Networking & CCNA
Networking & CCNA
Networking & CCNA
Kartei Details
| Karten | 80 |
|---|---|
| Sprache | Deutsch |
| Kategorie | Informatik |
| Stufe | Universität |
| Erstellt / Aktualisiert | 25.09.2021 / 21.06.2025 |
| Weblink |
https://card2brain.ch/cards/20210925_networking_ccna
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List at least two functions of intermediary devices.
- Regenerate and retransmit communication signals
- Maintain information about what pathways exist through the network and internetwork
- Notify other devices of errors and communication failures
- Direct data along alternate pathways when there is a link failure
- classify and direct message according to priorities
- Permit or deny the flow of data, based on seurity settings
List the intermediary device categories.
- Wireless Router
- Lan Switch
- Router
- Multilayer Switch
- Firewall Appliance
List at least two criteria for choosing a network media type.
- What is the maximum distance that the media can successfully carry a signal?
- What is the environment in which the media will be installed?
- That is the amount of data and at what speed must it be transmitted?
- What is the cost of the media and installation?
Explain the difference between a LAN and a WAN. Give examples of each
The two most common types of network infrastructures are Local Area Networks (LANs), and Wide Area Networks (WANs). A LAN is a network infrastructure that provides access to users and end devices in a small geographical area. A LAN is typically used in a department within an enterprise, a home, or a small business network. A WAN is a network infrastructure that provides access to other networks over a wide geographical area, which is typically owned and managed by a larger corporation or a telecommunications service provider
A LAN is a network infrastructure that spans a small geographical area. LANs have specific characteristics:
- LANs interconnect end devices in a limited area such as a home, school, office building, or campus.
- A LAN is usually administered by a single organization or individual. Administrative control is enforced at the network level and governs the security and access control policies.
- LANs provide high-speed bandwidth to internal end devices and intermediary devices, as shown in the figure.
WANs
The figure shows a WAN which interconnects two LANs. A WAN is a network infrastructure that spans a wide geographical area. WANs are typically managed by service providers (SPs) or Internet Service Providers (ISPs).
WANs have specific characteristics:
- WANs interconnect LANs over wide geographical areas such as between cities, states, provinces, countries, or continents.
- WANs are usually administered by multiple service providers.
- WANs typically provide slower speed links between LANs.
What are some of the common ways a home user connects to the internet?
- Cable - Typically offered by cable television service providers, the internet data signal transmits on the same cable that delivers cable television. It provides a high bandwidth, high availability, and an always-on connection to the internet.
- DSL - Digital Subscriber Lines also provide high bandwidth, high availability, and an always-on connection to the internet. DSL runs over a telephone line. In general, small office and home office users connect using Asymmetrical DSL (ADSL), which means that the download speed is faster than the upload speed.
- Cellular - Cellular internet access uses a cell phone network to connect. Wherever you can get a cellular signal, you can get cellular internet access. Performance is limited by the capabilities of the phone and the cell tower to which it is connected.
- Satellite - The availability of satellite internet access is a benefit in those areas that would otherwise have no internet connectivity at all. Satellite dishes require a clear line of sight to the satellite.
- Dial-up Telephone - An inexpensive option that uses any phone line and a modem. The low bandwidth provided by a dial-up modem connection is not sufficient for large data transfer, although it is useful for mobile access while traveling.
What are some common methods that businesses use to connect to the internet in your area?
- Dedicated Leased Line - Leased lines are reserved circuits within the service provider’s network that connect geographically separated offices for private voice and/or data networking. The circuits are rented at a monthly or yearly rate.
- Metro Ethernet - This is sometimes known as Ethernet WAN. In this module, we will refer to it as Metro Ethernet. Metro ethernets extend LAN access technology into the WAN. Ethernet is a LAN technology you will learn about in a later module.
- Business DSL - Business DSL is available in various formats. A popular choice is Symmetric Digital Subscriber Line (SDSL) which is similar to the consumer version of DSL but provides uploads and downloads at the same high speeds.
- Satellite - Satellite service can provide a connection when a wired solution is not available
4 basic characteristics that network architects must address to meet user expectations:
- Fault Tolerance
- Scalability
- Quality of Service (QoS)
- Security
Types of clouds
Public clouds
Cloud-based applications and services offered in a public cloud are made available to the general population. Services may be free or are offered on a pay-per-use model, such as paying for online storage. The public cloud uses the internet to provide services.
Private clouds
Cloud-based applications and services offered in a private cloud are intended for a specific organization or entity, such as a government. A private cloud can be set up using the organization’s private network, though this can be expensive to build and maintain. A private cloud can also be managed by an outside organization with strict access security.
Hybrid clouds
A hybrid cloud is made up of two or more clouds (example: part private, part public), where each part remains a distinct object, but both are connected using a single architecture. Individuals on a hybrid cloud would be able to have degrees of access to various services based on user access rights.
Community clouds
A community cloud is created for exclusive use by specific entities or organizations. The differences between public clouds and community clouds are the functional needs that have been customized for the community. For example, healthcare organizations must remain compliant with policies and laws (e.g., HIPAA) that require special authentication and confidentiality. Community clouds are used by multiple organizations that have similar needs and concerns. Community clouds are similar to a public cloud environment, but with set levels of security, privacy, and even regulatory compliance of a private cloud.
common external threats to networks:
- Viruses, worms, and Trojan horses - These contain malicious software or code running on a user device.
- Spyware and adware - These are types of software which are installed on a user’s device. The software then secretly collects information about the user.
- Zero-day attacks - Also called zero-hour attacks, these occur on the first day that a vulnerability becomes known.
- Threat actor attacks - A malicious person attacks user devices or network resources.
- Denial of service attacks - These attacks slow or crash applications and processes on a network device.
- Data interception and theft - This attack captures private information from an organization’s network.
- Identity theft - This attack steals the login credentials of a user in order to access private data.
basic security components for a home or small office network:
- Antivirus and antispyware - These applications help to protect end devices from becoming infected with malicious software.
- Firewall filtering - Firewall filtering blocks unauthorized access into and out of the network. This may include a host-based firewall system that prevents unauthorized access to the end device, or a basic filtering service on the home router to prevent unauthorized access from the outside world into the network.
The physical layer standards address three functional areas:
- Physical Components
- Encoding
- Signaling
Fiber-optic cables are broadly classified into two types:
- Single-mode fiber (SMF)
- Multimode fiber (MMF)
Fiber-optic cabling is now being used in four types of industry:
- Enterprise Networks - Used for backbone cabling applications and interconnecting infrastructure devices
- Fiber-to-the-Home (FTTH) - Used to provide always-on broadband services to homes and small businesses
- Long-Haul Networks - Used by service providers to connect countries and cities
- Submarine Cable Networks - Used to provide reliable high-speed, high-capacity solutions capable of surviving in harsh undersea environments at up to transoceanic distances. Search the internet for “submarine cables telegeography map” to view various maps online.
A PC that is communicating with a web server has a TCP window size of 6,000 bytes when sending data and a packet size of 1,500 bytes. Which byte of information will the web server acknowledge after it has received four packets of data from the PC?
Which scenario describes a function provided by the transport layer?
Which three layers of the OSI model provide similar network services to those provided by the application layer of the TCP/IP model? (Choose three.)
A client creates a packet to send to a server. The client is requesting SMTP service. What number will be used as the destination port number in the sending packet?
Which three statements describe a DHCP Discover message? (Choose three.)
Explanation: When a host configured to use DHCP powers up on a network it sends a DHCPDISCOVER message. FF-FF-FF-FF-FF-FF is the L2 broadcast address. A DHCP server replies with a unicast DHCPOFFER message back to the host.
Which three protocols operate at the application layer of the TCP/IP model? (Choose three.)
FTP, DHCP, and POP3 are application layer protocols. TCP and UDP are transport layer protocols. ARP is a network layer protocol.
Which layer in the TCP/IP model is used for formatting, compressing, and encrypting data?
The application layer of the TCP/IP model performs the functions of three layers of the OSI model – application, presentation, and session. The application layer of the TCP/IP model is the layer that provides the interface between the applications, is responsible for formatting, compressing, and encrypting data, and is used to create and maintain dialogs between source and destination applications.
What is the function of the HTTP GET message?
Explanation: There are three common HTTP message types: GET – used by clients to request data from the web server POST – used by clients to upload data to a web server PUT – used by clients to upload data to a web server
Which two protocols may devices use in the application process that sends email? (Choose two.)
POP, POP3, and IMAP are protocols that are used toretrieve email from servers. SMTP is the default protocol that is used tosend email. DNS may be used by the sender email server to find theaddress of the destination email server
What are two characteristics of peer-to-peer networks? (Choose two.)
Peer-to-peer networks have decentralized resources because every computer can serve as both a server and a client. One computer might assume the role of server for one transaction while acting as a client for another transaction. Peer-to-peer networks can share resources among network devices without the use of a dedicated server.
Which application layer protocol uses message types such as GET, PUT, and POST?
The GET command is a client request for data from a web server. A PUT command uploads resources and content, such as images, to a web server. A POST command uploads data files to a web server.
What is true about the Server Message Block protocol?
The Server Message Block protocol is a protocol for file, printer, and directory sharing. Clients establish a long term connection to servers and when the connection is active, the resources can be accessed. Every SMB message has the same format. The use of SMB differs from FTP mainly in the length of the sessions. SMB messages can authenticate sessions.
What is an advantage of SMB over FTP?
SMB and FTP are client/server protocols that are used for file transfer. SMB allows the connecting device to access resources as if they were on the local client device. SMB and FTP use the TCP protocol for connection establishment and they can transfer data in both directions. FTP requires two connections between the client and the server, one for commands and replies, the other for the actual file transfer.
What is an example of network communication that uses the client-server model?
When a user types a domain name of a website into the address bar of a web browser, a workstation needs to send a DNS request to the DNS server for the name resolution process. This request is a client/server model application. The eMule application is P2P. Sharing a printer on a workstation is a peer-to-peer network. Using ARP is just a broadcast message sent by a host.
Which protocol is used by a client to communicate securely with a web server?
HTTPS is a secure form of HTTP used to access web content hosted by a web server.
Which applications or services allow hosts to act as client and server at the same time?
P2P applications allow the clients to behave as servers if needed. When using authentication services, email exchange, and client/server applications, one host acts as server and the other acts as client at all times.
Which OSI layer provides the interface between the applications used to communicate and the underlying network over which messages are transmitted?
The application layer is the layer that is closest to the end user and provides the interface between the underlying network and the applications used to communicate.
What is a common protocol that is used with peer-to-peer applications such as WireShare, Bearshare, and Shareaza?
The Gnutella protocol is used when one user shares an entire file with another user. A person would load a Gnutella-based application such as gtk-gnutella or WireShare and use that application to locate and access resources shared by others.
Why does HTTP use TCP as the transport layer protocol?
When a host requests a web page, transmission reliability and completeness must be guaranteed. Therefore, HTTP uses TCP as its transport layer protocol.
Which field in the TCP header indicates the status of the three-way handshake process?
The value in the control bits field of theTCP header indicates the progress and status of the connection.
Which two types of applications are best suited for UDP? (Choose two.)
Applications that can tolerate some data loss, require a simple request and reply, and handle reliability themselves are best suited for UDP. UDP has low overhead and no requirement of reliability. TCP provides services for reliability, controlling data flow, and the reordering of segments.
A client application needs to terminate a TCP communication session with a server. Place the termination process steps in the order that they will occur. (Not all options are used.)
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In order to terminate a TCP session, the client sends to the server a segment with the FIN flag set. The server acknowledges the client by sending a segment with the ACK flag set. The server sends a FIN to the client to terminate the server to client session. The client acknowledges the termination by sending a segment with the ACK flag set.In order to terminate a TCP session, the client sends to the server a segment with the FIN flag set. The server acknowledges the client by sending a segment with the ACK flag set. The server sends a FIN to the client to terminate the server to client session. The client acknowledges the termination by sending a segment with the ACK flag set.In order to terminate a TCP session, the client sends to the server a segment with the FIN flag set. The server acknowledges the client by sending a segment with the ACK flag set. The server sends a FIN to the client to terminate the server to client session. The client acknowledges the termination by sending a segment with the ACK flag set.
In what two situations would UDP be better than TCP as the preferred transport protocol? (Choose two.)
UDP is a very simple transport layer protocol that does not guarantee delivery. Devices on both ends of the conversation are not required to keep track of the conversation. UDP is used as the transport protocol for applications that need a speedy, best-effort delivery.
What does a client do when it has UDP datagrams to send?
When a client has UDP datagrams to send, it just sends the datagrams.
Which two fields are included in the TCP header but not in the UDP header? (Choose two.)
The sequence number and window fields are included in the TCP header but not in the UDP header.
Which protocol or service uses UDP for a client-to-server communication and TCP for server-to-server communication?
Some applications may use both TCP and UDP. DNS uses UDP when clients send requests to a DNS server, and TCP when two DNS serves directly communicate.
Which flag in the TCP header is used in response to a received FIN in order to terminate connectivity between two network devices?
In a TCP session, when a device has no more data to send, it will send a segment with the FIN flag set. The connected device that receives the segment will respond with an ACK to acknowledge that segment. The device that sent the ACK will then send a FIN message to close the connection it has with the other device. The sending of the FIN should be followed with the receipt of an ACK from the other device.
