Network Fundamentals
3. Which layer of the OSI 7-layer network model does the hub work on? D
A, Transport layer
B, Network layer
C, Data link layer
D, Physical layer
4. In the following options, the error about the protocol and the default port number is D POP is 25 SMTP is
A, HTTP default to use 80 port
B. Telnet uses port 23 by default
C, FTP default to use 20, 21 port
D, SMTP uses port 110 by default
IP Subnets
3. What are the types of IPV6 addresses? What's the difference? (5 points)
Global Unicast Address 2000::/3
Link-Local address FE80::/10
Multicast address FF00::/7
Unique Local address FC00::/7
6to4 tunnel Address: 2002::/16
Device Management
1. IOS for Cisco routers is stored in (D)
A, RAM
B, ROM
C, NVRAM
D, Flash
8. When in a long ping, want to stop one of the ways to use? C
A, CTRL + Z
B, CTRL + C
C, Ctrl+shift+6
D, Ctrl+r
3. When configuring Telnet, there are three types of logins, please say the difference (6 points)
Login: Requires a password to log in
Login Local: User name and password required to log in
No login: No password required to log in
5. Please write out the key steps and commands of Cisco router password recovery. (10 points)
1. Restart, press and hold Ctrl+break (or CTRL + C) when power is added.
2. Enter Remmon mode, input Confreg 0x2142 (4 = Skip startup-config)
3. Reset Restart Skip Configuration Wizard
4. Change the password
5. Enter Config-register 0x2102 Recovery Register Value
6. Please write out the key steps, commands (10 points) to upgrade Cisco router IOS
1. Back up iOS files, and Startup-config
First put the TFTP or FTP server on the PC, connect the router's Ethernet port to the PC's NIC port, configure the IP address of the same network segment,
Check connectivity.
Then copy flash:tftp: or copy flash:ftp: (depending on the client settings on your PC),
Source filename []? Fill in according to actual situation
Address or name of remote host []? fill in the IP address of the PC network card you configured
It is recommended to pass through the Ethernet port instead of the console port because it is much faster
2. Copy the iOS and startup-config files of the TFTP or FTP server to the router
Copy Tftp:flash: You will also encounter the problem of the previous step, so fill in
Copy Ftp:flash:
3. Copy Startup-config to NVRAM
Copy Flash:startup-config Nvram:startup-config
4. restart
USB flash drive upgrade with copy Usbflash0:flash: same Note backup
Static Routes
2. What are the administrative distances and measures that are displayed in the routing table for static routes that point to the next hop IP? C
A, the management distance is 0, the measure is 0
B, management distance is 0, measure is 1
C, the management distance is 1, the measure is 0
D, management distance is 1, measure is 1
RIP
1. RIPV2 Update the address of the routing information (A)
A, 224.0.0.9
B, 224.0.0.10
C, 224.0.0.5
D, 224.0.0.6
2. In RIP routing, the maximum number of hops that can be added to the routing table is (B)
A, 16
B, 15
C, 255
D, 65535
4. What port does RIP use to update messages? B
A, TCP 520
B, UDP 520
C, TCP 23
D, UDP 120
10. How long will this route be removed from the routing table after the invalid route marked by RIP routing on the router_1 router? (E)
A, Seconds
B, Seconds
C, Seconds
D, the Seconds
E, Seconds
1. What are the anti-ring mechanisms used to write the distance vector routing protocol (RIP as an example)? (10 points)
Maximum hop count
Split horizontally
Toxicity reversal
Holdown Time
2. What are the default times for RIP to use several timers? (10 points)
Update Timer: 30
Suppression Timer: 180S
Refresh timer: 240S
EIGRP
1. Which parameter does not participate in the metric calculation of EIGRP? F
A. Bandwidth
B. Delay
C. Reliability
D. Loading
E. MTU
F. Cost
OSPF ( the larger the value the higher the precedence)
1. Write down the prerequisites for the OSPF build neighborhood you know and briefly describe the process of OSPF building a neighbor. (10 points)
1) OSPF router interface up, send Hello packet, (NBMA mode will enter attempt state).
2) The OSPF router interface receives the Hello packet, enters the Init state, and adds the Router ID of the sender of the Hello packet to the
The neighbor list of the Hello package (the Hello package that you are going to send out from this interface).
3) The OSPF router interface receives a HELLO packet with its own Router ID in the other data list, enters the two-way state, forms the OSPF
Neighbor, and adds the Router ID of the router to its own OSPF neighbor table.
4) After entering the two-way state, broadcast, non-broadcast network type of link in Dr Election wait time for Dr election, point to
Point does not have this process.
5) After Dr Election is completed, or after the Dr election, establish OSPF adjacency relationship, enter the Exstart (quasi-start) state;
The DBD exchange master-slave router, as well as the main router defines the DBD serial number, Router ID large primary router, the purpose is
In order to solve the DBD's own reliability.
6) after the master-slave router election is completed, enter Exchange (Exchange) status, exchanging DBD information.
7) When the DBD switch is completed, enter the Loading state, compare the link state database to the LSA header of the received DBD, and find the LSA in its own database to send the LSR, requesting the LSA from the neighbor; the neighbor receives the LSR, responds to LSU; LSU, which stores these LSA to its own link-state database, and sends a lsack acknowledgment.
8) After the LSA Exchange is complete, the full state is entered, and all OSPF routers that form the neighbor have the same link state database.
9) Send the Hello packet periodically to maintain the neighbor relationship.
3. Under what circumstances will OSPF elect Dr and BDR? How to make OSPF do not elect DR and BDR for network when unnecessary
Optimization? (5 points)
4. What are the terms of reference when electing DR? (5 points)
Router (CONFIG‐IF) #ip OSPF priority 10 is manually modified, 0 is not elected
Election rules:
1) Comparison of priority levels
2) Router ID
3) Priority 0 cannot be a DR or BDR
5. What are the multicast addresses used by OSPF? What is the multicast address that only the DR and BDR will listen to? (5 points)
224.0.0.5 and 224.0.0.6, DR, BDR will have additional monitoring 224.0.0.6
7. Compare the OSPF and EIGRP routing protocols and write down the advantages and disadvantages that you consider to be unique. (10 points)
EIGRP supports more protocols, such as IPX, IPv6, ospfv2 only support IPv4
Eigrp converges slightly faster
EIGRP supports not-equivalent load balancing, OSPF only supports equivalent load balancing
EIGRP is a distance vector protocol, convergence hop-by-step convergence, OSPF is a link-state protocol, almost synchronous convergence within the region
EIGRP does not support tiering, OSPF can be layered, multi-region, for larger networks
VLAN, TRUNK, VTP, Etherchannel
5 Complete the table below
| Package Type |
If you need to modify the original frame |
Efficiency |
| ISL (Cisco dedicated) |
No need to add ISL frames to head and tail |
High, no need to change the original check value |
| 802.1q (Universal) |
Add a VLAN header after the original frame header |
Lower because the header is inserted into the VLAN, so it needs to be re-calibrated, but Vlan1 and previously compatible, are currently mainstream |
What are the characteristics of 6 Nativevlan?
For 802.1q, the native VLAN is compatible with the original LAN format and does not include a new packet header (that is, a VLAN that does not tag).
7 If IP address is configured on the physical interface, the% IP addresses may
notbeconfiguredonl2links. Error? How can I operate the implementation?
when a port is a two-layer port, the address cannot be configured, and the router's switching module can be implemented
available on the interface of the three-layer switch: No switchport two-layer interface into a three-layer interface to configure IP
What is the multicast address for 8 VTP?
Multicast MAC 01:00:0c:cc:cc:cc
Send multicast on VLAN1
11 Is it possible to establish success with PAgP different models when setting up EtherChannel?
| Mode |
On |
Desirable |
Auto |
| On |
Can |
Not |
Not |
| Desirable |
Not |
Can |
Can |
| Auto |
Not |
Can |
Not |
(i.e. at least one desirable)
12 can the different models of LACP be successful when establishing EtherChannel?
| Mode |
On |
Active |
Passive |
| On |
Can |
Not |
Not |
| Active |
Not |
Can |
Can |
| Passive |
Not |
Can |
Not |
(that is, there is at least one active)
Spanning Tree (the smaller the number the higher the precedence)
1 Write out the 4 procedures for the STP operation. (10 points)
1) Election of one Root bridge (Rootbridge) in each switching network (broadcast domain)
2) Election of a root port on each non-root bridge (root)
3) elect a designated port for each Segment (designated port)
4) block non-specified ports (non-designated port)
2 Write the election reference parameters for the root bridge. (10 points)
The switch with the smallest bridge ID becomes the root bridge. Compare the bridge priority when comparing, if everyone's bridge priority is the same, then further
Compare the MAC address of the switch and choose the smallest one. Note that the MAC address here does not refer to the Mac of an interface of the switch,
instead it's the backplane MAC address.
3 Write the election principle of the root port. (10 points)
1) The lowest root Path cost to the root bridge
2) Lowest sender Bridge ID
3) Lowest sender Port ID
4 Write the election principle for the specified port. (10 points)
1) The lowest root Path cost to the root bridge
2) Lowest sender Bridge ID
3) Lowest sender Port ID
What is the sending interval for 5 BPDUs? How long does it take for an interface to switch from blocked state to listening state? When forwarding a delay
What 's the room? (10 points)
The default of 2 seconds, blocking to listen requires 10 times times the BPDU time, is 20s.
Forward Delay Timer defaults to 15S, which is listen-learning (15s), or learning-forwarding (15s).
7 What is the cost of the 100M link in the new standard? (10 points)
| Link bandwidth (MB/s) |
Path cost |
| 10 |
100 |
| 16 |
62 |
| 45 |
39 |
| 100 |
19 |
| 155 |
14 |
| 622 |
6 |
| 1000 |
4 |
| 10000 |
2 |
9 What type of spanning tree does the Cisco switch turn on by default? What is the difference between this spanning tree and the standard spanning tree? (10 points)
pvst+, Support per VLAN spanning tree, incompatible with standard spanning tree
10 What are the spanning trees supported by the Cisco switch? What type of spanning tree should I use when interfacing with other vendor switches? (10 points)
the spanning tree supported by the Cisco switch has PVST+,RPVST+,MST, and other vendors can only use MST
FHRP
5 Simple analysis of the difference between three protocols (20 points)
HSRP,GLBP is Cisco Private, VRRP public, VRRP default preemption, and can use the actual address as the forwarding address, VRRP state machine simple, less type of message, HSRP can be directly track address, GLBP features in the group other members can also be used to forward part of the data, For core routers, such as the 65 series, general access switches are not supported.
ACL
1 Simple description of the difference between standard ACL and extended ACL (10 points)
The standard ACL can only match the source or destination, and the extended ACL table has more matches than the standard ACL, including protocol type, source address, destination address, source port, destination port, established connection and IP precedence, etc.
2 when a packet enters an interface configured with ACLs, is it first to check the ACL or query the route first? (10 points)
ACL is higher than route
3 When an ACL is configured on an interface with a packet-out direction, is the ACL checked first or Anza? (10 points)
route higher than ACL
5 is the ACL written below reasonable? (10 points)
Access-list 1 Deny 192.168.1.0
Access-list 1 Deny 192.168.1.0 0.0.0.255
Did not write permit any
PPP
1 What are the three types of WAN data link layer encapsulation? (10 points)
FR Frame Relay, PPP point-to-point, HDLC Advanced Link Control Protocol
2 What are the two sub-tiers of PPP? (10 points)
LCP (Link Control Protocol) and NCP (Network Control Protocol)
3 What are the two types of PPP verification capabilities? (10 points)
PAP and CHAP
5 PPP protocol supports authentication, which is responsible for authentication in LCP and NCP? (10 points)
LCP Link Control Protocol
6 Brief description of the difference between PAP and CHAP protocol (20 points)
PAP plaintext, chap only sends hash value, pap two-time handshake, chap three-time handshake
7 in the serial link, using the PPP protocol and using authentication, found that OSPF neighbors can not be established, how to determine that the PPP authentication has appeared
questions or other reasons? Verify with one command (20 points)
an easier way to directly sh int sx/x See is not the physical up protocol down, you can see the LCP state
Network Fundamentals 8) write out a typical PDU package format containing 4 layers 3 layers 2 layers.
Destination mac. Source Mac | Source IP. Destination IP | Source port. Destination Port | DATA 10) How many bits share population the transport layer? How many bits does the network layer IP occupy? How many bits does MAC address occupy? The source port each occupies 16 bits. The source IP each accounted for 32 bits. SOURCE MAC 48-bit
What are the private addresses in IPV4?
10.0.0.0/8-10.255.255.255/8
172.16.0.0/16-172.31.255.255/16
192.168.0.0/24-192.168.255.255/24) What is the address of 127.x.x.x? What's the address of 169.254.x.x?
127 address that starts with the PC local loopback address 169.254.x.x as the Microsoft operating system fails after DHCP is assigned
17) where is the router startup-config stored? Where is the running-config stored?
Startup-config stored in NVRAM
Running-config put in memory 18) Router Telnet login Verify what 4 authentication methods are available?
does not validate
Password verification
Local user name + password Authentication AAA server Authentication
21) Write the 568A and 568B standard line sequence of twisted pair (network cable). T568A: Green white green orange white blue blue white orange brown white brown t568b: orange white orange green white blue blue white green brown white Brown 23) What two types of optical fiber are divided into? What are the characteristics of each?
Multimode, single-mode;
Multimode: Short transmission distance, visible Singlemode: long transmission distance; not visible
Routing 1) What are the three principles for router routing? Maximum mask match; AD value min metric 5) How does OSPF perform cost calculation?
100/Bandwidth =cost 7) What is the DR election principle of OSPF?
The greater the priority, the better
Router-id better 8) What type of network does OSPF need for DR elections?
Broadcast multi-access and non-broadcast multi-access 9) What is the default network type for OSPF running in an Ethernet environment?
Broadcast multiple Access One) what is the default network type for the GRE tunnel tunnel running OSPF?
NBMA non-broadcast multi-access 13) What is the command to manually modify the cost value of OSPF under the interface?
IP OSPF cost xx) What is the command to modify the reference bandwidth under the OSPF process?
Auto-cost reference-bandwidth xx) What is the full name of the ABR and ASBR in OSPF?
ABR: regional border router;
ASBR: Autonomous domain system border router;
Exchange 1) What are the three functions of the switch?
MAC Address Learning
Forwarding filtering function Loop avoidance 2) What content is stored on the Switch CAM table?
MAC address
Port number
VLAN number 4) What is the technology that limits the number of switches MAC learning?
Switch port Security 6) Does the broadcast domain become more or less after the switch configures the VLAN? What about the conflict zone?
Each VLAN belongs to a broadcast domain. The number of broadcast domains is more. The range decreases for each port of the switch is a conflicting domain. Number unchanged
What is the characteristics of the Native Vlan, which is unique in the package?
dot1q
by trunk without VLAN tags) What is the EC full name? What is its role? What are the two types of agreements?
Ethernet channel, which bundles multiple physical interfaces into one logical interface, increasing the bandwidth to provide redundancy PAGP LACP
16) What are the four port states that the standard STP needs to undergo?
What is the full name of SNMP for blocking, listening, learning, and forwarding? What is the difference between its functional and syslog system logs? Simple Network Management Protocol logs can only view system log information. SNMP can see richer device information and can modify the configuration
Acl&nat 1) What are the two types of IP-based ACLs? Which elements can be controlled separately?
Standard ACLs and extended ACLs.
Standard ACL: The source IP extension ACL can be controlled: protocol can be controlled. Source IP and Port
2) What are the two parts of the general ACL configuration?
The ACL is defined first in the global context. Again in the interface down with ACL 4) ACL in addition to the application of the interface to do data flow control, which can also be used in which situations?
Nat Source Address translation range, Telnet limit 6) PAT is taking advantage of what two pairs of features are in the conversation?
ip+ Port 7) What does overload mean in PAT configuration?
Address reuse. That is, using the same IP different ports to drive intranet access
WAN 5) What is the full name of the VPN? What is the difference between LAN and LAN communication using WAN and VPN?
Virtual Private Use
WAN requires leased line support VPN to set up tunnels directly on the internet
Ipv6&wlan 1) How many bits does the IPV6 address have?
128 bit 4) What protocol does the IPv6 cancel the ARP with instead?
ICMPV6 5) What does the IPV6 link local address start with? FE80:6) write out the command to turn on the IPV6 function on the router IPv6 unicast-routing 7) write the maximum transfer rate 802.11a/b/g/n/ac
802.11g:54mb
802.11n:600mb
802.11ac:1000mn 8) Write out three ways of WLAN encryption? WEP WPA WPA2
CCNA Theoretical knowledge loopholes
