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Typical SOHO Ethernet LANs
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A Small Office / Home Office (SOHO) LAN today uses only Ethernet LAN technology. First, the LAN needs a device called an Ethernet LAN switch, which provides many physical ports into which cables can be connected. An Ethernet technology uses Ethernet cables, which is a general reference to any cable that conforms to any of several Ethernet standards.
The LAN uses Ethernet cables to connect different Ethernet devices or nodes to one of the switch’s Ethernet ports.
Picture1 shows a model of a SOHO Ethernet LAN. The picture shows a single LAN switch, five cables, and five other Ethernet nodes: three PCs, a printer, and one network device called a router.
(The router connects the LAN to the WAN, in this case to the Internet.)
Picture 1. Typical Small Ethernet-Only SOHO LAN
Although Picture 1 shows a simple Ethernet LAN, many SOHO Ethernet LANs today combine the router and switch into a single device. Vendors sell consumer-grade integrated networking devices that work as a router and Ethernet switch, as well as doing other functions. These devices typically have “router” on the packaging, but many models also have four-port or eight-port Ethernet LAN switch ports built into the device.
SOHO wireless LANs
Typical SOHO LANs today also support wireless LAN connections. Ethernet defines wired LAN technology only; in other words, Ethernet LANs use cables. However, you can build one LAN that uses both Ethernet LAN technology as well as wireless LAN technology. Wireless LANs use radio waves to send the bits from one node to the next.
Most wireless LANs rely on another networking device: a wireless LAN access point (AP). The AP acts somewhat like an Ethernet switch, in that all the wireless LAN nodes communicate with the Ethernet switch by sending and receiving data with the wireless AP. Of course, as a wireless device, the AP does not need Ethernet ports for cables, other than for a single Ethernet link to connect the AP
to the Ethernet LAN. Most SOHO networks today would use a single device, often labeled as a “wireless router” that does all these functions.
Typical Enterprise LANs
Enterprise networks have similar needs compared to a SOHO network, but on a much larger scale. For example, enterprise Ethernet LANs begin with LAN switches installed in a wiring closet behind a locked door on each floor of a building. The electricians install the Ethernet cabling from that wiring closet to rooms where devices might need to connect to the LAN. At the same time, most enterprises also support wireless LANs in the same space, to allow people to move around and still work and to support a growing number of devices that do not have an Ethernet LAN interface.
Picture 2 shows a conceptual view of a typical enterprise LAN in a three-story building. Each floor has an Ethernet LAN switch and a wireless LAN AP. To allow communication between floors, each per-floor switch connects to one centralized distribution switch. For example, PC3 can send data to PC2, but it would first flow through switch SW3 to the first floor to the distribution switch (SWD) and then back up through switch SW2 on the second floor.
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Picture 2 also shows the typical way to connect a LAN to a WAN using a router. LAN switches and wireless access points work to create the LAN itself. Routers connect to both the LAN and the WAN. To connect to the LAN, the router simply uses an Ethernet LAN interface and an Ethernet cable, as shown on the lower right of Picture 2.
Practical work № 7
1. Find the English equivalents to the following phrases in the given text:
1) Для передачи битов с одного узла на другой;
2) Сетевой коммутатор с пятью или восемью портами;
3) Сетевые устройства потребительского класса;
4) Соединять близлежащие устройства;
5) Физические и канальные уровни;
6) Коммутатор сети;
7) Использовать кабели для каналов связи между узлами;
8) Встроенный коммутатор;
9) Разъёмы на концах кабеля;
10) Передающая данные с одного устройства на другое;
11) Интегрированные сетевые устройства;
12) Маршрутизатор и коммутатор объединены в одно устройство;
13) Множество портов для подключения кабелей;
14) Не использовать ни проводов, ни кабелей;
15) Сети необходимо такое устройство, как свич;
16) Семейство стандартов локальных сетей;
17) Точка доступа действует наподобие коммутатора;
18) Типичный способ подключения сети LAN к сети WAN с использованием маршрутизатора;
19) Корпоративные сети;
20) Поэтажный коммутатор;
21) Позволяя сотрудникам свободно перемещаться;
22) В гораздо большем масштабе;
23) За закрытыми дверцами;
24) Обычно именуемый, как «беспроводной маршрутизатор»
25) Монтажники прокладывают кабель.
2. Answer the questions:
1) What are main types of networks?
2) What are general types of LANs?
3) What is a wired LAN?
4) What is a wireless LAN?
5) What does a SOHO Ethernet LAN need to function well?
6) What device does a wireless LAN need?
7) Look at Picture 2: how can PC3 send data to PC2?
Thank you!
Criteria of marks:
30-32 points – “excellent”
23-29 points – “good”
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16-22 points – “satisfactory”
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