Lesson 22 Flashcards
What do the terms “interface,” “protocol,” and “service” mean in relation to computer networks?
An interface is any channel through which network data can flow. Hardware network interfaces are defined by physical network connections, and virtual network interfaces are logical network connections that ride on top of hardware network connections.
A protocol is a set of rules used to describe a specific type of network communication. Protocols are necessary for separate network devices to communicate properly. Finally, a network service (as it pertains to Network preferences) is the collection of settings that define a network connection.
What’s the purpose of Internet Protocol v4 (IPv4) addresses and subnet masks?
The Internet Protocol (IP) address identifies the location of a specific network device. IP addresses are the primary identification used by the Internet protocol suite TCP/IP for both local area and wide area networks. Subnet masks are used by network devices to identify their local network range and to determine whether outgoing data is destined for a network device on the LAN.
How does IPv4 addressing differ from IPv6 addressing?
Most common IP addresses and subnet masks share the same IPv4 formatting. An IPv4 address is a 32-bit number represented in four groups of three-digit numbers, known as octets, separated by periods. Each octet has a value between 0 and 255. An IPv6 address is a 128-bit number that’s presented in eight groups of four-digit hexadecimal numbers separated by colons. This allows for a huge range of addresses, and as a result IPv6 addressing essentially includes subnet information.
How does the IP use the MAC address to send messages between computers on a local area network (LAN)?
If a network device needs to send data to another network device on the same LAN, it addresses the outgoing packets based on the destination device’s MAC address.
How does the IP transfer messages between computers over a wide area network (WAN)?
A network client uses the subnet mask to determine whether the destination IP address is on the LAN. If the destination IP address isn’t on the LAN, it’s assumed the destination address is on another network, and the client sends the data to the IP address of the local network router. The network router then sends the data, via a WAN connection, on to another router that it thinks is closer to the destination. This continues across WAN connections from router to router until the data reaches its destination.
How is the Domain Name Service (DNS) used to facilitate network naming?
The DNS service is used to translate host names to IP addresses via forward lookups and translate IP addresses to host names via reverse lookups. DNS is architected as a hierarchy of worldwide domain servers. Local DNS servers provide name resolution and possibly host names for local clients. These local DNS servers connect to DNS servers higher in the DNS hierarchy to resolve both unknown host names and host local domain names.
What’s used to identify a Wi-Fi network?
A Service Set Identifier, or SSID, is used to identify a Wi-Fi network name and associated configuration.
What Wi-Fi authentication protocols are supported by OS X?
OS X supports authenticated Wi-Fi via the following authentication protocols: WEP, WPA/WPA2 Personal, and WPA/ WPA2 Enterprise, which includes support for 802.1X authentication.
How can an OS X system automatically connect to a Wi-Fi network?
A new OS X system can only automatically connect to Wi-Fi networks that have no standard authentication mechanism, otherwise known as an “open network.” However, a configured OS X system can automatically reconnect to authenticated Wi-Fi networks, provided that the appropriate information was saved to the Keychain system.
Through what mechanism can a standard user configure Wi- Fi settings?
A standard user can connect to any non-WPA Enterprise Wi-Fi network via the Wi-Fi status menu. Because the system Keychain must be modified for WPA Enterprise connections, only an administrative user can establish these types of connections.
