The network command “matches” one or more interfaces on a router. For each interface,
the network command causes the router to do three things:
1 The router broadcasts or multicasts routing updates out an interface.
2 The router listens for incoming updates on that same interface.
3 The router, when sending an update, includes the subnet of that interface in the
routing update
五.考題的疑問 一些考題的疑問 31日考試，近日看題，有些地方不明白，希望大家能幫忙解答一 下，不勝感謝 1 you need to find out the IPX address on a series router,which command displays all routed protocols and the interfaces on which the protocol is enable ? A show protocols B show interfaces 應(yīng)該是A吧？B不能顯示all routed protocols吧。
2 in what which mode switch read first part of frame with destination address and send frame immediately? A cut-through B fragment-free C something-else 應(yīng)該是fast-forward，fragment-free 還要檢查前64字節(jié)的出錯(cuò)，不會(huì)"immediately"轉(zhuǎn)發(fā)，所以選C吧？
3. you telnets to a pc on a remote subnet,which MAC address willl be present in the ARP table when you issue the show arp command? A local router Ethernet port B destination host Ethernet port 沒有用過這個(gè)命令，假如沒有telnet，是不是就是local router Ethernet port啊？
4 consider Frame Relay multipoint subinterfaces.which is a valid statemant? A all the routers are required to the fukky meshed B all routers must be in the same subnet to forward routing updates and broadcasts C Multipoint is the default configration for Frame Relay subinterfaces 這題應(yīng)該是B吧。我看電子教材上說的是“multipoint is used if you want the router to forward broadcasts and routing updates that it receives.select this if routing routing IP and you want all routers in same subnet”
5 which of the following are ture about 3 of the OSI model ? A it uses broadcast address B it establishes network address 我看的testking選的是A。它的解釋是layer 3 does not establish addresses rather it uses the addresses to route information.可我覺得它不建立網(wǎng)絡(luò)地址又怎么能路由呢？
8 what is the purpose of DLCIs in Frame Relay ? A they identify the logcal circuit between a local router and a frame relay WAN switch B they determine the frame relay encapsulation type C they represent the keepalives used to maintain the PVC in an active state D they represent the physical address of the router atteched to a Frme Relay network 應(yīng)該是C吧？A好象應(yīng)該是在一對(duì)路由器之間而不是和交換機(jī)之間啊
9 You just entered the following command "routers(config)#line console 0 " which Operation is most likely to follow ? A create a passWord on the console terminal line B change from configuration mode to console privilege mode 好象都不對(duì)啊，A之前應(yīng)該有l(wèi)ogin啊，B的話，可是現(xiàn)在已經(jīng)在這個(gè)模式下了啊
標(biāo)準(zhǔn)答案，請(qǐng)trust me 1。選A 自己做實(shí)驗(yàn)可以證實(shí)選A 2。C 這個(gè)很簡單，樓主解釋正確 3。A 有沒有TELNET都是 LOCAL ETHERNET PORT 4。B 解釋正確 5。B 建立網(wǎng)絡(luò)地址 8。A C是LMI的性能 9。A 這個(gè)題出的有點(diǎn)SB 10。樓主解釋正確 11。CONNECT是連接的意思，不代表什么程序 TELNET是程序啊
六.tk中有關(guān)廣播地址的一道題 what is the broadcast address for this network 192.57.78.0/27. A.192.57.78.33 B 192.57.78.64 c 192.57.78.87 d 192.57.78.97 e 192.57.78.159 f 192.57.78.254 首先這是一個(gè)c類地址（default-subnet是/24 可以得到X=27-24=3(用于子網(wǎng)化），2^3-2=6個(gè)有效子網(wǎng) M=8-3=5(用雨主機(jī)地址的分配，每個(gè)子網(wǎng)能提供2^5-2＝30個(gè)有效主機(jī)地址 而且可知道：有效子網(wǎng)為： 32，64，96，128，160，192 故可知廣播地址為63，95，127，159，191，223
七.路由器相關(guān) 12.You telnet to a host on a remote network.which MAC address will be present in the ARP table when you issue the "show arp "command?
a.MAC address of the destination host Ethernet port b.MAC address of the local router ethernet port c.MAC address of the the destination router serial port d.MAC address of the local router serial port
標(biāo)準(zhǔn)答案：B 但（A）也有爭議。
我的問題是： 1、假如是遠(yuǎn)程主機(jī)之間的通信，那么應(yīng)該是對(duì)端的ROUTER的MAC地址呀？ （這個(gè)通信中到底有幾個(gè)路由器呢，show arp說明我當(dāng)前是在路由器上執(zhí)行的操作，哪么怎么會(huì)還顯示自己的MAC地址， “arp CACHE” 中不是僅顯示外部來訪網(wǎng)絡(luò)設(shè)備的條目嗎？假如是這樣又怎么會(huì)是 B ，自己本地路由的 E0 MAC ）
2、每個(gè)網(wǎng)絡(luò)設(shè)備應(yīng)該只有一個(gè)MAC地址吧？路由也不例外是吧？ （B 和 D，這兩項(xiàng)選頂中： D是不是根本就是一種障眼法呢？ 根本沒有“路由的MAC地址是 serial port 的MAC 地址的說法，可以說路由的MAC就應(yīng)該是路由的 Ethernet port 的MAC 地址，對(duì)嗎？
九.黃金綜合版上的一道題 359.a hosta in the sale department cant connect to the hostb in management department. choose the reason! routera(e0)-----------------------(e0)routerb 192.168.23.1 192.168.21.5
hosta hostb 192.168.23.2 192.168.21.2 255.255.240.0 255.255.255.240 A. the routerb inteface's ip addresss. B. hosta's bad ip address C.hostb's badd ip address D.bad broadcast address E.the routera interface's ip addresss. Answer:C 我怎么覺得ip都對(duì)呢？？？
