1. In the OSI seven-layer reference model, which layer does the common HTTP protocol belong to? ()
A. Application layer B. Data link layer C. Network layer D. Transport layer
OSI seven-layer reference model: ISO
application layer: application, human language -> coding, human-computer interaction
Presentation layer: convert coding into binary
session layer: data Encryption/encryption, session management, connection between two clients, such as private chat between QQ friends.
Transport layer: TCP/UDP, port number -0~65535, used to indicate different applications, port number used In order to mark the accuracy of the upper-layer (client, server) convenient transmission, among them, 0-1023 famous port number, 1024-65535 dynamic port number.
Network layer (router): IP, two versions, V4/V6-router, based on IP address is logically addressed (DHCP, OSPF, RIP)
Data link layer: MAC-switch, based on mac self-learning. . .
Physical layer: HUB
2. In the OSI seven-layer reference model, what is the address used by the transport layer? ()
A. Data B. Port number C. IP address D. MAC address
Use port number as address at the transport layer
3. For the following given conditions: a. The maximum transmission unit MTU of the destination network segment is 512 bytes; b. A 1500-byte datagram; c. A 20-byte IP header. The transmission equipment needs to divide the datagram into () segments to match the MTU of this network segment
. 1 B. 2 C. 3 D. 4
To transmit a 1500-byte datagram, the maximum transmission unit of the destination network segment is 512 bytes. A 20-byte IP header should be added for each transmission. In order to completely transmit the 1500-byte datagram, it should be
1500/(512-20)=3 and 24, and the remaining 24 should be transmitted again. , A total of 4 times
4. The corresponding relationship between the transport layer protocol and the port number below, the error is ()
A. DNS-TCP&UDP:53 B. SSH-TCP:22 C.TELNET-UDP23 D. DHCP-UDP:67&68 The
corresponding port number of TELNET is TCP
5. Which of the following is a usable IP address? ()
A. 192.168.22.31/27 B. 101.1.2.1/32 C. 235.102.1.20 D.202.201.1.222/30
First exclude options B and C. The mask of option B is 32, so no address is available; option C is not one Complete IP address
A complete IP address must have network bits, host bits, and mask
A 192.162.22.31/27—192.162.22.00011111. Host bits and host bits all 1 are broadcast address
D 202.201.1.222/30—202.201.1.11011110. Host bit
2^(Host bit) -2, the following 2 refers to the network segment and broadcast, "cut the beginning and ending" is the available address
6. Which of the following addresses can appear on the public Internet ()
A. 192.168.1.77/24 B. 172.33.44.55/24 C. 10.0.12.46/24 D. 172.16.17.124/24
IP addresses are classified according to the main class method, and class ABC becomes unicast addresses. Among them, unicast addresses can be divided into private addresses and public addresses.
Class A address: 0 XXXXXXX 0-127
Class B address: 10 XXXXXX 128-191 Class
C address: 110 XXXXX 192-223
Private address:
A:10.0.0.0 255.0.0.0
B:172.16.0.0–172.16.31.0.0 255.255 .0.0
C: 192.168.0.0--192.168.255.0 255.255.255.0
Except for private addresses, the remaining addresses in the ABC three categories are all public addresses.
Option A-Class C private address
Option B-Class B public address Option C-Class
A Private address
option D-Class B private address
7. The PC cannot connect to any remote website, cannot ping its default gateway, nor can it ping a working printer in the local network segment. Which of the following options can confirm whether the TCP/IP protocol stack on this PC is working properly? ()
A. Use the ipconfig /all command
at the command prompt of the host B. Use the ping 127.0.0.1 command at the command prompt
C. Use the traceroute command in the command prompt to find out any faults
in the gateway path D. Use the arp -a command in the command prompt
A.Ipconfig/all: View the local IP address and physical network card information
B.127.0.0.1 Local Loopback address, test whether the TCP/IP protocol stack can communicate normally (on behalf of the machine)
C.traceroute is used to track the routing path of network data packets
D.Arp-a is used to query the MAC address
8. There are 4 routes in the routing table, 10.0.0.0/24, 10.0.1.0/24, 10.0.2.0/24, 10.0.3.0/24. If route aggregation is to be performed, the most suitable route after aggregation is ()
A . 10.0.0.0/22 B. 10.0.0.0/23 C. 10.0.0.0/24 D. 10.0.0.0/25
Subnet summary method: take the same bit and go to
the top ten of the four IP addresses in the question The six digits are the same, so split the last sixteen digits to write
10.0.00000000.00000000/24
10.0.00000001.00000000/24
10.0.00000010.00000000/24
10.0.00000011.00000000/24 to make the IP reach the maximum digit, so borrow two digits, 10.0.0.0 /twenty two
9. Divide the network of 200.200.201.0 into subnets. It is required to divide as many network segments as possible, but each network segment cannot be less than 5 computers. The subnet mask of the subnet is ()
A. 255.255.255.240 B. 255.255.255.252 C. 255.255.255.248 D. 255.255.255.0
A mask is 28, available address is 2^4-2-14
B mask is 30, available address is 2^2-2-2
C mask The code is 29, and the available address is 2^3-2-6
. The mask is 24. The available address is 2^8-2—254.
A and D are too many available addresses, causing waste, and B’s available addresses are not enough, although C has one available address remaining , But just enough
10. In Huawei equipment, how can I check whether all the entered commands are valid? ()
A. display current-configuration B. display ip interface brief
C. display ip routing-table D. display arp all
A. Check whether the typing command takes effect
B. Check the device interface summary information
C. Check the routing table
D. Check the local ARP information ( MAC) MAC/Physical Address
2.
Fill in the blank questions (32 points) 1. The management port IP of a router is 10.111.222.33/30. If the computer needs to log in to the router through this IP, then the computer's own IP needs to be set to _________________, and the mask is set to ________________ .
It can be judged that the network segment of the IP address is 10.111.222.32/30, and the
next IP network segment is 10.111.222.36/30. The
available IP addresses are 10.111.222.33/30&10.111.222.34/30
2. A router receives two routes with the same target network number, one is learned through OSPF and the other is learned through RIP. At this time, which route will the router choose to add to the table? The reason is: ______________.
When two routes go to the same target network segment, if there are multiple paths to choose from, the priority of these paths will be checked first
; if the priorities are the same, the cost value will be checked, and the cost value will be checked.
If they are all the same, the multiple paths will be loaded into the routing table to achieve load balancing.
The OSPF priority is 10, and the RIP priority is 100.
3. In Ethernet, the RJ-45 twisted pair T-568B line sequence is ____________________________, _______ lines are used between devices on the same layer, and ________ lines between devices on different layers.
The line sequence of T-568B is orange-white, orange, green-white, blue, blue-white, green, brown-white, brown
. Use crossover cables between devices on the same layer, and use straight-through cables between different devices.
4. _________ is also called transmission control protocol, which is a connection-oriented, reliable, byte stream-based __________ layer communication protocol
TCP transmission control protocol, and a connection-oriented reliable transmission protocol. Transport layer communication protocol based on byte stream
5. Adding the default gateway IP to the local network card of the Windows computer is equivalent to configuring the _________ route on the router.
Default route or default route
6. The main function of VLAN is ____________. Please write down the scope of Huawei switch VLAN_____________
VLAN virtual local area network. The original broadcast domain is logically divided into multiple broadcast domains
. The main function of VLAN: Let the switch follow Different VLANs send data to realize the isolation of broadcast domains.
Range 1-4094
7. The TRUNK link in Huawei switches only allows VLAN______ to pass by default, and VLAN_____ does not need to be tagged by default.
In Huawei switches, each port is divided into VLAN1 by default. Only VLAN1 without tag
3. Short answer questions (48 points)
1. Please write down the contents of DHCP technology
1) Basic concepts and functions
DHCP: dynamic host configuration protocol
Based on UDP protocol, port number 67&68 is
based on Client/Server structure
Function: unified distribution and management of IP addresses
2 ) Describe the working process in combination with the DHCP data packet
. After the client that needs to automatically obtain the IP address turns on the automatic acquisition of the IP address, the local broadcast sends out a DHCP Discover packet, the
source IP address is 0.0.0.0, the destination IP address is 255.255.255.255, and the source MAC address is local The network card MAC, the destination MAC is FFFF-FFFF-FFFF, the
source port is 68, and the destination port is 67;
after receiving this packet, the server with DHCP service will send a gratuitous ARP to ensure that the IP address to be issued is not conflicted, and then The local replies to the DHCP Offer packet based on broadcast, the
source IP is the server IP address, the destination IP address is 255.255.255.255, the source MAC is the server network card MAC, the destination MAC is FFFF-FFFF-FFFF, the
source port is 67, and the destination port is 68 ; The
client uses a DHCP Request packet to request an IP address, the server replies an ACK to the client, and the client gets the IP address.
2. Please write the relevant content of the dynamic routing protocol OSPF
1) Basic concept
Open Shortest Path First, the open shortest path first protocol
Multicast sending: 224.0.0.5/6
standard link state routing protocol-routing topology between routers
Version: OSPFv2–IPv4 OSPFv3–IPv6
update method: Trigger the update existence cycle update 30min
OSPF network needs to be structured deployment: 1, area division 2, IP address planning
link state routing protocol distance vector characteristics-intra-area transfer topology, Transfer routing tables between areas
Priority 10 COST value = reference bandwidth ÷ interface bandwidth
2) Data packets and role
hello packets: used to discover, establish and keep alive (10s) neighbor relationships. There is a unique Router-ID in the entire network, which is used to identify the router. The IP address used means
DD package: Database Description, database description package
LSR: link state request
LSU: link state update
LSAck: link state confirmation
3) State machine and function
down: the protocol is not started. Once the protocol is started and the hello packet is sent, it immediately enters the next state
init: waiting for the neighbor to reply. If the received hello packet carries its own RID, it will enter the next state with the other party.
2-way: indicates that the neighbor relationship is established. The
condition matches: if it succeeds, it will enter the next state; if it fails, only the hello packet will keep alive
exstart : Pre-start, use fake DD message to compare RID, the larger one will enter the next state first.
exchange: Both parties exchange DD packets.
Loading: Use LSR/LSU/LSAck to obtain unknown path topology or route
full: Adjacency is established and convergence is completed.
3. Please write the relevant content of ACL technology
1) ACL concept and function
Access Control List, Access Control List
Function:
1. Realize access control
2. Grab interesting traffic for other technologies to call
2) ACL classification and characteristics
Basic ACL: only It can match the source IP address in the data packet.
Advanced ACL: It can identify the source and destination IP addresses, source and destination port numbers and protocol numbers in the data packet.
3) ACL matching rules
are matched in sequence from top to bottom. Once the traffic is matched, Do not view the next one.
4. Additional questions (10 points)
(Experimental analysis) The topology is shown in the figure below. The AR2 router is the border device of the company to connect to the Internet. What do the internal computers of the company need to configure on AR2 if they want to go online?
- Configure the corresponding IP address on port 0/0/1 of AR2,
- Configure the public IP on port 0/0/1 of AR2
- Configure easy-NAT on port 0/0/1, private network to public network
- Configure the default route on port 0/0/1 so that AR2 can access the IP
- Configure the intranet backhaul route on port 0/0/0 of AR2 to make the entire intranet reachable