【文章內(nèi)容簡(jiǎn)介】 slot 3IP ADDRESS MAC ADDRESS EXPIRE(M) TYPE INTERFACE VPNINSTANCE VLAN PVC 00005ec41602 I Eth3/0/0 00005ec41603 20 D3 Eth3/0/0Total:2 Dynamic:1 Static:0 Interface:1amp。 說(shuō)明：檢查ARP表項(xiàng)時(shí)，需要注意：l 普通物理口：只在接口板上有ARP表項(xiàng)，顯示時(shí)需要指定板號(hào)；l VLANIF邏輯接口：主控板和收到ARP報(bào)文的接口板上有ARP表項(xiàng)，其他接口板沒(méi)有；l Ethtrunk邏輯接口：主控板和Ethtrunk成員板上都有ARP表項(xiàng)。如果發(fā)現(xiàn)RouterA未學(xué)習(xí)到對(duì)端的ARP，進(jìn)入檢查ping報(bào)文是否下發(fā)到接口板。如果RouterA學(xué)習(xí)到了對(duì)端的ARP，進(jìn)入檢查VLANIF接口。2. 檢查ping報(bào)文是否下發(fā)到接口板在RouterA上執(zhí)行ping命令。RouterA ping c 1000 PING : 56 data bytes, press CTRL_C to break Request time out Request time out Request time out Request time out Request time out Request time out Request time out如果接口發(fā)送的報(bào)文過(guò)多，可先配置ACL。打開另外一個(gè)RouterA的Telnet，配置ACL指定顯示報(bào)文的目的地址為對(duì)端IP地址。[RouterA] acl 3000[RouterAacladv3000] rule permit ip destination 0打開調(diào)試開關(guān)，查看發(fā)送的IP報(bào)文RouterA debugging ip packet acl 3000RouterA terminal monitorInfo:Current terminal monitor is onRouterA terinal displayInfo:Current terminal debugging is on如果RouterA上顯示如下信息：* RouterA IP/8/debug_case: Sending, interface = OURSENDPKT, version = 4, headlen = 20, tos = 0, pktlen = 84, pktid = 0, offset = 0, ttl = 255, protocol = 1, checksum = 0, s = , d = prompt: Transfering the packet from slot 6 to slot 3 * RouterA IP/8/debug_case:Slot=3。 Sending, interface = Ethernet3/0/0, version = 4, headlen = 20, tos = 0, pktlen = 84, pktid = 0, offset = 0, ttl = 255, protocol = 1, checksum = 61859, s = , d = prompt: Sending the packet from local at Ethernet3/0/0 加粗的文字表明ping報(bào)文從主控板下發(fā)到接口板，并在接口板上發(fā)送。3. 檢查ARP報(bào)文收發(fā)是否正常如果ping報(bào)文下發(fā)到了接口板，請(qǐng)進(jìn)一步檢查ARP報(bào)文收發(fā)是否正常。在RouterA上運(yùn)行以下命令。RouterA debugging arp packetRouterA terminal monitorInfo:Current terminal monitor is on RouterA terminal displayInfo:Current terminal debugging is on如果正確收發(fā)了ARP報(bào)文，將輸出如下信息。* RouterA ARP/8/arp_send:Slot=5。Send an ARP Packet, operation : 1, sender_eth_addr : 00005ec41602,sender_ip_addr : , target_eth_addr : 000000000000, target_ip_addr : * RouterA ARP/8/arp_rcv:Slot=5。Receive an ARP Packet, operation : 2,sender_eth_addr : 00005ec41603, sender_ip_addr : , target_eth_addr : 00e0fc70824f, target_ip_addr : 正常能夠ping通的環(huán)境，請(qǐng)求和應(yīng)答報(bào)文都應(yīng)該顯示，如果配置環(huán)境有問(wèn)題，可能會(huì)只有請(qǐng)求而沒(méi)有應(yīng)答，或者請(qǐng)求報(bào)文和應(yīng)答報(bào)文都沒(méi)有。如果上層收發(fā)正常，執(zhí)行以下命令顯示是否鏈路層發(fā)送正常。RouterA debugging ethernet packet arp interface ethernet 3/0/0* RouterA ETH/8/eth_send:Slot=3。Send an Eth Packet, interface : Ethernet3/0/0, eth format: 0, length: 42, prototype: 0806 arp, src_eth_addr : 00005ec41602, dst_eth_addr : ffffffffffff * RouterA ETH/8/eth_rcv:Slot=3。Receive an Eth Packet, interface : Ethernet3/0/0, eth format: 0, length: 42, prototype: 0806 arp, src_eth_addr: 00005ec41603, dst_eth_addr: 00005ec41602以上信息表明鏈路層發(fā)送ARP請(qǐng)求報(bào)文正常，可用4. 檢查報(bào)文收發(fā)計(jì)數(shù)是否正確進(jìn)一步定位。4. 檢查報(bào)文收發(fā)計(jì)數(shù)是否正確在接口視圖下執(zhí)行display this interface命令，或執(zhí)行display interface interfacetype interfacenumber命令查看報(bào)文計(jì)數(shù)。對(duì)于ARP請(qǐng)求報(bào)文，請(qǐng)查看廣播報(bào)文收發(fā)情況；對(duì)于ARP應(yīng)答報(bào)文，請(qǐng)查看單播報(bào)文收發(fā)情況。如果出現(xiàn)以下情況，請(qǐng)記錄定位過(guò)程和顯示的調(diào)試信息以及接口計(jì)數(shù)，并聯(lián)系華為工程師。l 上層沒(méi)有發(fā)送、或沒(méi)有正確發(fā)送ARP請(qǐng)求或者應(yīng)答報(bào)文；l 上層正確發(fā)送了ARP請(qǐng)求或者應(yīng)答報(bào)文，但是鏈路層沒(méi)有發(fā)送或者發(fā)送錯(cuò)誤；l 上層正確發(fā)送了ARP請(qǐng)求或者應(yīng)答報(bào)文，鏈路層也收發(fā)正常，但是對(duì)應(yīng)接口沒(méi)有收發(fā)計(jì)數(shù)。5. 檢查VLANIF接口對(duì)于VLANIF邏輯口，需要同步更新主機(jī)路由?？梢詧?zhí)行display fib命令檢查FIB表是否已更新。對(duì)于普通物理接口和其他邏輯接口則不需要檢查。RouterA display fibDestination/Mask Nexthop Flag TimeStamp Interface Token [70] InLoop0 0x0 [70] InLoop0 0x0 [3232] InLoop0 0x0 [3232] Eth3/0/0 0x0 amp。 說(shuō)明：如果發(fā)現(xiàn)VLANIF邏輯口主控板的ARP表項(xiàng)與接口板的ARP表項(xiàng)不一致，或者ARP表項(xiàng)一致但是沒(méi)有更新主機(jī)路由，請(qǐng)收集信息并保存錯(cuò)誤現(xiàn)場(chǎng)，聯(lián)系華為工程師。6. 檢查ICMP報(bào)文收發(fā)是否正常如果ARP表項(xiàng)都正常，并且是VLANIF邏輯口的時(shí)候也正確更新了路由表，仍出現(xiàn)其他異常，可進(jìn)行下述操作。l 先在用戶視圖下執(zhí)行debugging ip packet acl aclnumber命令，檢查IP報(bào)文收發(fā)情況；l 然后使用命令debugging ip icmp [ verbose ]，收集更多的故障信息以定位問(wèn)題。 故障處理案例 源MAC為組播地址現(xiàn)象1. 網(wǎng)絡(luò)環(huán)境圖26 源MAC為組播的案例環(huán)境圖兩臺(tái)路由器RouterA，RouterB配置VLANIF邏輯口，分別以Untagged方式加入一個(gè)端口Eth3/0/0,配置IP地址，配置如下。 配置RouterA。RouterA systemview [RouterA] vlan 100[RouterAvlan100] interface vlanif 100[RouterAVlanif100] ip address 24[RouterAVlanif100] interface ethernet 3/0/0[RouterAEthernet3/0/0] portswitch[RouterAEthernet3/0/0] port default vlan 100 配置RouterB。RouterB systemview [RouterB] vlan 100[RouterBvlan100] interface vlanif 100[RouterBVlanif100] ip address 24[RouterBVlanif100] interface ethernet 3/0/0[RouterBEthernet3/0/0] portswitch[RouterBEthernet3/0/0] port default vlan 1002. 故障分析RouterA上ping ，組網(wǎng)環(huán)境并不復(fù)雜，推測(cè)是由于ARP學(xué)習(xí)引起，可先從查看ARP表項(xiàng)開始排查。在RouterA上執(zhí)行display arp命令查看ARP表項(xiàng)。RouterA display arp slot 3IP ADDRESS MAC ADDRESS EXPIRE(M) TYPE INTERFACE VPNINSTANCE VLAN PVC 01005ec41600 I Vlanif100 Total:1 Dynamic:0 Static:0 Interface:1 只能看到RouterA上的接口ARP表項(xiàng)。在RouterB上執(zhí)行display arp命令查看ARP表項(xiàng)。RouterB display arp slot 3IP ADDRESS MAC ADDRESS EXPIRE(M) TYPE INTERFACE VPNINSTANCE VLAN PVC 00005ec41601 I Vlanif100 Total:1 Dynamic:0 Static:0 Interface:1 也沒(méi)有對(duì)端的ARP表項(xiàng)，只有本端接口的ARP表項(xiàng)。從顯示結(jié)果可以看到，RouterA上ARP表項(xiàng)中的MAC地址為組播MAC地址（第二位為1），初步定位為MAC地址配置錯(cuò)誤導(dǎo)致ping不通。執(zhí)行debug命令，觀察發(fā)送的ARP報(bào)文，確認(rèn)本端MAC地址。RouterA debugging ether packet arp interface vlanif 100RouterA terminal monitorRouterA terminal displayRouterA reset arpRoute