

Commented: By default, if auto negotiation is turned off on one side, other side will be auto-configured as half duplex. Collisions and late collisions are result of duplex mismatch.Hardware is C6k Mb Most of the time, a routing protocol needs to know the speed of the interface so it can choose the best route. Loopbacks are an important part of troubleshooting; they are used to isolate the fault on and end-to-end circuit especially when the circuit is down. Keepalive set 10 sec Keepalives are used on the routers interfaces as hello mechanism to check the end to end connectivity to the other end.

Routers interface used this mechanism to check the interface status. If you have no keepalive command its means that inerface status check mechansim in disabled and router will not transmit any keepalive packet on the link.

The last part of the line defines the type of the media. You may see many different implementations of flow-control technologies at different levels of OSI model e.

output drops on wan interface

If the clock mode of the near end of a link does not match the clock mode of the far end, the line protocol does not come up. The active and passive clock status is determined during the auto negotiation process before the transmission link is established. Last input never, output never, output hang never Last input, output are the number of hours, minutes, and seconds since the last packet was successfully received or transmitted by the interface. Note: This counter is updated only when packets are process switchednot when packets are fast switched.

The clear counters command is used to reset interface statistics. Flushes is used to count Selective Packet Discard. SPD is a mechanism that quickly drops low priority packets when the CPU is overloaded in order to save some processing capacity for high priority packets.

The flushes counter in the show interface command output increments as part of selective packet discard SPDwhich implements a selective packet drop policy on the IP process queue of the router. Therefore, it applies to only process switched traffic. The purpose of SPD is to ensure that important control packets, such as routing updates and keepalives, are not dropped when the IP input queue is full.

When the size of the IP input queue is between the minimum and maximum thresholds, normal IP packets are dropped based on a certain drop probability.

These random drops are called SPD flushes. Total output drops is the number of packets dropped because the output queue is full. 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. For example, if a large amount of bursty traffic comes in on a gigabit interface and is switched out to a Mbps interface, this might cause output drops to increment on the Mbps interface.

This is because the output queue on that interface is overwhelmed by the excess traffic due to the speed mismatch between the inbound and outbound bandwidths. Queueing strategy: fifo First-in, first-out FIFO queuing is the default queuing strategy that applies to all interfaces with more than 2 Mbps, or, in other words, E1 size or greater interfaces.

With the FIFO Queuing strategy, packets are forwarded through the interface in the order that they are received. Bytes: Total number of bytes, including data and MAC encapsulation, in the error-free packets received by the system. No buffers: Number of received packets discarded because there was no buffer space in the main system. Compare with ignored count. Broadcast storms on Ethernet networks and bursts of noise on serial lines are often responsible for no input buffer events.

Received broadcasts multicasts Total number of broadcast or multicast packets received by the interface. For instance, any Ethernet packet that is less than 64 bytes is considered a runt. Giants: Number of packets that are discarded because they exceed the maximum packet size of the medium.

Whirlpool dryer thermostat and thermal fuse 279816

For example, any Ethernet packet that is greater than bytes is considered a giant. Other input-related errors can also cause the input errors count to be increased, and some datagrams may have more than one error; therefore, this sum may not balance with the sum of enumerated input error counts.

CRC: Cyclic redundancy checksum generated by the originating LAN station or far-end device does not match the checksum calculated from the data received. A high number of CRCs is usually the result of collisions or a station transmitting bad data.Starting with Junos OS Release Some of the causes for such a loss of traffic or a block in transmission of data packets include overloaded system conditions, profiles and policies that restrict the bandwidth or priority of traffic, network outages, or disruption with physical cable faults.

You can use a number of show commands to determine and analyze the statistical counters and metrics related to any traffic loss and take an appropriate corrective measure.

Troubleshooting Output Drops with Priority Queueing

The fields displayed in the output of the show commands help in diagnosing and debugging network performance and traffic-handling efficiency problems. The following show commands and associated fields applicable for dropped packets enable you to view and analyze some of the system parameters for errors or disruption in transmitted packets. Following are some of the show interfaces extensive input counters and their definitions.

Following are definitions for some of the output counters for show interfaces extensive :. Following are definitions for some of the Queue counters for show interfaces extensive both outbound and inbound. This includes CoS queue number and its associated user-configured forwarding class name, and is displayed on IQ2 interfaces.

Following are some of the show interfaces queue output fields and their definitions. On M and M routers and most T Series routers, just the total number of dropped packets is displayed.

Internet Troubleshooting - Pathping Packet Loss

Following are the fabric queue statistics for dropped traffic:. The following statistics are related to Packet Forwarding Engine local traffic for show pfe statistics traffic fpc :. The preceding commands represent only the main parameters that you can use to identify and monitor traffic drops or errors. Depending on your specific deployment scenario and network conditions, you might need to view the output of other relevant show commands to evaluate different factors that might be resulting in traffic transmission losses.

Help us improve your experience. Let us know what you think. Do you have time for a two-minute survey? Maybe Later. Errors — Sum of the incoming frame aborts and FCS errors. Framing errors — Number of packets received with an invalid frame checksum FCS. Runts — Number of frames received that are smaller than the runt threshold. Policed discards — Number of frames that the incoming packet match code discarded because they were not recognized or not of interest.

Usually, this field reports protocols that the Junos OS does not handle. L3 incompletes — Number of incoming packets discarded because they failed Layer 3 usually IPv4 sanity checks of the header. L3 incomplete errors can be ignored by configuring the ignore-l3-incompletes statement. L2 channel errors — Number of times the software did not find a valid logical interface for an incoming frame.

L2 mismatch timeouts — Number of malformed or short packets that caused the incoming packet handler to discard the frame as unreadable. If this value is ever nonzero, the PIC is probably malfunctioning. Carrier transitions — Number of times the interface has gone from down to up. This number does not normally increment quickly, increasing only when the cable is unplugged, the far-end system is powered down and then up, or another problem occurs.

Give me love e chords

Errors — Sum of the outgoing frame aborts and FCS errors. Collisions — Number of Ethernet collisions. If it is nonzero, there is a software bug. Aged packets — Number of packets that remained in shared packet SDRAM so long that the system automatically purged them.

The value in this field should never increment. If it does, it is most likely a software bug or possibly malfunctioning hardware. Queued packets — Number of queued packets. Transmitted packets — Number of transmitted packets.

La frazione di pratoianni nel comune di

Tail-dropped packets — Number of packets dropped because of tail drop.Need support for your remote team? Check out our new promo! IT issues often require a personalized solution. Why EE? Get Access. Log In. Web Dev. NET App Servers. We help IT Professionals succeed at work. Medium Priority. Last Modified: I have replaced my cable and still the same thing.

Any Ideas on what could be causing this? The rest of the interface stats look good. Start Free Trial. View Solution Only. Commented: This is likely a normal thing.

This means that you could have traffic bursts that attempt to push the full M outbound and packets get buffered. Once the buffer reaches the max, it has to drop packets. These dropped packets are output drops.

Author Commented: I do have a M circuit to the ISP. I wish my boss would spring for that. Anyways, my thoughts are still the same, but I'll move my focus one small hop backwards. If your internal interface on the router is operating at gig speed connecting to your switch, you have the opportunity for a mismatch in speed capabilities. Users on the inside are operating at gig and can burst traffic at gig speeds. Coming into the router this isn't an issue, but going out it is limited to M.

This can create the same scenario I described the first time where the buffers fill and packets could be dropped, but now it's the speed mismatch within the router, and not at the ISP side. There could certainly be other reasons, but this is the first that comes to mind. Top Expert This award recognizes someone who has achieved high tech and professional accomplishments as an expert in a specific topic.

Are you running QoS on your router? That was exactly the problem. The inside interface was at a gig, and the WAN interface was at I tested this by setting the inside interface to as well, and the drops stopped. I put it back at a gig after testing, I don't believe it was causing performance problems.

Not the solution you were looking for?This document provides tips on how to troubleshoot output drops that result from a priority queueing mechanism configuration on a router interface. Supports up to four levels of priority queues. A router can report output drops when any of these methods are configured, but there are important functional differences between the methods and the reason for drops in each case.

The information presented in this document was created from devices in a specific lab environment. All of the devices used in this document started with a cleared default configuration.

If you are working in a live network, ensure that you understand the potential impact of any command before you use it. If you are working in a live network, ensure that you understand the potential impact of any command before using it. In the event of congestion, if the traffic exceeds the configured bandwidth, then all the excess traffic is dropped.

In the event of congestion, policing is used to drop packets when the bandwidth is exceeded. These two mechanisms use a built-in policer to meter the traffic flows.

The purpose of the policer is to ensure that the other queues are serviced by the queueing scheduler.

output drops on wan interface

In the cisco original priority queueing feature, which uses the priority-group and priority-list commands, the scheduler always serviced the highest-priority queue first.

If there was always traffic in the high priority queue, the lower-priority queues were starved of bandwidth and packets going to non-priority queues. Priority queueing PQ is the cisco legacy priority queueing mechanism. As illustrated below, PQ supports up to four levels of queues: high, medium, normal, and low. Enabling priority queueing on an interface changes the Output queue display, as illustrated below. Before priority queueing the Ethernet interface is using a single output hold queue with the default queue size of 40 packets.

After enabling PQ the Ethernet interface now is using four priority queues with varying queue limits, as shown in the output below:. As the packets arrive at an interface, the priority queues on that interface are scanned for packets in a descending order of priority.

unable to set full duplex 100 on WAN interface

The high priority queue is scanned first, then the medium priority queue, and so on. The packet at the head of the highest priority queue is chosen for transmission. This procedure is repeated every time a packet is to be sent. Each queue is defined by a maximum length or by the maximum number of packets the queue can hold.

output drops on wan interface

When an arriving packet would cause the current queue depth to exceed the configured queue limit, the packet is dropped. Thus, as noted above, output drops with PQ typically are due to exceeding the queue limit and not to an internal policer, as is the typical case with LLQ. The priority-list list-number queue-limit command changes the size of a priority queue.

This section looks at the token bucket concept. A token bucket itself has no discard or priority policy. The token bucket metaphor works along the following lines:. Each token signifies permission for the source to send a certain number of bits into the network.This document provides the information you need to understand and troubleshoot output drops on ATM interfaces.

You can use the show interface command on any Cisco router interface to see several important values:. Input and output rate in bits per second and packets per second five minutes is the default period. In this output, an enhanced ATM port adapter PA-A3 has experienced 11, output queue drops since the counters were last cleared on week and one day ago:.

On an ATM interface, the output of the show interface atm command sometimes displays a large number of output queue drops. All types of router interfaces, from serial to Ethernet, may experience output queue drops.

This is due to the amount of traffic or the method in which the router switches packets from the ingress incoming interface to the egress exiting interface. For more information on document conventions, refer to the Cisco Technical Tips Conventions. On ATM interfaces, output drops can be interpreted as something other than buffer exhaustion for the interface.

ATM interfaces typically use ATM-layer traffic shaping to limit the maximum amount of bandwidth used by a virtual connection. If you present more traffic to the virtual circuit VC than it is configured to transmit, the ATM interface tries to store the packet until it can be scheduled for transmission. However, the interface may need to drop some packets.

This can particularly happen if you burst above the traffic-shaping parameters for a period of time longer than the virtual circuit is configured to handle.

Traffic shaping is often implemented as part of a traffic contract with the circuit provider. Each of these service categories supports a unique set of traffic parameters that may include peak cell rate PCRsustained cell rate SCRand maximum burst size MBS :. When you specify a peak cell rate, you can tell the ATM interface to shape the output rate and ensure that the bits per second rate for the VC does not exceed the maximum value.

Here is an example:. ATM interfaces are only capable of forwarding a limited amount of traffic. SCR is a long-term rate average. This includes both the five-byte ATM header and the cell payload. For more information on these limitations, refer to additional configuration documents on Traffic Management.This chapter presents general troubleshooting information and a discussion of tools and techniques for troubleshooting serial connections.

The chapter consists of the following sections:.

Es posible los la mites los pones ta autoayuda y superacian

The information presented in this document was created from devices in a specific lab environment. All of the devices used in this document started with a cleared default configuration. If you are working in a live network, ensure that you understand the potential impact of any command before using it. For more information on document conventions, see the Cisco Technical Tips Conventions. The output of the show interfaces serial EXEC command displays information specific to serial interfaces.

This section describes how to use the show interfaces serial command to diagnose serial line connectivity problems in a wide area network WAN environment. The following sections describe some of the important fields of the command output. Other fields shown in the display are described in detail in the section "Detailed Information on the show interfaces serial Command," later in this chapter.

You can identify five possible problem states in the interface status line of the show interfaces serial display see Figure :. Table : Serial Lines: show interfaces serial Status Line Conditions - This table shows the interface status conditions, possible problems associated with the conditions, and solutions to those problems.

For this reason, use debug commands only to troubleshoot specific problems or during troubleshooting sessions with Cisco technical support staff. Moreover, it is best to use debug commands during periods of low network traffic and fewer users.

Debugging during these periods decreases the likelihood that increased debug command processing overhead will affect system use. Output drops appear in the output of the show interfaces serial command see Figure when the system is attempting to hand off a packet to a transmit buffer but no buffers are available.

Table Serial Lines: Increasing Output Drops on Serial Link - This table outlines the possible problem that may cause this symptom and suggests solutions. For instance, if a link is known to be overused with no way to remedy the situationit is often preferable to drop packets than to hold them.

However, some protocols, such as DECnet and local-area transport are sensitive to dropped packets and accommodate retransmission poorly, if at all. Input drops appear in the output of the show interfaces serial EXEC command see Figure when too many packets from that interface are still being processed in the system.