【正文】 truncated清空和重置接口和計(jì)數(shù)器表93列出了你可以用來清空計(jì)數(shù)器和重置接口的特權(quán)模式clear命令。表93：接口清除命令Command Purpose clear counters [interfaceid]清除接口計(jì)數(shù)器clear interface interfaceid重置接口的硬件邏輯電路clear line [number | console 0 | vty number]在一個(gè)異步串行線路上重置接口邏輯電路為了清除用show interfaces特權(quán)模式命令顯示的接口計(jì)數(shù)，使用特權(quán)命令：(exec) clear counters從接口清除所有當(dāng)前接口計(jì)數(shù)，除非可選變量被指派來清除一個(gè)定接口類型，該特定接口來自于一個(gè)特定接口號的唯一接口號。注意：特權(quán)命令clear counters不能清除用SNMP重新收到的計(jì)數(shù)，只能清除用show interface特權(quán)命令顯示的計(jì)數(shù)。這個(gè)例子展示怎樣清除和重置千兆口0/5：Switch clear counters gigabitethernet0/5 Clear show interface counters on this interface [confirm] y Switch*Sep 30 08:42:55: %CLEAR5COUNTERS: Clear counter on interface GigabitEthernet0/5by vty1 ()清除和重置一個(gè)接口或一個(gè)串行線路，用命令：(interface) clear interface(interface) clear line在絕大多數(shù)環(huán)境中，你不必清除一個(gè)接口或串行線路的硬件邏輯電路。這個(gè)例子顯示怎樣清除和重置GBT接口0/5：Switch clear interface gigabitethernet0/5關(guān)閉和重啟接口關(guān)閉一個(gè)特定接口會禁用所有功能并且所有監(jiān)控命令顯示標(biāo)注這個(gè)接口不可用。通過動態(tài)路由協(xié)議給信息被發(fā)給其他的網(wǎng)絡(luò)服務(wù)服務(wù)設(shè)備。這個(gè)接口在所有路由更新中不被監(jiān)控。從特權(quán)模式開始，以下這些步驟關(guān)閉一個(gè)接口：Command Purpose Step1 configure terminal進(jìn)入全局配置模式Step2 interface {vlan vlanid} | {{fastethernet | gigabitethernet} interfaceid} | {portchannel portchannelnumber}選擇一個(gè)需被配置的端口Step3 shutdown關(guān)閉一個(gè)接口Step4 end返回特權(quán)模式　Step5 show runningconfig確認(rèn)你的條目重啟該接口用命令：(interface) no shutdown這個(gè)列子展示怎樣關(guān)閉千兆以太接口0/5：Switch configure terminalSwitch(config) interface gigabitethernet0/5 Switch(configif) shutdown Switch(configif)*Sep 30 08:33:47: %LINK5CHANGED: Interface GigabitEthernet0/5, changed state to a administratively down這個(gè)例子展示怎樣重啟千兆以太接口0/5：Switch configure terminalSwitch(config) interface gigabitethernet0/5 Switch(configif) no shutdown Switch(configif)*Sep 30 08:36:00: %LINK3UPDOWN: Interface GiogabitEthernet0/5, changed state to up為了確認(rèn)一個(gè)接口是禁用的，輸入命令：(interface) show interface在千兆以太接口0/1上，一個(gè)禁用的接口在show interface命令中被顯示為administratively down。Switch show interfaces output truncated GigabitEthernet0/2 is administratively down, line protocol is down Hardware is Gigabit Ethernet, address is (bia ) MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation ARPA, loopback not set Keepalive set (10 sec) Autoduplex, Autospeed output truncated配置一個(gè)三層接口帶有EMI的Catalyst3550交換機(jī)支持三種路由或橋接的三層接口：l SVIs：你應(yīng)該為任何你想路由流量的Vlan配置SVIs。當(dāng)你在interface vlan全局配置命令后輸入一個(gè)Vlan ID時(shí)，SVIs被創(chuàng)建。要刪除一個(gè)SVI，用命令：(global) no interface vlan需要關(guān)于指派二層端口到VLANs，請看“配置VLANs”。l 三層以太通道端口：以太通道由被路由端口組成。以太通道端口接口在“配置以太通道”中被描述。l 被路由端口：被路由端口是被用接口配置命令no switchport配置為三層的物理端口。注意：一個(gè)三層交換機(jī)可以有一個(gè)IP地址被指派個(gè)每個(gè)被路由端口和SVI。你可以配置的被路由和SVI接口在軟件上是沒有限制的；然而，因?yàn)橛布南拗?，這個(gè)數(shù)目和被配置的其他接口特征數(shù)目之間的相互關(guān)系會影響CPU的利用。需要更多的關(guān)于特征集的信息請看“為用戶選擇特性優(yōu)化系統(tǒng)資源”部分。所有三層接口要求一個(gè)IP地址來路由流量。以下的步驟展示怎樣配置一個(gè)三層接口和怎樣指派一個(gè)IP地址給接口。注意：如果該物理接口在二層模式（缺省），你必須用no switchport接口配置命令把接口放入三層模式。輸入一條no switchport命令會禁用并且重新啟用該接口，該設(shè)備可能會產(chǎn)生消息給直連接口。另外，當(dāng)你使用這條命令把接口放入三層模式，你正在刪除該端口的所有第二層特性。從特權(quán)模式開始，以下這些步驟配置一個(gè)三層接口：Command Purpose Step1 configure terminal進(jìn)入全局配置模式　Step2 interface {{fastethernet | gigabitethernet} interfaceid} | {vlan vlanid} | {portchannel portchannelnumber}進(jìn)入接口配置模式，而且要進(jìn)入一個(gè)將作為一個(gè)三層接口被配置的接口Step3 no switchport使物理接口進(jìn)入三層模式　Step4 ip address ip_address subnet_mask 配置IP地址和子網(wǎng)掩碼　Step5 no shutdown啟用該接口　Step6 end返回特權(quán)模式　Step7 show interfaces [interfaceid]show ip interface [interfaceid]show runningconfig interface [interfaceid]確認(rèn)配置　Step8 copy runningconfig startupconfig(可選) 把你的條目保存到配置文件要移除一個(gè)接口的IP地址，用命令：(interface) no ip address這個(gè)例子顯示怎樣配置一個(gè)接口作為一個(gè)被路端口并給他指派IP地址：Switch configure terminalEnter configuration mands, one per line. End with CNTL/Z.Switch(config) interface gigabitethernet0/2Switch(configif) no switchportSwitch(configif) ip address Switch(configif) no shutdownSwitch(configif) end 這是一個(gè)來自于一個(gè)接口的show interfaces特權(quán)命令的例子：Switch(config) show interfaces gigabitethernet0/2GigabitEthernet0/2 is up, line protocol is up Hardware is Gigabit Ethernet, address is (bia ) Internet address is MTU 1500 bytes, BW 100000 Kbit, DLY 10 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation ARPA, loopback not set Keepalive set (10 sec) Fullduplex, 100Mb/s input flowcontrol is off, output flowcontrol is off ARP type: ARPA, ARP Timeout 04:00:00 Last input 00:00:02, output 00:00:08, output hang never Last clearing of show interface counters never Queueing strategy: fifo Output queue 0/40, 0 drops。 input queue 0/75, 0 drops 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 89604 packets input, 8480109 bytes, 0 no buffer Received 81848 broadcasts, 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored 0 input packets with dribble condition detected 60665 packets output, 6029820 bytes, 0 underruns 0 output errors, 0 collisions, 16 interface resets 0 babbles, 0 late collision, 0 deferred 0 lost carrier, 0 no carrier 0 output buffer failures, 0 output buffers swapped out 這是一個(gè)來自于一個(gè)接口的show ip interfaces特權(quán)命令的例子：Switch show ip interface gigabitethernet0/2GigabitEthernet0/2 is up, line protocol is up Internet address is Broadcast address is Address determined by setup mand MTU is 1500 bytes Helper address is not set Directed broadcast forwarding is disabled Multicast reserved groups joined: Outgoing access list is not set Inbound access list is not set Proxy ARP is enabled Local Proxy ARP is disabled Security level is default Split horizon is enabled ICMP redirects are always sent ICMP unreachables are always sent ICMP mask replies are never sent IP fast switching is enabled IP fast switching on the same interface is disabled IP Flow switching is disabled IP CEF switching is enabled IP CEF Fast switching turbo vector IP multicast fast