Troubleshooting High Cpu Utilization On Cisco Switches
The intervals are shown in the output for the show processes cpu history command. Knowing the time spent at interrupt is critical for determining the cause of CPU utilization. A capacity issue is one of the symptoms of high CPU utilization on Cisco IOS routers. These are examples of operations that have the potential to cause high CPU utilization: Spanning Tree IP Routing Table Updates Cisco IOS Commands Other Events Causing High CPU Utilization Spanning Tree this contact form
Then, the supervisor engine sends only a small number of packets, a maximum of 10 pps, to the MSFC for drop. What are the benefits of an oral exam? Switch#show platform cpu packet statistics !--- Output suppressed. Port 15/1 is the supervisor engine connection to the MSFC.
Troubleshooting High Cpu Utilization On Cisco Switches
In this case, a packet is routed through the same interface, which leads to the issue of an ICMP redirect for each packet. The CPU utilization history shows when the CPU is consistently receiving network packets, but it does not show the cause. Note:Total CPU utilization should not be used as a measure of the ability of the router to switch more packets. Disable console logging on the router with the no form of the logging console command.
While the switch might appear to operate fine at this CPU utilization level, when the switch CPU sustains a 50 percent utilization, its ability to react to dynamic network events is Is there excessive management traffic, such as SNMP polling, on the switch? Here is an example on an RP console: Router#monitor session 1 source interface fast 3/3 !--- Use any interface that is administratively shut down. Ip Input High Cpu Gig2/0/20 is where there is a traffic generator that pumps ARP traffic.
The two basic types of multicast distribution trees are source trees and shared trees. Fed Process Cisco Access—The access template maximizes system resources for access control lists (ACLs) to accommodate a large number of ACLs. For more information about switching paths in Cisco IOS Software, refer to the Configuring Switching Paths document. show system internal
cpu-queue rxq 0..31 field field offset offset Now you must link things together. Cisco Show Memory Usage Check CoPP and HWRL to see if there are drops for certain traffic/packets. End with CNTL/Z. With Cisco IOS-XE, Cisco has moved to a Linux kernel and all of the subsystems have been broken down into processes.
Fed Process Cisco
One CPU is the supervisor engine CPU, which is called the Network Management Processor (NMP) or the Switch Processor (SP). In this command output, notice that the top process is the Cat4k Mgmt LoPri : Switch#show processes cpu CPU utilization for five seconds: 96%/0%; one minute: 76%; five minutes: 68% PID Troubleshooting High Cpu Utilization On Cisco Switches Issue the show platform tcam utilization command to see how much TCAM has now been utilized and how much is available. Cisco Router High Cpu Interrupts This is normal.
Components Used The information in this document is based on Catalyst 3750 Switches. weblink The first packet for this destination (or flow - depends on the type of fast switching configured) will be processed. The switch typically receives SNMP queries at regular intervals, and the SNMP Engine system process consumes CPU resources handling the queries. In order to resolve the high CPU utilization issue, enable route summarization. How To Check Bandwidth Utilization On Cisco Router
Non-RPF Multicast Traffic Multicast routing (unlike unicast routing) is only concerned with the source of a given multicast data stream. A quick way to determine the cause of high CPU usage is to use the show system internal processes cpu command. The 16 queues allow the Catalyst 4500 to queue the packets on the basis of the packet type or priority. navigate here The first line of output from the show processes cpu command displays the percentages of the CPU cycles.
You can expect high CPU utilization for short durations because of the BGP Scanner process on a router that carries a large Internet routing table. Hulc Led Process High Cpu OAL uses an optimized routine to send information to the MSFC3 in order to generate the logging messages. Any examples, command display output, and figures included in the document are shown for illustrative purposes only.
These scenarios require the switching ASICs to send packets to the CPU for processing: Packets that are copied to the CPU, but the original packets are switched in hardware An example
TagMan-RecreateMtegR 1.00 0.00 10 0 100 500 0 0 0 0:00 K2CpuMan Review 30.00 37.62 30 53 100 500 41 33 1 2:12 K2AccelPacketMan: Tx 10.00 4.95 20 0 100 500 See Catalyst 3750 Series Switches High CPU Utilization Troubleshooting. Step 4: Use FED Tracing The only drawback with the method discussed in the last section is that it only dumps the last packet that goes into the sink, and it Troubleshoot High Cpu Usage Linux A rapidly incrementing packet type indicates that packet type is flooding the IP stack.
In this output, the total CPU utilization is 57 percent and the interrupt CPU utilization is 48 percent. As the console is interrupt-driven, each character is an interrupt. Background Information Before you look at the CPU packet-handling architecture and troubleshoot high CPU utilization, you must understand the different ways in which hardware-based forwarding switches and Cisco IOS Software-based routers his comment is here When traffic to the CPU is triggering high CPU usage, you often see that Netstack and its respective process are running high.
There is no impact on performance of the switch, with or without ACLs in the forwarding path. SNMP polling activities, particularly MIB walk—the Cisco IOS SNMP engine executes SNMP requests. This is especially likely to be the cause if there have not been recent changes to the network. Because the switch hardware sees the CPU receive-queue dropped packets as sent to the supervisor, the dropped packets are called Supervisor TxQueue Drop Statistics in the command output.
This is commonly seen when the CPU is interrupted due to ARP packets. Tom's IT Pro>Networking>Networking Sponsored> Diagnosing Hardware Issues Using Cisco IOS Commands Troubleshooting And Maintaining Cisco IP Networks (TSHOOT) By Amir RanjbarApril 8, 2015 11:11 AM Next Previous 4. When the debugging session is over, the debug messages are in the system log. A resolution of the root cause of that problem can be necessary in order to lower the CPU utilization.
You can use the output of the show processes cpu history privileged EXEC command to determine normal operating baseline utilization for the previous 72 hours. In the output, for CPU utilization for five seconds, the second number is the interrupt percentage. System Processes and Punted Packets On a Layer 3 switch, when the IP route is not known, the switch hardware punts (sends) IP packets to the CPU for IP routing. The packets routed through this tunnel must be switched through software.
Identifying TCAM Utilization Issues On a Layer 3 switch, the hardware uses the TCAM to contain the IP routing database. However, the next process in this sorted list is the “Check heaps” process, which has consumed only 0.78 percent of the total available CPU time over the last minute and the High CPU Utilization due to Fragmentation Reassemblies can drive up the CPU very high if the CPU has to reassemble a large number of packets. Tip:Be sure that you do not configure IP phone ports as trunk ports.
The write memory privileged EXEC command (particularly if the switch is in a stack). If the CPU is busy 5% of the time then the CPU is idle the other 95% of the time. A sample debugging session of IP packets is provided in Troubleshooting High CPU Utilization in the IP Input Process. Aggregate traffic from multiple modules can still burden the CPU heavily.
This is a sample output of the show processes cpu command when the CPU utilization is high due to the IGMP snooping process: switch#show processes cpu CPU utilization for five seconds:
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