220-1201 Networking Study Guide for the CompTIA A+ Core Series Exam

Small Office/Home Office (SOHO) Networks

A SOHO network is a LAN used to create connections between devices, commonly a combination of both wired and wireless connections, enabling access to shared resources such as an internet connection or a printer. Creation of a SOHO network also allows for centralization of network management and configuration of connected devices.

You must be able to install and configure basic wired and wireless SOHO networks. On the CompTIA A+ exam, these concepts will be addressed in scenario-based questions.

Internet Protocol (IP) Addressing

IP addressing is the assignment of a unique device identifier on a local network or the internet. The IP address is responsible for managing logical network addresses. While IP addressing is not unique to SOHO networks, understanding how IP addressing works is vital to properly configuring a SOHO network.

IPv4

An IPv4 address is a 32-bit hierarchical address that identifies a host on a network and is typically written in dotted-decimal notation. The 32-bit address is divided into four bytes, or octets, containing eight bits each (e.g., 192.168.10.55). IPv4 addresses are divided into designated classes—A, B, C, D, E, and F—based on the first three bits of the IP address. IPv4 addresses are finite and are running out.

Private Addresses

A private IP address is not routable on the internet. There are specific ranges for the different classes of private addresses:

• Class A private address range: 10.0.0.0–10.255.255.255
• Class B private address range: 172.16.0.0–172.31.255.255
• Class C private address range: 192.168.0.0.–192.168.255.255

Public Addresses

Public addresses are routable on the internet. Public addresses are purchased, and only one computer can hold any given public address at a time.

Subnet Mask

A subnet mask is a 32-bit number used to separate IPv4 addresses into a host portion and a network portion, which is integral to the routing process to direct traffic to the appropriate IP address. For example, a subnet mask of 255.255.255.0 indicates that the first three octets are the network portion of the IP address, while the final octet is the host portion.

IPv6

IPv6 addresses are 128-bit addresses expressed in hexadecimal notation and are composed of eight 16-bit fields separated by colons, such as 2001:0db8:3c4d:0012:0000:0000:1234:56ab (which can be reduced to 2001:db8:3c4d:12::1234:56ab).

Automatic Private IP Addressing (APIPA)

APIPA assigns an IP address to a device that was not assigned a static or dynamic IP address. The address will be in the 169.254.0.0 network. This is generally not useful, other than being an indication that the device failed to get an IP address through normal means. These addresses are also referred to as link-local addresses.

Static

A static address is one that is set manually by a user or administrator. A device that is assigned a static address will keep that address until someone changes the configuration.

Dynamic

A dynamic address is one that is automatically assigned, typically by a router or DHCP server. The next time a device that was dynamically assigned an IP address joins the network, it may be assigned a different IP address.

Gateway

A gateway is a router that connects your network to another network, typically the internet. When configuring a device on the network, you specify the internal IP address of the gateway as a default destination to send traffic.

Internet Connection and Network Types

For the CompTIA A+ exam, you should be able to compare and contrast different internet connection methods and network types.

Internet Connection Types

Internet connection types are methods, either wired or wireless, through which a device can connect to the internet.

Satellite

A satellite connection is a wireless connection type that employs the use of satellites to achieve connectivity. Satellite connections are typically slower than wired broadband connections and require a satellite dish. Weather and misalignment can affect connectivity.

Fiber

A fiber connection is a type of wired connection that uses a fiber-optic cable made of thin flexible glass or plastic fiber surrounded by a rubberized outer sheath to send data via light signals. Fiber offers fast data transmission. There are two types of fiber varieties: single-mode fiber (SMF) and multimode fiber (MMF).

Cable

A cable connection is a type of wired connection that uses a cable, either coaxial/coax or twisted pair, for data transmission. Coax and twisted pair cables use different connector types and cable specifications.

Digital Subscriber Line (DSL)

A DSL is a type of wired connection that uses existing phone lines paired with a DSL modem to provide internet service.

Cellular

A cellular connection is a type of wireless connection that uses a provider’s cellular network for connectivity.

Wireless Internet Service Provider (WISP)

A WISP is a wireless connection in which an internet service provider (ISP) offers connectivity using wireless technology. WISP connections are fixed point-to-point connections.

Network Types

Network types define the general area that is covered by a network.

Local Area Network (LAN)

A LAN is a collection of devices connected to one another in one physical area, such as an office building. They can be small or large.

Wide Area Network (WAN)

A WAN is a network that covers a large geographical area and is composed of multiple LANs. The internet is a WAN.

Personal Area Network (PAN)

A PAN is used to create a network between devices in a very small area and is commonly composed of Bluetooth-connected devices. For example, a connection between a mobile device and headphones or between a computer and a wireless mouse creates a PAN.

Metropolitan Area Network (MAN)

A MAN is a network larger than a LAN but smaller than a WAN and limited to a smaller geographical area, such as a city or a campus.

Storage Area Network (SAN)

A SAN is a network area composed of storage devices and is commonly used to provide low latency and high performance to critical applications. For example, a SAN can be used for databases or virtualized infrastructures.

Wireless Local Area Network (WLAN)

A WLAN is a LAN in which the connections are wireless rather than wired.