ccna Flashcards
(124 cards)
1
Q
What is Routing?
A
Routing is the process of finding a path on which data can pass from source to destination. Routing is done by a device called routers, which are network layer devices.
2
Q
What is the purpose of the Data Link?
A
The job of the Data Link layer is to check messages are sent to the right device. Another function of this layer is framing.
3
Q
What is the key advantage of using switches?
A
When a switch receives a signal, it creates a frame out of the bits that were from that signal. With this process, it gains access and reads the destination address, after which it forwards that frame to the appropriate port. This is a very efficient means of data transmission, instead of broadcasting it on all ports.
4
Q
When does network congestion occur?
A
Network congestion occurs when too many users are trying to use the same bandwidth. This is especially true in big networks that do not resort to network segmentation.
5
Q
What is a Window in networking terms?
A
A Window refers to the number of segments that are allowed to be sent from source to destination before an acknowledgment is sent back.
6
Q
Does a bridge divide a network into smaller sections?
A
Not really. What a bridge actually does is to take the large network and filter it, without changing the size of the network.
7
Q
Which LAN switching method is used in CISCO Catalyst 5000?
A
CISCO Catalyst 5000 uses the Store-and-forward switching method. It stores the entire frame to its buffers and performs a CRC check before deciding whether or not to forward that data frame.
8
Q
What is the role of the LLC sublayer?
A
The LLC sublayer stands for Logical Link Control. It can provide optional services to an application developer. One option is to provide flow control to the Network layer by using stop/start codes. The LLC can also provide error correction.
9
Q
How does RIP differ from IGRP?
A
RIP relies on the number of hops in order to determine the best route to a network. On the other hand, IGRP takes consideration many factors before it decides the best route to take, such as bandwidth, reliability, MTU and hop count.
10
Q
What are the different memories used in a CISCO router?
A
Different memories used in a CISCO router are:
- NVRAM stores the startup configuration file.
- DRAM stores the configuration file that is being executed.
- Flash Memory - stores the Cisco IOS.
11
Q
What is BootP?
A
BootP is a protocol that is used to boot diskless workstations that are connected to the network. It is short for Boot Program. Diskless workstations also use BootP in order to determine its own IP address as well as the IP address of the server PC.
12
Q
What is the function of the Application Layer in networking?
A
The Application Layer supports the communication components of an application and provides network services to application processes that span beyond the OSI reference model specifications. It also synchronizes applications on the server and client.
13
Q
What’s the difference between User Mode from Privileged Mode?
A
User Mode is used for regular task when using a CISCO router, such as to view system information, connecting to remote devices, and checking the status of the router. On the other hand, privileged mode includes all options that are available for User Mode, plus more. You can use this mode in order to make configurations on the router, including making tests and debugging.
14
Q
What is 100BaseFX?
A
This is Ethernet that makes use of fiber optic cable as the main transmission medium. The 100 stands for 100Mbps, which is the data speed.
15
Q
Differentiate full-duplex from half-duplex.
A
In full-duplex, both the transmitting device and the receiving device can communicate simultaneously, that is, both can be transmitting and receiving at the same time. In the case of half-duplex, a device cannot receive while it is transmitting, and vice versa.
16
Q
What is MTU?
A
MTU stands for Maximum Transmission Unit. It refers to the maximum packet size that can be sent out onto the data line without the need to fragment it.
17
Q
How does cut-through LAN switching work?
A
In Cut-Through LAN switching, as soon as the router receives the data frame, it will immediately send it out again and forward it to the next network segment after reading the destination address.
18
Q
What is latency?
A
Latency is the amount of time delay that measures the point from which a network device receives a data frame to the time it sends it out again towards another network segment.
19
Q
Utilizing RIP, what is the limit when it comes to the number of hops?
A
The maximum limit is 15 hop counts. Anything higher than 15 indicates that the network is considered unreachable.
20
Q
What is a Frame Relay?
A
Frame Relay is a WAN protocol that provides connection-oriented communication by creating and maintaining virtual circuits. It has a high-performance rating and operates at the Data Link and Physical Layers.
21
Q
How do you configure a Cisco router to route IPX?
A
The initial thing to do is to enable IPX routing by using the “IPX routing” command. Each interface that is used in the IPX network is then configured with a network number and encapsulation method.
22
Q
What are the different IPX access lists?
A
There are two types of IPX access lists
- Standard
- Extended
Standard Access List can only filter the source or destination IP address. An Extended Access List uses the source and destination IP addresses, port, socket, and protocol when filtering a network.
23
Q
Explain the benefits of VLANs.
A
VLANs allow the creation of collision domains by groups other than just physical location. Using VLANs, it is possible to establish networks by different means, such as by function, type of hardware, protocol, among others. This is a big advantage when compared to
conventional LANs wherein collision domains are always tied to physical location.
24
Q
What is subnetting?
A
Subnetting is the process of creating smaller networks from a big parent network. As a part of a network, each subnet is assigned some additional parameters or identifier to indicate its subnet number.
25
What are the advantages of a layered model in the networking industry?
A layered network offers many advantages. It allows administrators to make changes in one layer without the need to make changes in the other layers. Specialization is encouraged, allowing the network industry to make progress faster. A layered model also
lets administrators troubleshoot problems more efficiently.
26
Why is UDP lease favored when compared to TCP?
It's because UDP is unreliable and unsequenced. It is not capable of establishing virtual circuits and acknowledgments.
27
What are some standards supported by the Presentation layer?
Presentation layer supports many standards, which ensures that data is presented correctly. These include PICT, TIFF, and JPEG for graphics, MIDI, MPEG and QuickTime for Video/Audio.
28
What's the easiest way to remotely configure a router?
In cases when you need to configure a router remotely, the most convenient is to use the Cisco AutoInstall Procedure. However, the router must be connected to the WAN or LAN through one of the interfaces.
29
What does the show protocol display?
- routed protocols that is configured on the router.
- the address assigned on each interface.
- the encapsulation method that was configured on each interface.
30
How do you depict an IP address?
It can be done in three possible ways:
- using Dotted-decimal. For example: 192.168.0.1
- using Binary. For example: 10000010.00111011.01110010.01110011
- using Hexadecimal. For example: 82 1E 10 A1
31
How do you go to privileged mode? How do you switch back to user mode?
To access privileged mode, you enter the command "enable" on the prompt. In order to get back to user mode, enter the command "disable."
32
What is HDLC?
HDLC stands for High-Level Data Link Control protocol. It is a propriety protocol of CISCO. It is the default encapsulation operated within CISCO routers.
33
How are internetworks created?
Internetworks are created when networks are connected using routers. Specifically, the network administrator assigns a logical address to every network that connects to the router.
34
What is Bandwidth?
Bandwidth refers to the transmission capacity of a medium. It is a measure of how much volume a transmission channel can handle, and it is measured in Kbps.
35
How does Hold-downs work?
Hold-downs prevent regular update messages from reinstating a downed link by removing that link from update messages. It uses triggered updates to reset the hold-down timer.
36
What are packets?
Packets are the results of data encapsulation. These are data that have been wrapped under the different protocols of the OSI layers. Packets are also referred to as datagrams.
37
What are segments?
Segments are sections of a data stream that comes from the upper OSI layers and ready for transmission towards the network. Segments are the logic units at the Transport Layer.
38
Give some benefits of LAN switching.
- allows full duplex data transmission and reception
- media rate adaption
- easy and efficient migration
39
What is Route Poisoning?
Route Poisoning is the process of inserting a table entry of 16 to a route, making it unreachable. This technique is used in order to prevent problems caused by inconsistent updates on a route.
40
How do you find valid hosts in a subnet?
The best way to go about this is to use the equation 256 minus the subnet mask. The hosts that are considered valid are those that can be found between the subnets.
41
What is DLCI?
DLCI, or Data Link Connection Identifiers, are normally assigned by a frame relay service provider in order to uniquely identify each virtual circuit that exists on the network.
42
Briefly explain the conversion steps in data encapsulation.
From a data transmitter's point of reference, data from the end user is converted to segments. Segments are then passed on to the other layers and converted into packets or datagrams. These packets are then
converted into frames before passing on to the
network interface. Finally, frames are converted to bits prior to actual data transmission.
43
What are the different types of passwords used in securing a CISCO router?
There are actually five types of passwords that can be used. These enable secret, virtual terminal, console, and auxiliary.
44
Why is network segmentation a good idea when managing a large network?
For a network administration, segmenting a network would help ease network traffic and ensures that high bandwidth is made available at all times for all users. This translates to better performance, especially for a growing network.
45
What are the things that can be accessed in a CISCO router's identifying information?
The hostname and the Interfaces. The hostname is the name of your router. The Interfaces are fixed configurations that refer to the router ports.
46
Differentiate Logical Topology from Physical Topology
Logical Topology refers to the signal path through the physical topology. Physical Topology is the actual layout of the network medium.
47
What causes a triggered update to reset the router hold-down timer?
This may happen when the hold-down timer has already expired, or when the router received a processing task that incidentally was proportional to the number of links in the internetwork.
48
In configuring a router, what command must be used if you want to delete the configuration data that is stored in the NVRAM?
erase startup-config
49
Referring to the commands shown, what command must next be used on the branch router prior to traffic being sent to the router?
(config-if)# dialer-group 1
50
When configuring a router utilizing both physical and logical interfaces, what factor must be considered in determining the OSPF router ID?
The highest IP address of any physical interface.
51
What is the difference between the switch, hub, and router?
Hub has a single broadcast domain and collision domain. Anything comes in one port is sent out to the
others.
Switch is a device that filters and forwards packets between LAN segments. Switches have a single broadcast domain and multiple collision domains. It supports any packet protocol, as such it operates at the data link layer 2 and layer 3.
Router is a device which transmits data packets along
networks.
52
What is the size of IP address?
Size of IP address is 32 bit for IPv4 and 128 bit for IPv6
53
Mention what does data packets consist of?
A data packet consists of sender’s information, recipient’s information, and the data contained. It also has the numeric identification number that defines the packet number and order. When data is sent across the network, that information is segmented into data
packets. In short, data packets carry the information and routing configuration for your transferred message.
54
What is DHCP stand for?
DHCP stands for Dynamic Host Configuration Protocol. DHCP assigns an IP address automatically to a given workstation client. You can also make static IPS for machines like printers, servers, routers, and scanners.
55
Mention what BOOTP is?
BOOTP is a computer networking protocol used to deploy an IP address to network devices from a configuration server.
56
Explain why UDP is lease favored when compared to TCP?
It is because UDP is un-sequenced and unreliable. It is not capable of creating virtual circuits and acknowledgments.
57
State the difference between dynamic IP and static IP addressing?
Dynamically IP addresses are provided by DHCP server, and static IP addresses are given manually.
58
Mention the ranges for the private IP?
Ranges for private IP are
• Class A: 10.0.0.0 – 10.0.0.255
• Class B: 172.16.0.0 – 172.31.0.0
• Class C: 192.168.0.0 – 192.168.0.255
59
In how many ways you can access the router?
You can access it in three ways
• Telnet (IP)
• AUX (Telephone)
• Console (Cable)
60
What is EIGRP?
EIGRP stands for Enhanced Interior Gateway Routing Protocol it is a routing protocol designed by Cisco Systems. It is availed on a router to share routes with other routers within the same autonomous system. Unlike other routers like RIP, EIGRP only sends
incremental updates, decreasing the workload on the router and the amount of data that needs to be transferred.
61
Mention what is the matric of EIGRP protocol?
```
EIGRP protocol consists of
• Bandwidth
• Load
• Delay
• Reliability
• MTU
• Maximum Transmission Unit
```
62
Mention what does the clock rate do?
Clockrate enables the routers or DCE equipment to communicate appropriately.
63
Mention what command you must use if you want to delete or remove the configuration data that is stored in the NVRAM?
Erase startup- coding is the command you must use if you want to delete the configuration data that is stored in the NVRAM.
64
What is the difference between TCP and UDP?
TCP and UDP both are protocols for sending files across computer networks.
TCP (Transmission Control Protocol)
TCP is connection oriented protocol. When connection lost during transferring files, the server would request the lost part. While transferring a message, there is no
corruption while transferring a message. The message will deliver in the order it is sent. Data in TCP is read as a stream, where one packet ends, and another begins. Example of TCP includes World Wide Web, file transfer protocol, e-mail, etc
UDP (User Datagram Protocol)
UDP is based on connectionless protocol. When you send data, there is no guarantee whether your transferred message will reach there without any leakage. The message you sent may not be in
the same order. Packets are transmitted individually
and are guaranteed to be whole if they arrive. Example for UDP are VOIP (Voice Over Internet Protocol) TFTP ( Trivial File Transfer Protocol),
65
Explain the difference between half-duplex and full-duplex?
Full duplex means that the communication can occur in both directions at the same time, while half-duplex means that the communication can happen in one direction at a time.
66
What are the conversion steps of data encapsulation?
Conversion steps of data encapsulation includes
• Layer one, two and Three (Application/presentation/session) : Alphanumeric input
from the user is converted into Data
• Layer Four (Transport): Data is converted into small segments
• Layer Five (Network): Data converted into packets or datagrams and Network header is added
• Layer Six (Data Link): Datagrams or packets are built into frames
• Layer Seven (Physical): Frames are converted into bits
67
What command do we give if router IOS is stuck?
Ctrl+Shift+F6 and X is the command we give if router IOS is stuck.
68
What is route poisoning?
Route poisoning is a technique of preventing a network from transmitting packets through a route that has become invalid.
69
What route entry will be assigned to dead or invalid route in case of RIP?
In the case of RIP table entry, 16 hops will be assigned to dead or invalid route making it unreachable.
70
What is APIPA?
Automatic private IP addressing (APIPA) is a feature mainly found in Microsoft operating systems. APIPA enables clients to still communicate with other computers on the same network segment until an IP address can be obtained from a DHCP server, allowing the machine to fully participate on the network. The range of these IP address are the 169.254.0.1 to 169.254.255.254 with a default Class B subnet mask of 255.255.0.0.
71
What are the LMHOSTS files?
The LMHOSTS file is a static method of resolving NetBIOS names to IP addresses in the same way that the HOSTS file is a static method of resolving domain names into IP addresses. An LMHOSTS file is a text file that maps NetBIOS names to IP addresses; it must be manually configured and updated.
72
What is DHCP scope?
A scope is a range, or pool, of IP addresses that can be leased to DHCP clients on a given subnet.
73
What is FQDN?
An FQDN contains (fully qualified domain name) both the hostname and a domain name. It uniquely identifies a host within a DNS hierarchy.
74
What is the DNS forwarder?
DNS servers often must communicate with DNS servers outside of the local network. A forwarder is an entry that is used when a DNS server receives DNS
queries that it cannot resolve locally. It then forwards those requests to external DNS servers for resolution.
75
Which command will you use to find out the name of the pc in networks?
NSLOOKUP [192.168.0.1]
| Ip of target computer
76
How will enable sound service in 2003?
By default this service remain disable to enable this service
Start ==> administrative tools ==> service ==> windows audio ==> start up
type ==> automatic
77
How will enable CD burning service in 2003?
By default this service remain disable to enable this service
Start ==> administrative tools ==> service ==> IMAPI CD burning com
service ==> start up type ==> automatic
78
Define Network?
A network is a set of devices connected by physical media links. A network is recursively is a connection of two or more nodes by a physical link or two or more networks connected by one or more nodes.
79
What is a Link?
At the lowest level, a network can consist of two or more computers directly connected by some physical medium such as coaxial cable or optical fiber. Such a physical medium is called as Link.
80
What is a node?
A network can consist of two or more computers directly connected by some physical medium such as coaxial cable or optical fiber. Such a physical medium is called as Links and the computer it connects is called as Nodes.
81
What is a gateway or Router?
A node that is connected to two or more networks is commonly called as router or Gateway. It generally forwards message from one network to another.
82
What is point-point link?
If the physical links are limited to a pair of nodes it is said to be point-point link.
83
What is Multiple Access?
If the physical links are shared by more than two nodes, it is said to be Multiple Access.
84
What are the advantages of Distributed Processing?
a. Security/Encapsulation
b. Distributed database
c. Faster Problem solving
d. Security through redundancy
e. Collaborative Processing
85
What are the criteria necessary for an effective and efficient network?
a. Performance
It can be measured in many ways, including transmit time and response time.
b. Reliability
It is measured by frequency of failure, the time it takes a link to recover from a failure, and the network's robustness.
c. Security
Security issues includes protecting data from unauthorized access and viruses.
86
Name the factors that affect the performance of the network?
a. Number of Users
b. Type of transmission medium
c. Hardware
d. Software
87
Name the factors that affect the reliability of the network?
a. Frequency of failure
| b. Recovery time of a network after a failure
88
Name the factors that affect the security of the network?
a. Unauthorized Access
| b. Viruses
89
What is Protocol?
A protocol is a set of rules that govern all aspects of information communication.
90
What are the key elements of protocols?
The key elements of protocols are
a. Syntax
It refers to the structure or format of the data, that is the order in which they are presented.
b. Semantics
It refers to the meaning of each section of bits.
c. Timing
Timing refers to two characteristics: When data should be sent and how fast they can be sent.
91
What are the key design issues of a computer Network?
a. Connectivity
b. Cost-effective Resource Sharing
c. Support for common Services
d. Performance
92
Define Bandwidth and Latency?
Network performance is measured in Bandwidth (throughput) and Latency (Delay).
Bandwidth of a network is given by the number of bits that can be transmitted over the network in a certain period of time.
Latency corresponds to how long it takes a message to travel from one end off a network to the other. It is strictly measured in terms of time.
93
What is a peer-peer process?
The processes on each machine that communicate at a given layer are called peer-peer process.
94
When a switch is said to be congested?
It is possible that a switch receives packets faster than the shared link can accommodate and stores in its memory, for an extended period of time, then the switch will eventually run out of buffer space, and some packets will have to be dropped and in this state is said to congested state.
95
What is semantic gap?
Defining a useful channel involves both understanding the applications requirements and recognizing the limitations of the underlying technology. The gap between what applications expects and what the underlying technology can provide is called semantic gap.
96
What is Round Trip Time?
The duration of time it takes to send a message from one end of a network to the other and back, is called RTT.
97
Define the terms Unicasting, Multicasting and Broadcasting?
If the message is sent from a source to a single destination node, it is called Unicasting.
If the message is sent to some subset of other nodes, it is called Multicasting.
If the message is sent to all the m nodes in the network it is called Broadcasting.
98
What is Multiplexing?
Multiplexing is the set of techniques that allows the simultaneous transmission of multiple signals across a single data link.
99
Name the categories of Multiplexing?
a. Frequency Division Multiplexing (FDM)
b. Time Division Multiplexing (TDM)
i. Synchronous TDM
ii. ASynchronous TDM Or Statistical TDM.
c. Wave Division Multiplexing (WDM)
100
What is FDM?
FDM is an analog technique that can be applied when the bandwidth of a link is greater than the combined bandwidths of the signals to be transmitted.
101
What is WDM?
WDM is conceptually the same as FDM, except that the multiplexing and demultiplexing involve light signals transmitted through fiber optics channel.
102
What is TDM?
TDM is a digital process that can be applied when the data rate capacity of the transmission medium is greater than the data rate required by the sending
and receiving devices.
103
What is Synchronous TDM?
In STDM, the multiplexer allocates exactly the same time slot to each device at all times, whether or not a device has anything to transmit.
104
List the layers of OSI
a. Physical Layer
b. Data Link Layer
c. Network Layer
d. Transport Layer
e. Session Layer
f. Presentation Layer
g. Application Layer
105
Which layers are network support layers?
a. Physical Layer
b. Data link Layer and
c. Network Layers
106
Which layers are user support layers?
a. Session Layer
b. Presentation Layer and
c. Application Layer
107
Which layer links the network support layers and user support layers?
The Transport layer links the network support layers and user support layers.
108
What are the concerns of the Physical Layer?
```
Physical layer coordinates the functions required to transmit a bit stream over
a physical medium.
a. Physical characteristics of interfaces and media
b. Representation of bits
c. Data rate
d. Synchronization of bits
e. Line configuration
f. Physical topology
g. Transmission mode
```
109
What are the responsibilities of Data Link Layer?
The Data Link Layer transforms the physical layer, a raw transmission facility, to a reliable link and is responsible for node-node delivery.
a. Framing
b. Physical Addressing
c. Flow Control
d. Error Control
e. Access Control
110
What are the responsibilities of Network Layer?
The Network Layer is responsible for the source-to-destination delivery of packet possibly across multiple networks (links).
a. Logical Addressing
b. Routing
111
What are the responsibilities of Transport Layer?
The Transport Layer is responsible for source-to-destination delivery of the entire message.
a. Service-point Addressing
b. Segmentation and reassembly
c. Connection Control
d. Flow Control
e. Error Control
112
What are the responsibilities of Session Layer?
The Session layer is the network dialog Controller. It establishes, maintains and synchronizes the interaction between the communicating systems.
a. Dialog control
b. Synchronization
113
What are the responsibilities of Presentation Layer?
The Presentation layer is concerned with the syntax and semantics of the information exchanged between two systems.
a. Translation
b. Encryption
c. Compression
114
What are the responsibilities of Application Layer?
The Application Layer enables the user, whether human or software, to access the network. It provides user interfaces and support for services such as email, shared database management and other types of distributed information services.
a. Network virtual Terminal
b. File transfer, access and Management (FTAM)
c. Mail services
d. Directory Services
115
What are the two classes of hardware building blocks?
Nodes and Links.
116
What are the different link types used to build a computer network?
a. Cables
b. Leased Lines
c. Last-Mile Links
d. Wireless Links
117
What are the categories of Transmission media?
a. Guided Media
i. Twisted - Pair cable
1. Shielded TP
2. Unshielded TP
ii. Coaxial Cable
iii. Fiber-optic cable
b. Unguided Media
i. Terrestrial microwave
ii. Satellite Communication
118
What are the types of errors?
a. Single-Bit error
In a single-bit error, only one bit in the data unit has changed.
b. Burst Error
A Burst error means that two or more bits in the data have changed.
119
What is Error Detection? What are its methods?
Data can be corrupted during transmission. For reliable communication errors must be deducted and Corrected. Error Detection uses the concept of
redundancy, which means adding extra bits for detecting errors at the destination. The common Error Detection methods are
a. Vertical Redundancy Check (VRC)
b. Longitudinal Redundancy Check (VRC)
c. Cyclic Redundancy Check (VRC)
d. Checksum
120
What is Redundancy?
The concept of including extra information in the transmission solely for the purpose of comparison. This technique is called redundancy.
121
What is VRC?
It is the most common and least expensive mechanism for Error Detection. In VRC, a parity bit is added to every data unit so that the total number of 1s becomes even for even parity. It can detect all single-bit errors. It can detect burst errors only if the total number of errors in each data unit is odd.
122
What is LRC?
In LRC, a block of bits is divided into rows and a redundant row of bits is added to the whole block. It can detect burst errors. If two bits in one data unit
are damaged and bits in exactly the same positions in another data unit are also damaged, the LRC checker will not detect an error. In LRC a redundant data unit follows n data units.
123
What is CRC?
CRC, is the most powerful of the redundancy checking techniques, is based on binary division.
124
What is Checksum?
Checksum is used by the higher layer protocols (TCP/IP) for error detection.
