Networking & CCNA

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• Wireless Router
• Lan Switch
• Router
• Multilayer Switch
• Firewall Appliance

• 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?

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.

• 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.

• 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

• Fault Tolerance
• Scalability
• Quality of Service (QoS)
• Security

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.

• 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.

• 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.

• Physical Components
• Encoding
• Signaling

• Single-mode fiber (SMF)
• Multimode fiber (MMF)

• 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.