The following equipment working on the data link layer of the OSI reference model is ______ .
- A . WAN switch
- B . Router
- C . Repeater
- D . Hub
Which of the following statements about fiber optics are wrong ? (Multiple Choice)
- A . Multimode fiber can transmit light with different wavelengths and different incident angles
- B . The core of multimode fiber is thinner
- C . When multimode fiber is used, the maximum transmission distance of the signal is longer than that of single mode fiber
- D . The cost of multimode fiber is lower than that of single mode fiber
The broadcast address of the natural classification network segment corresponding to the IP address 202.135.111.77 is _____________ .
The broadcast address of the natural classification network segment corresponding to the IP address 202.135.111.77 is _____________ .
During the establishment of the TCP connection as shown in the figure , the Z part of SYN should be filled in ________ .
- A . a
- B . b
- C . a+1
- D . b+1
D
Explanation:
X = a + 1 (confirm receipt of a , expect to send a + 1 next time )
Y = a + 1
Z = b + 1 (Confirm receipt b )
The default control protocol port used by FTP is ______ .
- A . 20
- B . 21
- C . 23
- D . 22
B
Explanation:
Use the ______ command to specify the operating system software to be used next time.
- A . startup
- B . boot-loader
- C . bootfile
- D . boot startup
B
Explanation:
boot- loader – load application file P192
Normally, the router will fragment packets longer than the interface MTU .
In order to detect the line MTU , you can ping the destination address with the ______ parameter .
- A . Ca
- B . Cd
- C . Cf
- D . Cc
C
Explanation:
-a ―――― With source
-f ――――- Do not allow fragmentation of ICMP Echo Request messages
-tos ―――- type of service tos field defaults to 0 ( 0-255 )
-t ――――- Message timeout time, default 2000 ms
-s ―――― Message size, default 56 bytes ( 20-8100 )
-c ―――― Number of packets, default 5
-h ―――― Specify the packet ttl value, the default is 255 ( 0-255 )
-m ―――― Specify the time interval for sending messages, the default is 200 milliseconds ( 1-65535 )
If a port running STP in the Ethernet switch does not receive or forward data, receives and sends BPDUs , and does not perform address learning, then the port should be in the ______ state.
- A . Blocking
- B . Listening
- C . Learning
- D . Forwarding
- E . Waiting
- F . Disable
B
Explanation:
In the switching network shown in the figure, all switches have enabled the STP protocol.
SWA was chosen as the root bridge. According to the information in the figure, the _______ port should be placed in the Blocking state. (Multiple choices)
- A . SWC ‘s P1
- B . SWC ‘s P2
- C . SWD of P1
- D . SWD ‘s P2
- E . Insufficient information to judge
BD
Explanation:
Bridge ID : Bridge priority. MAC address
4096 multiples maximum 65535 default 32768
Root Bridge Election: Line compares bridge priority, when comparing MAC addresses, the smaller the priority
The command to configure the bridge SWA bridge priority to 0 is ______ .
- A . [SWA] stp priority 0
- B . [SWA-Ethernet1/0/1] stp priority 0
- C . [SWA] stp root priority 0
- D . [SWA-Ethernet1/0/1] stp root priority 0
The IP address 10.0.10.32 and the mask 255.255.255.224 represent a ______ .
- A . Host address
- B . Network address
- C . Broadcast address
- D . None of the above
B
Explanation:
The IP address 10.0.10.32 and the mask 255.255.255.224 represent a ______ .
- A . Host address
- B . Network address
- C . Broadcast address
- D . None of the above
B
Explanation:
The IP address 10.0.10.32 and the mask 255.255.255.224 represent a ______ .
- A . Host address
- B . Network address
- C . Broadcast address
- D . None of the above
B
Explanation:
The subnet mask of the IP address 132.119.100.200 is 255.255.255.240 , so the broadcast address of the subnet where it is located is ______ .
- A . 132.119.100.207
- B . 132.119.100.255
- C . 132.119.100.193
- D . 132.119.100.223
A
Explanation:
The subnet mask of the IP address 132.119.100.200 is 255.255.255.240 , so the broadcast address of the subnet where it is located is ______ .
- A . 132.119.100.207
- B . 132.119.100.255
- C . 132.119.100.193
- D . 132.119.100.223
A
Explanation:
The subnet mask of the IP address 132.119.100.200 is 255.255.255.240 , so the broadcast address of the subnet where it is located is ______ .
- A . 132.119.100.207
- B . 132.119.100.255
- C . 132.119.100.193
- D . 132.119.100.223
A
Explanation:
The well-known port number of the transport layer used by TFTP is ______ .
- A . 67
- B . 68
- C . 69
- D . 53
C
Explanation:
TCP （ 6 ）：
ftp――20/21
ssh――22
telnet――23
smtp-25 receive mail
pop3-110 send mail
DNS――53
http―― 80
https-443 http security version, add ssl layer below
UDP(17) ：
DNS――53
Bootp――67 server / 68 client (that is dhcp , dhcp is developed based on bootp )
Tftp――69
Snmp――161 / 162 The server listens on port number 161 , the client listens on port number
In the Windows operating system, which command can display ARP entry information ?
- A . display arp
- B . arp Ca
- C . arp Cd
- D . show arp
B
Explanation:
arp -d delete arp entry
arp -s IP MAC-MAC static binding arp
The customer’s network connection looks like:
HostA—-GE0/0–MSR-1–S1/0—–WAN—–S1/0–MSR-2–GE0/0—-HostB
The two MSR routers are interconnected through the WAN, and the physical connection is now normal. MSR-1 interface S1 / 0 address 3.3.3.1/30 , the MSR-2 interface S1 / 0 address 3.3.3.2/30 , now MSR-1 on three static routes configured as follows:
ip route-static 192.168.1.0 255.255.255.0 3.3.3.2
ip route-static 192.168.2.0 255.255.255.0 3.3.3.2
ip route-static 192.168.0.0 255.255.255.0 3.3.3.2
The 192.168.0.0/22 subnet is the LAN segment where HostB is located.
So which of the following is correct ? (Multiple choice)
- A . All three routes will be written into the MSR-1 routing table
- B . Only the third route will be written to the MSR-1 routing table
- C . three routes can be a route 192.168.0.0 255.255.252.0 3.3.3.2 ip route-static instead of
- D . Only the first route will be written to the MSR-1 routing table
AC
Explanation:
The third note is that the mask is 24 bits and cannot replace the first two
Which of the following routing protocols only care about the distance and direction to the destination network segment ? (Multiple Choice)
- A . IGP
- B . OSPF
- C . RIPv1
- D . RIPv2
The two empty MSR routers are connected by the way shown in the figure. By configuring the IP address, the GE0 / 0 interfaces of the two routers can communicate with each other.
Now the following configurations are added to the two routers:
RTA:
[RTA]ospf
[RTA-ospf-1]area 0
[RTA-ospf-1-area-0.0.0.0]network 192.168.1.1 0.0.0.3
[RTA-GigabitEthernet0/0]ospf dr-priority 2
DAF:
[RTB]ospf [RTB-ospf-1]area 0
[RTB-ospf-1-area-0.0.0.0]network 192.168.1.1 0.0.0.3
[RTB-GigabitEthernet0/0]ospf dr-priority
Then after the OSPF neighbor state is stable, ______ .
- A . OSPF interfaces have the same priority, and no OSPF DR election is performed on the 192.168.1.0/30 network segment
- B . Of the two routers, one is DR and one is BDR
- C . Of the two routers, one is DR and the other is DRother
- D . The neighbor status of the two routers is FULL and 2-Way
B
Explanation:
[ Interface ] ospf dr-priority ( 0-255 ) modify the interface priority, the default is 1 , the non-participation election with priority 0 is only broadcast network, NBMA network only has DB , BDR election, Gigabit Ethernet default interface Broadcast modify ospf network type: [ interface ] ospf network-type () DR , BDR election is for the interface, network segment, not RT is DR , BDR . By comparing the interface priority (the bigger the better), the router id is the same (the bigger the better) the other DR2 status stays at 2-way
There is a default route in the router’s routing table, the destination network segment and mask are 0.0.0.0 , and the next hop is the router’s S0 / 0 interface, then the following description of this route is correct ______ . (Multiple choices)
- A . When the router receives a packet destined to the destination address 120.1.1.1 , if there is no other exact match in the router table, then the packet will match this default route
- B . The mask of this route is the shortest, so only when no other route matches the data packet, the data packet will be forwarded according to the default route.
- C . The metric of this route may be 3
- D . The priority of this route may be 100
ABCD
Explanation:
Static default route metric value is 0 , it is impossible protocol default metric route may be . 3 , Stub region:
Set stub rear region, to produce a three lsa default route, the default route metric similar import external routes RTD interface cost is set to 2 , the effect in question can reach
There is a default route in the router’s routing table, the destination network segment and mask are 0.0.0.0 , and the next hop is the router’s S0 / 0 interface, then the following description of this route is correct ______ . (Multiple choices)
- A . When the router receives a packet destined to the destination address 120.1.1.1 , if there is no other exact match in the router table, then the packet will match this default route
- B . The mask of this route is the shortest, so only when no other route matches the data packet, the data packet will be forwarded according to the default route.
- C . The metric of this route may be 3
- D . The priority of this route may be 100
ABCD
Explanation:
Static default route metric value is 0 , it is impossible protocol default metric route may be . 3 , Stub region:
Set stub rear region, to produce a three lsa default route, the default route metric similar import external routes RTD interface cost is set to 2 , the effect in question can reach
There is a default route in the router’s routing table, the destination network segment and mask are 0.0.0.0 , and the next hop is the router’s S0 / 0 interface, then the following description of this route is correct ______ . (Multiple choices)
- A . When the router receives a packet destined to the destination address 120.1.1.1 , if there is no other exact match in the router table, then the packet will match this default route
- B . The mask of this route is the shortest, so only when no other route matches the data packet, the data packet will be forwarded according to the default route.
- C . The metric of this route may be 3
- D . The priority of this route may be 100
ABCD
Explanation:
Static default route metric value is 0 , it is impossible protocol default metric route may be . 3 , Stub region:
Set stub rear region, to produce a three lsa default route, the default route metric similar import external routes RTD interface cost is set to 2 , the effect in question can reach
0.0.0/8 Static 60 0 100.1.1.1 GE0/0
At this time, the router receives a data packet with a destination address of 6.6.6.6 , then ______ .
- A . The packet will preferentially match the RIP route in the routing table because its mask is the longest
- B . The data packet will preferentially match the RIP route in the routing table because its priority is high
- C . The packet will preferentially match the static route in the routing table, because its cost Cost is small
- D . The packet will preferentially match the static route in the routing table because its mask is the shortest
A
Explanation:
Only the highest priority will be added to the routing table. Different masks will be added to the routing table. Routing table search rules 1 ) Longest match forwarding 2 ) Iterative search for non-directly connected network segments 3 ) Default route last match
An empty configuration MSR router RTA is connected to two routers RTB and RTC running in OSPF Area 0 through GE0 / 0 and GE1 / 0 respectively . RTA interface GE0 / 0 and GE1 / 0 of the IP addresses are 192.168.3.2/24 and 192.168.4.2/24 . Add the following configuration on RTA :
[MSR-ospf-1] area 0.0.0.0
[MSR-ospf-1-area-0.0.0.0]network 192.168.0 0.0.3.255
[MSR-GigabitEthernet0/0]ospf cost 2
[MSR-GigabitEthernet1/0]ospf dr-priority 0
Then the correct description about the above configuration is _____ . (Multiple choices)
- A . This configuration MSR router the GE0 / 0 , GE1 / 0 on both started OSPF
- B . This configuration only MSR router GE0 / 0 interface launched OSPF
- C . RTA may become the DR of the network segment where the two GE interfaces are located
- D . RTA can only become the DR of the network segment where one of the GE interfaces is located
- E . modify the interface GE0 / 0 of Cost does not affect the OSPF adjacency establishment of
BDE
Explanation:
[MSR-ospf-1-area -0.0.0.0] network 192.168.0 0.0.3.255 mask 22 , as described in the interface segment 0.0 , 1.0 , 2.0 , 3.0 Startup ospf G1 / 0 interface priority to 0 , The interface with priority 0 does not participate in DR , BDR election
The client router’s interface GigabitEthernet0 / 0 is connected to the LAN host HostA , and its IP address is 192.168.0.2/24 ;
Interface Serial6 / 0 interface is connected to the far end and is currently operating normally. The ACL configuration is now added as follows:
firewall enable
firewall default permit
acl number 3003
rule 0 permit tcp
rule 5 permit icmp
acl number 2003
rule 0 deny source 192.168.0.0 0.0.0.255
interface GigabitEthernet0/0
firewall packet-filter 3003 inbound
firewall packet-filter 2003 outbound
ip address 192.168.0.1 255.255.255.0
interface Serial6/0
link-protocol ppp
ip address 6.6.6.2 255.255.255.0
Assuming that other related configurations are correct, then ______ . (Multiple choices)
- A . HostA cannot ping the two interface addresses on the router
- B . HostA can not ping through 6.6.6.2 , but can ping through 192.168.0.1
- C . HostA can not ping through 192.168.0.1 , but can ping through 6.6.6.2
- D . HostA can Telnet to the router
CD
Explanation:
In fact, ACL is only limited by 2003 3003 , tcp icmp is allowed, meaningless by default
Note: the source address is rejected out 192.168.0.0/24 all packets, including icmp the echo , echo-Reply , etc. used in the G0 / 0 interface outbound direction, when Aping the gateway, the gateway returns icmp echo reply packets are deny If the G0 / 0 inbound direction, a of ping gateway, transmitted icmp echo packets are deny Ping 6.6.6.2 Similarly
In the network environment shown in the figure , perform the following NAT configuration on RTA :
[RTA]acl number 2000
[RTA-acl-basic-2000]rule 0 permit source 100.0.0.0 0.0.0.255
[RTA-acl-basic-2000]nat address-group 1 200.76.28.11 200.76.28.11
[RTA] interface Ethernet0 / 1
[RTA-Ethernet0/1]nat outbound 2000 address-group 1
After configuration, client_a and Client_B are accessing Server , at this time RTA ‘s NAT table may be ______ .
- A . Protocol GlobalAddr Port InsideAddr Port DestAddr Port
1 200.76.28.11 12289 100.0.0.1 1024 200.76.29.4 1024
VPN: 0 ， status: NOPAT， TTL: 00:01:00， Left:
00:00:59
1 200.76.28.11 12288 100.0.0.2 512 200.76.29.4 512
VPN: 0 ， status: 11， TTL: 00:01:00， Left:
00:00:51 - B . Protocol GlobalAddr Port InsideAddr Port DestAddr Port
1 200.76.28.11 12289 100.0.0.1 1024 200.76.29.4 1024
VPN: 0 ， status: 11， TTL: 00:01:00， Left:
00:00:59
1 200.76.28.12 12288 100.0.0.2 512 200.76.29.4 512
VPN: 0 ， status: 11， TTL: 00:01:00， Left:
00:00:51 - C . Protocol GlobalAddr Port InsideAddr Port DestAddr Port
1 200.76.28.12 12289 100.0.0.1 1024 200.76.29.4 1024
VPN: 0 ， status: 11， TTL: 00:01:00， Left:
00:00:59
1 200.76.28.11 12288 100.0.0.2 512 200.76.29.4 512
VPN: 0 ， status: 11， TTL: 00:01:00， Left: 00:00:51 - D . Protocol GlobalAddr Port InsideAddr Port DestAddr Port
1 200.76.28.11 12289 100.0.0.1 1024 200.76.29.4 1024
VPN: 0 ， status: 11， TTL: 00:01:00， Left:
00:00:59
1 200.76.28.11 12288 100.0.0.2 512 200.76.29.4 512
VPN: 0 ， status: 11， TTL: 00:01:00， Left:
00:00:51
D
Explanation:
Napt and only one address is allocated in the address pool
In the network environment shown in the figure, the two routers are connected back to back with serial ports. The speed of the interconnection link should be set to 2Mbps . The following statement is correct ______ .
- A . Need to determine the interface type and cable meet V.24 regulations
- B . Use the baudrate 2048000 command configuration on the RTA synchronization port
- C . Use the baudrate 2048000 command configuration on the RTB synchronization port
- D . Use the virtual-baudrate 2048000 command configuration on the RTB synchronization port
- E . In RTA using synchronous port bandrate 2048000 command configuration, RTB using synchronous port virtual-baudrate 2048000 command to configure
B
Explanation:
V . 24 Support same and asynchronous: asynchronous maximum rate 115200bps synchronous maximum rate 64000bps
V . 35 only supports synchronization: the highest rate is 2048000bps = 2Mbps
Configure bandwidth on DCE
DCE (Data Control Equipment) operator equipment, providing synchronous clock signal between DCE and DTE
DTE (Data Terminal Equipment) user equipment that accepts the clock signal provided by DCE
When configuring ISDN DCC , the customer configures the following dialer-rule on his MSR router :
[MSR] dialer-rule 1 acl 3000
So which of the following statements about this configuration are correct ? (Multiple Choice)
- A . Only packets matching ACL 3000 can trigger dialing
- B . Only packets matching ACL 3000 will be sent by the router through the dial-up link
- C . No permit or deny is defined , the configuration is incorrect
- D . The correct configuration should be: [MSR] dialer-rule 1 acl 3000 permit
Two empty-configured MSR routers RTA and RTB are interconnected back to back through their respective Serial1 / 0 interfaces. Make the following configurations on the two routers:
RTA: skip
[RouterA-Serial1/0] link-protocol fr ietf
[RouterA-Serial1/0] ip address 10.1.1.1 30
[RouterA-Seria11 / 0] fr map ip 10.1.1.2 30
RTB: [RouterB-Serial1/0] link-protocol fr ietf
[RouterB-Serial1/0] interface serial0/0.1
[RouterB-Serial1/0.1] ip address 10.1.1.2 30
[RouterB-Serial1/0.1] fr map ip 10.1.1.1 30
The physical link between the routers is good, so the following statement is correct ______ . (Multiple choices)
- A . two routers are not configured DLCI for , in RTA No ping through RTB
- B . In the RTA No ping through 10.1.1.2
- C . In the RTA on can ping through 10.1.1.2
- D . In the above configuration, if only the type of serial interface 0 / 0.1 on RTB is changed to P2MP , then 10.1.1.2 cannot be pinged on RTA
- E . In the above configuration, if only the type of serial interface 0 / 0.1 on RTB is changed to P2MP , then 10.1.1.2 can be pinged on RTA
The following description of the star network topology is correct ______ . (Multiple choices)
- A . Star topology is easy to maintain
- B . In a star topology, the failure of a certain line does not affect computer communication under other lines
- C . The star topology has high robustness, and there is no single point of failure. Central node failure
- D . Because the network with star topology is a shared bus bandwidth, when the network load is too heavy, it will cause performance degradation
AB
Explanation:
Hub connection bus type network shared bus bandwidth
The following description of the star network topology is wrong ______ . (Multiple choices)
- A . Star topology is easy to maintain
- B . In a star topology, the failure of a certain line does not affect computer communication under other lines
- C . The star topology has high robustness and there is no single point of failure
- D . Because the network with star topology is a shared bus bandwidth, when the network load is too heavy, it will cause performance degradation
The following description of circuit switching and packet switching is correct ______ . (Multiple choices)
- A . Small circuit switching delay and strong real-time transmission
- B . High utilization of circuit-switched network resources
- C . Large packet switching delay and poor real-time transmission
- D . Low packet utilization network resource utilization
AC
Explanation:
Circuit switching:
Advantages: small delay, transparent transmission
Disadvantages: fixed bandwidth, low network resource utilization
Packet switching:
Advantages: multiplexing, high network resource utilization
Disadvantages: large delay, poor real-time performance, and complex device functions
The following description of circuit switching and packet switching is correct ______ . (Multiple choices)
- A . Low utilization of packet-switched network resources
- B . Large packet switching delay and poor real-time transmission
- C . High utilization of circuit-switched network resources
- D . Small circuit-switching delay and strong real-time transmission
The network delay ( delay ) defines the time required for the network to transfer data from one network node to another network node. The network delay includes ______ . (Multiple choices)
- A . Propagation delay ( propagation delay )
- B . switching delay ( Switching Delay )
- C . Media access delay ( access delay )
- D . Queue delay ( queuing delay )
AB
Explanation:
Network delays include: propagation delay PD , exchange delay SD , media access delay AD , queue delay QD
The hub ( Hub ) works in the ______ of the OSI reference model .
- A . Physical layer
- B . Data link layer
- C . Network layer
- D . Transport layer
Which of the following layers does the TCP / IP protocol stack include ? (Multiple Choice)
- A . Network layer
- B . Transport layer
- C . Session layer
- D . Application layer
- E . Network interface layer
- F . Presentation layer
The device that realizes network interconnection on the network layer is ______ .
- A . Router
- B . Switch
- C . Hub
- D . Repeater
A
Explanation:
Routers and Layer 3 switches
In the Open System Interconnection Reference Model ( OSI ), ______ transmits data streams in the form of frames.
- A . Network layer
- B . Session layer
- C . Transport layer
- D . Data link layer
Which of the following advantages does the OSI reference model have ? (Multiple Choice)
- A . The OSI reference model provides compatibility and standard interfaces between devices and promotes standardization.
- B . The OSI reference model is a theoretical description of the information transmission process that occurs between network devices and defines how to implement each layer of function through hardware and software.
- C . An important feature of the OSI reference model is its layered architecture. The hierarchical design method can transform huge and complex problems into several smaller and easy-to-handle problems.
- D . The above statements are incorrect.
Which of the following advantages does the OSI reference model have ? (Multiple Choice)
- A . The OSI reference model provides compatibility and standard interfaces between devices and promotes standardization.
- B . An important characteristic of the OSI reference model is its layered architecture. The hierarchical design method can transform huge and complex problems into several smaller and easy-to-handle problems.
- C . The OSI reference model is a theoretical description of the information transmission process that occurs between network devices, and defines how to implement each layer of function through hardware and software.
- D . The above statements are incorrect.
The following statement about the functions of each layer of the OSI reference model is correct ______ . (Multiple choices)
- A . The physical layer involves the original bit stream transmitted on the communication channel ( Channel ), which defines the mechanical, electrical functions, and regulations required to transmit data.
- B . The network layer determines the best route for transmitting packets. The key issue is to determine how the data packets are routed from the source to the destination.
- C . The basic function of the transport layer is to establish and maintain virtual circuits, perform error checking and flow control.
- D . The session layer is responsible for data format processing and data encryption.
- E . The application layer is responsible for providing network services for applications.
Here on OSI statement reference functions of each model error is ______ .
- A . The physical layer involves the original bit stream transmitted on the communication channel ( Channel ), which defines the mechanical, electrical functions, and regulations required to transmit data.
- B . The network layer determines the best route for transmitting packets. The key issue is to determine how the data packets are routed from the source to the destination.
- C . The basic function of the transport layer is to establish and maintain virtual circuits, perform error checking and flow control.
- D . The session layer is responsible for data format processing and data encryption.
- E . The application layer is responsible for providing network services for applications.
D
Explanation:
The following statement about the functions of each layer of the OSI reference model is correct ______ . (Multiple choices)
- A . The session layer is responsible for data format processing and data encryption.
- B . The basic function of the transport layer is to establish and maintain virtual circuits, perform error checking and flow control.
- C . The network layer determines the best route for transmitting packets. The key issue is to determine how the data packets are routed from the source to the destination.
- D . The physical layer involves the original bit stream transmitted on the communication channel ( Channel ), which defines the mechanical, electrical functions, and regulations required to transmit data.
- E . The application layer is responsible for providing network services for applications.
The following statement about the OSI reference model is correct ______ .
- A . The data at the transport layer is called a frame ( Frame )
- B . The data at the network layer is called a segment .
- C . data link layer called packets ( Packet )
- D . The data in the physical layer is called bit ( Bit )
The main function of the physical layer of the OSI reference model is ______ .
- A . Physical address definition
- B . Establish an end-to-end connection
- C . Transmit bit stream between terminal equipment, define voltage, interface, cable standard and transmission distance etc.
- D . Transfer data from one end host to the other end host
The IP protocol corresponds to layer ______ of the OSI reference model .
- A . 5
- B . 3
- C . 2
- D . 1
B
Explanation:
Application layer protocol: see T13
Transport layer protocol: TCP (6) UDP (17)
Network layer protocols: IP , ICMP ( ICMP messages can be divided into ICMP error messages and ICMP query messages), IGMP (Internet Group Management Protocol, responsible for managing multicast groups)
Network interface layer protocols: Ethernet, Token Ring, HDLC , PPP , X.25 , Frame Relay, PSTN , ISDN, etc.
In the OSI reference model, the function of the network layer is mainly ______ .
- A . Transmit the original bit stream on the channel
- B . Make sure that the pieces of information that arrive at the other party are correct
- C . Determine how the data packets are routed from the source to the destination
- D . Strengthen the function of transmitting the original bit stream in the physical layer, and control the flow
Data segmentation is done in ______ in the OSI reference model .
- A . Physical layer
- B . Network layer
- C . Transport layer
- D . Access layer
The to-end reliable data transfer and flow control is the OSI reference model ______ .
- A . Presentation layer
- B . Network layer
- C . Transport layer
- D . Session layer
In the OSI reference model, encryption is a function of ______ .
- A . Physical layer
- B . Transport layer
- C . Session layer
- D . Presentation layer
TCP belongs to ______ of OSI reference model .
- A . Network layer
- B . Transport layer
- C . Session layer
- D . Presentation layer
UDP belongs to ______ of the OSI reference model .
- A . Network layer
- B . Transport layer
- C . Session layer
- D . Presentation layer
SPX belongs to ______ of the OSI reference model .
- A . Network layer
- B . Transport layer
- C . Session layer
- D . Presentation layer
B
Explanation:
There are transport layer protocols TCP / IP protocol suite is the TCP / the UDP , and IPX / SPX protocol suite SPX etc.
DNS works on the OSI reference model ______ .
- A . Network layer
- B . Transport layer
- C . Session layer
- D . Application layer
Connect two switches with an Ethernet cable, and the MDI type of the interconnection port is configured as across , then this Ethernet cable should be ________ .
- A . Only use crossover cables
- B . Only use direct-connect cables
- C . Both parallel and crossover cables can be used
- D . Neither parallel network cable nor cross network cable
A
Explanation:
Cross line of equipment on the same layer, straight lines on different layers
Ethernet switch interface type MDI / MDIX adaptive
MDI straight line
MDIX crossover
Here is set to MDI , only cross lines
The following statement about Ethernet is correct ________ . (Multiple choices)
- A . Ethernet is a network based on shared media
- B . Ethernet adopts CSMA / CD mechanism
- C . Ethernet transmission distance is short, the longest transmission distance is 500m
- D . The above statements are incorrect
AB
Explanation:
10BASE Ethernet transmission distance depends on the transmission medium
10BASE5 thick coaxial cable 500m
10BASE2 thin coaxial cable 200m (the coaxial cable is complicated to lay and inconvenient to use)
10BASE-T twisted pair UTP 100m (gradually becoming the Ethernet standard)
Five categories 150m
The standard physical medium for 53.100BASE-TX is ______ .
The following statement about CSMA / CD is correct ______ . (Multiple choices)
- A . CSMA / CD is used in bus-type Ethernet, mainly to solve the problem of how to detect conflicts and ensure the orderly transmission of data when multiple stations send data simultaneously.
- B . When a station connected to the Ethernet wants to transmit a frame, it must wait until the channel is idle, ie the carrier disappears.
- C . The station can only start transmitting its frames when the channel is idle.
- D . If two stations start transmitting at the same time, they will hear the collision of signals and suspend the transmission of frames.
Which of the following statements about MAC addresses are correct ? (Multiple Choice)
- A . Ethernet uses MAC address to identify the host
- B . MAC address is a logical address that is easy to change
- C . The MAC address is fixed in the ROM , usually cannot be changed
- D . Usually only the terminal host needs the MAC address, routers and other network devices do not need
AB
Explanation:
FLASH memory: store application program files, the configuration file IP address is in the operating system’s RAM (random access memory, used for random storage, such as the current configuration), and the MAC address is fixed in the network card ROM (read-only memory, which stores the BOOTROM program, for In the method of replying when the application or configuration file fails, the theory cannot be changed and is the only one in the world
48 -bit MAC : 24 -bit OUI (application, logo manufacturer) + 24 -bit EUI IP address hides the physical address from the upper layer, so that the internet shows a unified address format, but the actual communication ip address cannot be recognized by the physical network, and the physical network is still physical Address, so it is necessary for arp to parse out the MAC , that is, the data communication between devices must know the ip address and the MAC address
Which of the following statements about MAC addresses are wrong ? (Multiple Choice)
- A . Ethernet uses MAC address to identify the host
- B . MAC address is a logical address that is easy to change
- C . The MAC address is fixed in the ROM , usually cannot be changed
- D . Usually only the terminal host needs the MAC address, routers and other network devices do not need
Which of the following statements about fiber optics are correct ? (Multiple Choice)
- A . Multimode fiber can transmit light with different wavelengths and different incident angles
- B . The cost of multimode fiber is lower than that of single mode fiber
- C . When multimode fiber is used, the maximum transmission distance of the signal is longer than that of single mode fiber
- D . The core of multimode fiber is thinner
WLAN ( Wireless LAN ) is the product of the combination of computer network and wireless communication technology. Which of the following are WLAN technical standards ? (Multiple choice)
- A . 802.11a
- B . 802.11b
- C . 802.11c
- D . 802.11g
AB
Explanation:
Maximum transmission rate
WLAN ( Wireless LAN ) is the product of the combination of computer network and wireless communication technology. Which of the following are WLAN technical standards ? (Multiple choice)
- A . 802.11a
- B . 802.11b
- C . 802.11c
- D . 802.11g
AB
Explanation:
Maximum transmission rate
WLAN ( Wireless LAN ) is the product of the combination of computer network and wireless communication technology. Which of the following are WLAN technical standards ? (Multiple choice)
- A . 802.11a
- B . 802.11b
- C . 802.11c
- D . 802.11g
AB
Explanation:
Maximum transmission rate
WLAN ( Wireless LAN ) is the product of the combination of computer network and wireless communication technology. Which of the following are WLAN technical standards ? (Multiple choice)
- A . 802.11a
- B . 802.11b
- C . 802.11c
- D . 802.11g
AB
Explanation:
Maximum transmission rate
WLAN ( Wireless LAN ) is the product of the combination of computer network and wireless communication technology. Which of the following are WLAN technical standards ? (Multiple choice)
- A . 802.11a
- B . 802.11b
- C . 802.11c
- D . 802.11g
AB
Explanation:
Maximum transmission rate
WLAN ( Wireless LAN ) is the product of the combination of computer network and wireless communication technology. Which of the following are WLAN technical standards ? (Multiple choice)
- A . 802.11a
- B . 802.11b
- C . 802.11c
- D . 802.11g
AB
Explanation:
Maximum transmission rate
The 802.11b protocol defines 14 channels in the 2.4 GHz frequency band , and there is overlap in spectrum between adjacent channels.
In order to maximize the use of frequency band resources, which of the following channels can be used for wireless coverage ?
- A . 1 、 5 、 9
- B . 1 、 6 、 11
- C . 2 、 6 、 10
- D . 3 、 6 、 9
B
Explanation:
The difference between each pair should be ≥5
The 802.11b protocol defines 14 channels in the 2.4 GHz frequency band , and there is overlap in spectrum between adjacent channels. In order to maximize the use of frequency band resources, which of the following channels can be used for wireless coverage ?
- A . 1 、 5 、 9
- B . 1 、 6 、 10
- C . 2 、 7 、 12
- D . 3 、 6 、 9
C
Explanation:
The difference between each pair should be ≥5
There are many kinds of WAN interfaces. The following description of the WAN interface is wrong ______ .
The AV24 protocol interface can work in both asynchronous and asynchronous modes. In asynchronous mode, the link layer uses PPP encapsulation.
The BV35 protocol interface can work in both asynchronous and asynchronous modes. In asynchronous mode, the link layer uses PPP encapsulation.
C. BRI / PRI interface is used for ISDN access, the default link encapsulation is PPP
The DG703 interface provides high-speed data synchronization communication services.
Explanation:
V . 24 Support same and asynchronous: asynchronous maximum rate 115kps synchronous maximum rate 64kbps
V . 35 only supports synchronization: the highest rate is 2048000bps = 2Mbps
Two access methods of ISDN :
BRI interface → 2B + DB channel 64kbps D channel 16kbps
PRI interface → E1 30B + D
T1 23B+D
Default PPP encapsulation
There are many kinds of WAN interfaces. The following description of WAN interfaces is correct ______ . (Multiple choices)
The AV24 protocol interface can work in both asynchronous and asynchronous modes. In asynchronous mode, the link layer uses PPP encapsulation.
The BV35 protocol interface can work in both asynchronous and asynchronous modes. In asynchronous mode, the link layer uses PPP encapsulation.
C. BRI / PRI interface is used for ISDN access, the default link encapsulation is PPP
The DG703 interface provides high-speed data synchronization communication services.
For the understanding of packet switching mode, the correct one in the following statement is ______ . (Multiple choices)
- A . Packet switching is based on store and forward ( Store-and-Forward Switching exchange) of
- B . The transmitted information is divided into packets of a certain length and forwarded in units of packets
- C . Each packet carries the address identification of the receiver and the sender, the packet can be directly forwarded without any operation, thereby improving efficiency
- D . Packet switching includes frame-based packet switching and cell-based packet switching
ABD
Explanation:
Check the source and destination of each packet, re-operate, and forward the packets one by one, which increases the delay but the resource utilization rate is high. Although the line is monopolized by a group at a certain moment, the line bandwidth is multiplexed After the total utilization rate is high
For the understanding of packet switching mode, the correct one in the following statement is ______ . (Multiple choices)
- A . Packet switching is a switching method based on cut-through switching
- B . The transmitted information is divided into packets of a certain length and forwarded in units of packets
- C . Packet switching includes frame-based packet switching and cell-based packet switching
- D . Each packet carries the address identification of the receiver and the sender, the packet can be directly forwarded without any operation, thereby improving efficiency
A company that establishes a company network needs to connect to a wide area network. The bandwidth of the connection is required to be greater than 1Mbps . Which of the following interfaces and protocols are available ? (Multiple choice)
AV35 protocol interface and cable, using PPP as the link layer protocol
BV35 protocol interface and cable, using Frame Relay as the link layer protocol
C. PRI interface and cable, bundle multiple time slots, use PPP as the link layer protocol
D. BRI interface and cable, bundle multiple time slots, use PPP as the link layer protocol.
Explanation:
V . 24 Support same and asynchronous: asynchronous maximum rate 115kbps synchronous maximum rate 64kbps
V . 35 only supports synchronization: the highest rate is 2048000bps = 2Mbps
Two access methods of ISDN :
BRI interface → 2B + DB channel 64kbps D channel 16kbps maximum rate 144kbps
PRI interface → E1 30B + D maximum rate 2Mbps T1 23B + D maximum rate 1.544Mbps
The two routers of the customer are connected back to back through V.35 cable, and one of the routers has the following interface information: [MSR-Serial0 / 0] display interface Serial 0/0
Serial0/0 current state: UP
Line protocol current state: UP
Description: Serial6/0 Interface
The Maximum Transmit Unit is 1500 ， Hold timer is 10(sec)
Internet Address is 6.6.6.1/30 Primary
Link layer protocol is PPP
LCP opened ， IPCP opened
From the above information, you can know ______ . (Multiple choices)
- A . This router has completed PPP negotiation with the remote device and successfully established a PPP link
- B . The PPP PAP or CHAP authentication and verification options are successfully completed between this router and the remote device
- C . on this router can already ping through the peer address 6.6.6.2 that can not be judged by whether the verification, so the end does not necessarily address can ping through
- D . The interface information prompts that the second IP address subordinate can also be configured under this interface
The two routers of the customer are connected back-to-back via V.35 cable, and the PPP protocol is running on the V.35 interface , and the following interface information is on one of the routers:
[MSR-Serial0/0]display interface Serial 0/0
Serial6/0 current state: UP
Line protocol current state: DOWN
As can be inferred from the information ______ . (Multiple choices)
- A . The physical connection between the two routers is normal, but the PPP protocol negotiation is not successful
- B . PPP the LCP negotiation likely to fail
- C . PPP verification may have failed
- D . The IP addresses of the V.35 interfaces of the two routers may not be in the same network segment
ABC
Explanation:
Even if they are not in the same network segment, as long as the two ends are allocated addresses, the link layer protocol will be up
The main link of a company’s MSR router is the synchronous asynchronous serial port, which is connected to the operator’s network through a V.35 cable; the router also uses an ISDN BRI interface as a backup link.
So regarding line bandwidth, which of the following statements are correct ? (Multiple Choice)
- A . The bandwidth of the backup line may be 64Kbps
- B . The bandwidth of the backup line may be 128Kbps
- C . The bandwidth of the backup line may be 144Kbps
- D . The bandwidth of the main link may be 1Mbps
ABD
Explanation:
Two access methods of ISDN :
BRI interface → 2B + DB channel 64kbps D channel 16kbps maximum rate 144kbps
PRI interface → E1 30B + D maximum rate 2Mbps
T1 23B + D maximum rate 1.544Mbps
The B channel is used to transmit data, and the D channel is used to transmit control signaling, so the BRI provides a maximum bandwidth of 128 kbps (the amount of data that can be transmitted per unit time)
V . 24 Support same and asynchronous: asynchronous maximum rate 115kbps synchronous maximum rate 64kbps
V . 35 only supports synchronization: the highest rate is 2048000bps = 2Mbps
ping is actually an application developed based on the ______ protocol.
- A . ICMP
- B . IP
- C . TCP
- D . UDP
A
Explanation:
The ping function is implemented based on the ICMP protocol: after the source sends an ICMP echo request ( ECHO-REQUEST ) message to the destination, the destination is judged based on whether the destination ICMP echo reply ( ECHO-REPLY ) message is received It is reachable, for the purposes of end up, then according to the number of packets sent, number of packets received response to determine the quality of the link, according to ping between the destination packet round-trip time to determine the source of the " Distance " .
The IP address 203.108.2.110 is the ______ address.
- A . A Deliverable
- B . B class
CC class
DD type
The IP address 133.18.2.110 is the ______ address.
- A . A Deliverable
- B . B class
CC class
DD type
When the source host pings the destination device, if the network is working properly, the destination device will respond to the source host with an ICMP______ message after receiving the message.
- A . Echo Request
- B . Echo Reply
- C . TTL-Exceeded
- D . Port-Unreachable
B
Explanation:
Echo Request ――――――――――――――――――――――――――――> Echo Reply (Normal) <―――――――――――――― ―――――――――――――――
TTL-Exceeded / Port-Unreachable (timeout / destination address unreachable)
The broadcast address of the natural classification network segment corresponding to the IP address 125.1.1.1 is ____________ .
The broadcast address of the natural classification network segment corresponding to the IP address 125.1.1.1 is ____________ .
The number of available host addresses included in the natural classification network segment corresponding to the IP address 172.15.1.1 is ___________ . (Please fill in Arabic numerals)
The number of available host addresses contained in the natural classification network segment corresponding to the IP address 165.110.20.67 is (Please fill in Arabic numerals)
According to different sources, the routes in the routing table can generally be divided into the following categories ? (Multiple choice)
- A . Interface routing
- B . Direct connection routing
- C . Static routing
- D . Dynamic routing
The following statement about the IP address is correct ______ . (Multiple choices)
- A . The IP address can be fixed in the hardware and is a unique MAC
- B . IP addresses are divided into five categories : A , B , C , D , and E
- C . IP addresses are usually expressed in dotted hexadecimal, for example: 10.110.192.111
- D . The IP address is composed of 32 binary bits
BD
Explanation:
IP address dotted decimal:
A 1.0.0.0 ~ 126.255.255.255 127 is used as loop test 127.0.0.1 means this machine
B 128.0.0.0~191.255.255.255
C 192.0.0.0~223.255.255.255
D 224.0.0.0 ~ 239.255.255.255 multicast address
E 240 ~ Reserved for research
The network address of the natural classification network segment corresponding to the IP address 112.1.1.1 is.
The network address of the natural classification network segment corresponding to the IP address 112.1.1.1 is.
The IP address 192.48.117.22 corresponds to the network address of the natural classification network segment.
The IP address 192.48.117.22 corresponds to the network address of the natural classification network segment.
The following statement about the IP address is correct ______ . (Multiple choices)
- A . The IP address consists of two parts: the network number and the host number.
- B . The network number of a class A IP address has 8 digits, and the actual variable digits are 7 digits.
- C . Class D IP addresses are usually used as multicast addresses.
- D . Address translation ( NAT ) technology is usually used to resolve the translation of class A addresses to class C addresses.
ABC
Explanation:
The first 8 -bit 110 starting NAT of class C addresses is used for private network address to public network address translation, regardless of address type
The following statement about the IP address is wrong ______ . (Multiple choices)
- A . The IP address consists of two parts: the network number and the host number.
- B . The network number of a class A IP address has 8 digits, and the actual variable digits are 7 digits.
- C . The first octet of a class C IP address starts with 100 .
- D . Address translation ( NAT ) technology is usually used to resolve the translation of class A addresses to class C addresses.
CD
Explanation:
The first 8 -bit 110 starting NAT of class C addresses is used for private network address to public network address translation, regardless of address type
The following statement about the IP address is correct ______ . (Multiple choices)
- A . The IP address consists of two parts: the network number and the host number
- B . The first byte of class A address is 0 ~ 126 ( 127 is reserved for other purposes)
- C . IP addresses are usually expressed in dotted decimal format, for example: 10.110.168.121
- D . An IP address with a binary number of 1 in the host number is called a network address, and is used to identify all hosts on a network
AC
Explanation:
The first byte of class A address is 1 ~ 126
The following statement about the IP address is correct ______ . (Multiple choices)
- A . The first byte of class A address is 0 ~ 126 ( 127 is reserved for other uses)
- B . An IP address with a binary zero in the host number part is called a network address and is used to identify all hosts on a network.
- C . IP addresses are usually expressed in dotted decimal format, for example: 10.110.168.121
- D . The IP address consists of two parts: the network number and the host number
Which of the following options describe the parameters that can uniquely determine a TCP connection ?
- A . Source port number, source IP address
- B . Destination port number, destination IP address
- C . Source port number, destination port number
- D . Source MAC address, destination MAC address
- E . None of the above
E
Explanation:
The source IP address, source port, destination IP address, and destination port make up a socket, which uniquely determines a TCP connection
The TCP protocol uses ______ to distinguish between different connections.
- A . Port number
- B . Port number and IP address
- C . Port number and MAC address
- D . IP address and MAC address
The common fields of the UDP protocol and TCP protocol header are ______ . (Multiple choices)
- A . Source IP address
- B . Flow control
- C . Checksum
- D . Serial number
- E . Destination port
- F . Source port
CEF
Explanation:
UDP header: consists of source port, destination port, length, checksum
TCP header: source port, destination port, checksum, serial number, confirmation number, window, data is cheap, etc., to ensure the reliability of UDP protocol and TCP protocol header common fields: source port, destination port, calibration Checksum
The common fields in the UDP and TCP protocol headers are ______ . (Multiple choices)
- A . Source port
- B . Destination port
- C . Flow control
- D . Source IP address
- E . Checksum
- F . Serial number
During the establishment of the TCP connection as shown in the figure , the X part of the SYN should be filled with ________ .
- A . a
- B . b
- C . a+1
- D . b+1
C
Explanation:
X = a + 1 (confirm receipt of a , expect to send a + 1 next time )
Y = a + 1
Z = b + 1 (Confirm receipt b )
During the establishment of the TCP connection as shown in the figure , the Y part of SYN should be filled in ________ .
- A . a
- B . b
- C . a+1
- D . b+1
During the removal of the TCP connection as shown in the figure , the X part of the ACK should be filled with ______ .
- A . p
- B . q
- C . p+1
- D . q+1
C
Explanation:
X = p + 1 , B receives the connection termination request segment sent by A , confirms, and closes the connection at the same time
During the removal of the TCP connection as shown in the figure , the Y part of FIN should be filled with ______ .
- A . p
- B . q
- C . p+1
- D . q+1
The following description of the characteristics of the router is correct ______ . (Multiple choices)
- A . Is the network layer device
- B . Route forwarding based on link layer information
- C . Provide rich interface types
- D . Can support multiple routing protocols
ACD
Explanation:
Work on the bottom three
Route forwarding based on network layer information
Rich interface types, can be used to connect networks of different media
The following description of the characteristics of Comware , the correct one is ______ .
- A . Support IPv4 and IPv6 dual protocol
- B . Support multiple CPUs
- C . Fusion of routing and switching functions
- D . High reliability and flexible expansion
- E . Flexible cutting and customization functions
By (console Console fresh from the factory without configuration) port configuration MSR routers, terminal serial port baud rate should be set to _____ .
- A . 9600
- B . 2400
- C . 115200
- D . 38400
The following description about the characteristics of VTY in H3C equipment is correct ______ .
- A . Only used to Telnet the device
- B . Each device can support multiple VTY users to access simultaneously
- C . Each VTY user corresponds to a physical interface
- D . Does not support passwordless authentication
B
Explanation:
Vty is the virtual login interface, supports multiple users and supports authentication
Vty 0-4 5 interfaces, which can be accessed by 5 people at the same time
Logic lines 0-4 are randomly assigned. If 1-4 is turned off , only 0 is left , but it may not be randomly reached 0 , and it is still inaccessible
SSH uses TCP port number ______ by default .
- A . 20
- B . 21
- C . 22
- D . 23
If you need to configure the IP address of the Ethernet port on the MSR , it should be configured under ______ .
- A . System view
- B . User view
- C . Interface view
- D . Routing protocol view
The following statement about the upgrading of H3C network equipment is correct ______ . (Multiple choices)
- A . Using Xmodem to upgrade can achieve the same speed as FTP
- B . When using FTP to upgrade, the device can only be an FTP client
- C . When the device cannot boot to the command line mode and the operating system software needs to be upgraded, only the Xmodem mode can be used
- D . In an environment where the client and server are not easy to interact with, you can use TFTP to upgrade
D
Explanation:
The device can be used as a client or server
TFTP 69 Simple File Transfer Protocol
If you cannot enter the device, you can upgrade through ftp / tftp / Xmodem through the bootrom menu : when the device cannot boot to the command line mode and you need to upgrade the operating system software , use the operation function provided by the BOOTROM menu in the BOOTROM mode , using ftp / tftp enables the device to boot normally and boot into command line mode.
If the network connection between FTP and TFTP server and the device cannot be achieved , it is only adopted in the BOOTROM mode through the console port
Xmodem completes the upgrade and enables the device to boot normally to the command line mode
The following statement about the upgrade of H3C network equipment is correct ______ . (Multiple choices)
- A . Using Xmodem to upgrade can achieve the same speed as FTP
- B . When using FTP to upgrade, the device can be used as an FTP server or client
- C . When the device cannot be booted to the command line mode and the operating system software needs to be upgraded, Xmodem and TFTP modes can be used
- D . In an environment where the client and server are not easy to interact with, you can use TFTP to upgrade
BCD
Explanation:
Xmodem upgrade speed snail
The correct description of the startup process of the router system in the following options is ______ .
- A . memory test —— start bootrom —— application decompression ——- application loads
- B . Start bootrom —— memory test —— application loads
- C . Application decompression —— application loads —— startup bootrom —— memory test
- D . memory test —— application decompression —— Application Loader
A
Explanation:
Router system startup: memory detection> bootrom > application decompression> application loading