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Tài liệu Quản trị mang System management commands
System Management Commands I-493System Management CommandsThis chapter describes the commands used to manage the system and its performance on thenetwork. In general, system or network management falls into the following categories. Thecommands that perform the tasks in these management categories are described in this chapterunless specified otherwise.•Configuration ManagementThe configuration of network routers determines how the network operates. To manage routerconfigurations, you need to list and compare configuration files on running routers, storeconfiguration files on network servers for shared access, and perform software installations andupgrades. (Configuration management commands required to perform these tasks are describedin the “System and Configuration File Load Commands” chapter in the ConfigurationFundamentals Command Reference.)Other configuration management tasks include naming the router, setting time services,configuring for synchronous logging of unsolicited messages and debug output, configuring arouter for weighted fair queueing, and configuring SNMP support. Configuration managementcommands required to perform these tasks are described in this chapter.•Fault ManagementTo manage network faults, you need to discover, isolate, and fix the problems. You can discoverproblems with the system’s monitoring commands, isolate problems with the system’s testcommands, and resolve problems with other commands, including debug.This chapter describes general fault management commands. For detailed troubleshootingprocedures and a variety of scenarios, see the Troubleshooting Internetworking Systemspublication. For complete details on all debug commands, see the Debug Command Reference.•System Performance ManagementTo manage system performance, you need to monitor and determine response time, error rates,and availability. Once these factors are determined, you can perform load-balancing and modifysystem parameters to enhance performance. For example, priority queuing allows you toprioritize traffic order. You can configure fast and autonomous switching to improve networkthroughput, as described in the “Configuring Interfaces” chapter of the ConfigurationFundamentals Configuration Guide.See the Internetwork Design Guide for additional information.For system management configuration tasks and examples, refer to the chapter entitled “Managingthe System” in the Configuration Fundamentals Configuration Guide. I-494 Configuration Fundamentals Command Referenceaccess-enableaccess-enableTo enable the router to create a temporary access list entry in a dynamic access list, use theaccess-enable EXEC command.access-enable [host][timeout minutes]Syntax DescriptionCommand ModeEXECUsage GuidelinesThis command first appeared in Cisco IOS Release 11.1.This command enables the lock-and-key access feature.You should always define either an idle timeout (with the timeout keyword in this command) or anabsolute timeout (with the timeout keyword in the access-list command). Otherwise, the temporaryaccess list entry will remain, even after the user has terminated his session.ExampleThe following example causes the software to create a temporary access list entry and tells thesoftware to enable access only for the host from which the Telnet session originated. If the accesslist entry is not accessed within 2 minutes, it is deleted.autocommand access-enable host timeout 2Related CommandsA dagger (†) indicates that the command is documented outside this chapter.access-list (extended)†autocommand†host (Optional) Tells the software to enable access only for the host from whichthe Telnet session originated. If not specified, the software allows all hostson the defined network to gain access. The dynamic access list contains thenetwork mask to use for enabling the new network.timeout minutes (Optional) Specifies an idle timeout for the temporary access list entry. Ifthe access list entry is not accessed within this period, it is automaticallydeleted and requires the user to authenticate again. The default is for theentries to remain permanently. It is recommended that this value equal theidle timeout set for the WAN connection. access-templateSystem Management Commands I-495access-templateTo manually place a temporary access list entry on a router to which you are connected, use theaccess-template EXEC command.access-template [access-list-number][dynamic-name][source][destination][timeout minutes]Syntax DescriptionCommand ModeEXECUsage GuidelinesThis command first appeared in Cisco IOS Release 11.1.This command provides a way to enable the lock-and-key access feature.You should always define either an idle timeout (with the timeout keyword in this command) or anabsolute timeout (with the timeout keyword in the access-list command). Otherwise, the dynamicaccess list will remain, even after the user has terminated the session.ExampleIn the following example, the software enables IP access on incoming packets in which the sourceaddress is 172.30.1.129 and the destination address is 172.16.52.12. All other source and destinationpairs are discarded.access-template 101 payroll host 172.30.1.129 host 172.16.52.12 timeout 2Related CommandsA dagger (†) indicates that the command is documented outside this chapter.access-list (extended)†autocommand†clear access-template†access-list-number Number of the dynamic access list.dynamic-name (Optional) Name of a dynamic access list.source (Optional) Source address in a dynamic access list. The keywords host andany are allowed. All other attributes are inherited from the originalaccess-list entry.destination (Optional) Destination address in a dynamic access list. The keywords hostand any are allowed. All other attributes are inherited from the originalaccess-list entry.timeout minutes (Optional) Specifies a maximum time limit for each entry within thisdynamic list. This is an absolute time, from creation, that an entry canreside in the list. The default is an infinite time limit and allows an entry toremain permanently. I-496 Configuration Fundamentals Command ReferencealiasaliasTo create a command alias, use the alias global configuration command. Use the no form of thiscommand to delete all aliases in a command mode or to delete a specific alias, and to revert to theoriginal command syntax.alias mode alias-name alias-command-lineno alias mode [alias-name]Syntax DescriptionDefaultsDefault aliases are in EXEC mode as follows:Command ModeGlobal configurationUsage GuidelinesThis command first appeared in Cisco IOS Release 10.3.You can use simple words or abbreviations as aliases. The aliases in the Default section arepredefined. They can be turned off using the no alias command.Table 61 shows the acceptable options for the mode argument in the alias global configurationcommand.mode Command mode of the original and alias commands. SeeTable 61 for a list of options for this argument.alias-name Command alias.alias-command-line Original command syntax.Command Alias Original Commandh helplo logoutp pingr resumes showw whereTable 61 Mode Argument OptionsArgument Options Modeconfiguration Global configurationcontroller Controller configurationexec EXEC aliasSystem Management Commands I-497See the summary of command modes in the “User Interface” chapter in the ConfigurationFundamentals Configuration Guide for more information about command modes.When you use online help, command aliases are indicated by an asterisk (*), as follows:Router#lo?*lo=logout lock login logoutWhen you use online help, aliases that contain spaces (for example, telnet device.cisco.com 25) aredisplayed as follows:Router# configure terminalEnter configuration commands, one per line. End with CNTL/Z.Router(config)# alias exec device-mail telnet device.cisco.com 25Router(config)# endRouter# device-mail?*device-mail=”telnet device.cisco.com 25"When you use online help, the alias is expanded and replaced with the original command, as shownin the following example with the td alias:Router(config)# alias exec td trace deviceRouter(config)# ^ZRouter# t?*td=”trace device” telnet terminal test tn3270traceTo list only commands and omit aliases,begin your input line with a space. In the following example,the alias td is not shown, because there is a space before the t? command line.Router# t?telnet terminal test tn3270 traceAs with commands, you can use online help to display the arguments and keywords that can followa command alias. In the following example, the alias td is created to represent the command teletdevice. The /debug and /line switches can be added to telnet device to modify the command:Router(config)# alias exec td telnet deviceRouter(config)# ^ZRouter# td ? /debug Enable telnet debugging mode /line Enable telnet line mode . whois Whois port <cr>Router# telnet devicehub Hub configurationinterface Interface configurationipx-router IPX router configurationline Line configurationmap-class Map class configurationmap-list Map list configurationroute-map Route map configurationrouter Router configurationTable 61 Mode Argument Options (Continued)Argument Options Mode I-498 Configuration Fundamentals Command ReferencealiasYou must enter the complete syntax for the alias command. Partial syntax for aliases are notaccepted. In the following example, the parser does not recognize the command t as indicating thealias td.bones# t% Ambiguous command: “t”ExampleIn the following example, the alias fixmyrt is created for the ip route198.92.116.16.alias exec fixmyrt clear ip route 198.92.116.16Related Commandshow aliases buckets-of-history-keptSystem Management Commands I-499buckets-of-history-keptTo set the number of history buckets that are kept during the response time reporter probe’s lifetime,use the buckets-of-history-kept response time reporter configuration command. Use the no form ofthis command to return to the default value.buckets-of-history-kept sizeno buckets-of-history-keptSyntax DescriptionDefault50 bucketsCommand ModeResponse time reporter configurationUsage GuidelinesThis command first appeared in Cisco IOS Release 11.2.A response time reporter probe can collect history and capture statistics. By default, history is notcollected. When a problem arises where history is useful (for example, a large number of timeoutsare occurring), you can configure the lives-of-history-kept response time reporter configurationcommand to collect history. You can optionally adjust the buckets-of-history-kept,filter-for-history, and sample-of-history-kept response time reporter configuration commands.When the number of buckets reaches the size specified, no further history for this life is stored.NoteCollecting history increases the RAM usage. Only collect history when you think there is aproblem. For general network response time information, use statistics.If history is collected, each bucket contains one or more history entries from the probe. When theprobe type is pathEcho, an entry is created for each hop along the path that the probe takes to reachits destination. The type of entry stored in the history table is controlled by the filter-for-historyresponse time reporter configuration command. The total number of entries stored in the historytable is controlled by the combination of samples-of-history-kept, buckets-of-history-kept, andlives-of-history-kept response time reporter configuration commands.Each time the probe starts a response time reporter operation, a new bucket is created until thenumber of history buckets matches the specified size or the probe’s lifetime expires. History bucketsdo not wrap. The probe’s lifetime is defined by the rtr schedule global configuration command. Theprobe starts a response time reporter operation based on the seconds specified by the frequencyresponse time reporter configuration command.size Number of history buckets kept during the response time reporterprobe’s lifetime. The default is 50 buckets. I-500 Configuration Fundamentals Command Referencebuckets-of-history-keptExampleIn the following example, probe 1 is configured to keep 25 history buckets during the probe’slifetime:rtr 1type echo protocol ipIcmpEcho 172.16.161.21buckets-of-history-kept 25lives-of-history-kept 1Related Commandsfilter-for-historylives-of-history-keptrtrrtr schedulesamples-of-history-kept buffersSystem Management Commands I-501buffersUse the buffers global configuration command to make adjustments to initial buffer pool settingsand to the limits at which temporary buffers are created and destroyed. Use the no form of thiscommand to return the buffers to their default size.buffers {small | middle | big | verybig | large | huge | type number} {permanent | max-free | min-free | initial} numberno buffers {small | middle | big | verybig | large | huge | type number}{permanent | max-free| min-free | initial} numberSyntax DescriptionDefaultThe default number of buffers in a pool is determined by the hardware configuration and can bedisplayed with the EXEC show buffers command.Command ModeGlobal configurationUsage GuidelinesThis command first appeared in Cisco IOS Release 10.0.small Buffer size of this public buffer pool is 104 bytes.middle Buffer size of this public buffer pool is 600 bytes.big Buffer size of this public buffer pool is 1524 bytes.verybig Buffer size of this public buffer pool is 4520 bytes.large Buffer size of this public buffer pool is 5024 bytes.huge Default buffer size of this public buffer pool is 18024 bytes. This value can beconfigured with the buffers huge size command.type number Interface type and interface number of the interface buffer pool. The type valuecannot be fddi.permanent Number of permanent buffers that the system tries to create and keep.Permanent buffers are normally not trimmed by the system.max-free Maximum number of free or unallocated buffers in a buffer pool.A maximum of 20,480 small buffers can be constructed in the pool.min-free Minimum number of free or unallocated buffers in a buffer pool.initial Number of additional temporary buffers that are to be allocated when thesystem is reloaded. This keyword can be used to ensure that the system hasnecessary buffers immediately after reloading in a high-traffic environment.number Number of buffers to be allocated. I-502 Configuration Fundamentals Command ReferencebuffersNormally you need not adjust these parameters; do so only after consulting with technical supportpersonnel. Improper settings can adversely impact system performance.You cannot configure FDDI buffers.Examples of Public Buffer Pool TuningIn the following example, the system will try to keep at least 50 small buffers free:buffers small min-free 50In the following example, the permanent buffer pool allocation for big buffers is increased to 200:buffers big permanent 200Example of Interface Buffer Pool TuningA general guideline is to display buffers with the show buffers command, observe which buffer poolis depleted, and increase that one.In the following example, the permanent Ethernet 0 interface buffer pool on a Cisco 4000 isincreased to 96 because the Ethernet 0 buffer pool is depleted:buffers ethernet 0 permanent 96Related Commandsbuffers huge sizeshow buffers [...]... technical support personnel The buffer size cannot be lowered below the default Example In the following example, the system will resize huge buffers to 20000 bytes: buffers huge size 20000 Related Commands buffers show buffers System Management Commands I-503 calendar set calendar set To set the system calendar for a Cisco 7000 series, Cisco 7200 series, or Cisco 4500 series, use the calendar set EXEC command... timer, and cdp run commands affect the operation of the IP on demand routing feature (that is, the router odr global configuration command) For more information on the router odr command, see the “IP Routing Protocols Commands chapter in the Network Protocols Command Reference, Part 1 Example In the following example, CDP is disabled: no cdp run Related Command cdp enable System Management Commands I-507... in Cisco IOS Release 10.0 The system internally keeps time in UTC, so this command is used only for display purposes and when the time is manually set Example In the following example, the timezone is set to Pacific Standard Time and is offset 8 hours behind UTC: clock timezone PST -8 Related Commands calendar set clock set clock summer-time show clock System Management Commands I-517 clock update-calendar... Router# show cdp traffic CDP counters: Packets output: 0, Input: 0 Hdr syntax: 0, Chksum error: 0, Encaps failed: 0 No memory: 0, Invalid packet: 0, Fragmented: 0 Related Commands clear cdp table show cdp traffic System Management Commands I-509 clear cdp table clear cdp table To clear the table that contains CDP information about neighbors, use the clear cdp table privileged EXEC command clear cdp... first appeared in Cisco IOS Release 11.2 Example In the following example, the logging buffer is cleared Router# clear logging Clear logging buffer [confirm] Router# Related Commands logging buffered show logging System Management Commands I-511 clock calendar-valid clock calendar-valid To configure the Cisco 7000 series or the Cisco 4500 as a time source for a network based on its calendar, use the clock... automatically read into the system clock However, you may use this command to manually read the calendar setting into the system clock This command is useful if the calendar set command has been used to change the setting of the calendar Example In the following example, the system clock is configured to set its date and time by the calendar setting: clock read-calendar Related Commands calendar set clock... is configured to set its date and time by the calendar setting: clock read-calendar Related Commands calendar set clock set clock update-calendar ntp update-calendar System Management Commands I-513 clock set clock set To manually set the system clock, use the clock set EXEC command clock set hh:mm:ss day month year clock set hh:mm:ss month day year Syntax Description hh:mm:ss Current time in hours (military... time The end time is relative to summer time If the starting month is after the ending month, the system assumes that you are in the Southern Hemisphere Examples In the following example, summer time starts on the first Sunday in April at 02:00 and ends on the last Sunday in October at 02:00: System Management Commands I-515 clock summer-time clock summer-time PDT recurring 1 Sunday April 2:00 last Sunday... Cisco 7200, or Cisco 4500 calendar, the system clock will be automatically set when the system is restarted or when the clock read-calendar EXEC command is issued The calendar maintains its accuracy, even after a power failure or system reboot has occurred The time specified in this command is relative to the configured time zone Example In the following example, the system calendar is manually set to 1:32... current status of the custom output queues Example In the following example, custom queue list number 3 is assigned to serial interface 0: interface serial 0 custom-queue-list 3 System Management Commands I-519 custom-queue-list Related Commands queue-list default queue-list interface queue-list protocol queue-list queue byte-count queue-list queue limit I-520 Configuration Fundamentals Command Reference . System Management Commands I-49 3System Management CommandsThis chapter describes the commands used to manage the system and its performance. discoverproblems with the system s monitoring commands, isolate problems with the system s testcommands, and resolve problems with other commands, including