A.during high traffic periods
B.after broken links are re-established
C.when upper-layer protocols require high reliability
D.in an improperly implemented redundant topology
E.when a dual ring topology is in use

A.TFTP server, Flash, NVRAM
B.ROM, NVRAM, TFTP server
C.NVRAM, TFTP server, ROM
D.Flash, TFTP server, ROM
E.Flash, NVRAM, ROM

A.a primary route,stored in the routing table
B.a backup route,stored in the routing table
C.a backup route,stored in the topology table
D.a primary route,stored in the topology table

A.ATM
B.IDS
C.IOS
D.IOX
E.IPS
F.SDM

A.Filtering can occur based on Layer 3 information.
B.Broadcasts are eliminated.
C.Routers generally cost less than switches.
D.Broadcasts are not forwarded across the router.
E.Adding a router to the network decreases latency.

A.remote DLCI on the main interface
B.local DLCI on the main interface
C.local DLCI on the subinterface
D.remote DLCI on the subinterface

A.source ip address：192.168.15.5 destination port：21
B.source ip address：192.168.15.37 destination port：21
C.ssource ip address192.168.15.41 destination port：21
D.source ip address：192.168.15.36 destination port：23
E.source ip address：192.168.15.46 destination port：23
F.source ip address：192.168.15.49 destination port：23

A.The PC has connectivity with a local host.
B.The PC has connectivity with a Layer 3 device.
C.The PC has a default gateway correctly configured.
D.The PC has connectivity up to Layer 5 of the OSI model.
E.The PC has the TCP/IP protocol stack correctly installed.

A.Addresses are allocated after a negotiation between the server and the host to determine the length of the agreement.
B.Addresses are assigned for a fixed period of time.At the end of period,a newquest for an address must be made,and another address is then assigned.
C.Addresses are leased to host.A host will usually keep the same address by periodically contacting the DHCP sever to renew the lease.
D.Addresses are permanently assigned so that the host uses the same address at all times.

A.允許unrestricted訪問(wèn)到console或VTY口
B.用防火墻去限制外網(wǎng)的網(wǎng)絡(luò)設(shè)備訪問(wèn)
C.因?yàn)閿?shù)據(jù)被自動(dòng)加密，所以總是允許使用TELNET命令訪問(wèn)網(wǎng)絡(luò)設(shè)備的命令行
D.使用SSH或其他加密、認(rèn)證機(jī)制去訪問(wèn)設(shè)備的配置
E.為了避免丟失密碼，所以不對(duì)密碼進(jìn)行加密（明文）