A receiving host computes the checksum...

单项选择题A receiving host computes the checksum on a frame and determines that the frame is damaged.Theframe is then discarded.At which OSI layer did this happen?（）

A.session
B.network
C.physical
D.datalink
E.transport

点击查看答案

您可能感兴趣的试卷

你可能感兴趣的试题

1.多项选择题Which two statements are true regarding EIGRP？（）

A.Passive routes are in the process of being calculated by DUAL.
B.EIGRP supports VLSM，route summarization，and routing update authentication.
C.EIGRP exchanges full routing table information with neighboring routers with every update.
D.If the feasible successor has a higher advertised distance than the successor route，it becomes theprimary route.
E.A query process is used to discover a replacement for a failed route if a feasible successor is not identified from the current routing information.

点击查看答案

2.单项选择题Refer to the exibit. Three cisco 2950 switches are set to their default priority sttings.During the spanningtree process,which switch will be elected as the root bridge?（）

A.Switch3
B.Switch4
C.Switch2
D.Switch1

点击查看答案

3.单项选择题Given an IP address 172.16.28.252 with a subnet mask of 255.255.240.0, what is the correct network addres?（）

A.172.16.16.0
B.172.16.24.0
C.172.16.0.0
D.172.16.28.0

点击查看答案

4.单项选择题Which command can be used to verify the DLCI destination address in a Frame Relay static configuration?（）

A.show frame-relay end-to-end
B.show frame-relay map
C.show frame-relay lmi
D.show frame-relay pvc

点击查看答案

5.多项选择题As a frame leaves a Layer 3 device，the Layer 2 encapsulation information is changed from what it was when it entered the device. For what two reasons can this happen？（）

A.The data is moving from 10BASE-TX to 100BASE-TX.
B.The WAN encapsulation type has changed.
C.The data format has changed from analog to digital.
D.The source and destination hosts are in the same subnet.
E.The source and destination MAC addresses have changed.

点击查看答案

6.单项选择题Which layer 2 protocol encapsulation type supports synchronous and asynchronous circuis and has built-in security mechanisms?（）

A.Frame Relay
B.HDLC
C.x.25
D.PPP

点击查看答案

7.单项选择题What is the default administrative distance of OSPF？（）

A.120
B.100
C.90
D.110

点击查看答案

8.单项选择题A router has learned three possible routes that could be used to reach a destination network. One route is from EIGRP and has a composite metric of 20514560. Another route is from OSPF with a metric of 782.The last is from RIPv2 and has a metric of 4. Which route or routes will the router install in the routing table？（）

A. the OSPF route
B. the EIGRP route
C. the RIPv2 route
D. all three routes
E. the OSPF and RIPv2 routes

点击查看答案

9.单项选择题Which command sets and automatically encrypts the privileged enable mode password?（）

A.enbale password c1sco
B.secret enable c1sco
C.password enable c1sco
D.enable secret c1sco

点击查看答案

10.单项选择题Which address is the IPV6 all-RIP-routers muticast group address that is used by RIPng as the destaionaddress？（）

A.FF02：：A
B.FF05：：101
C.FF02：：9
D.FF02：：6

点击查看答案