对于当今所有的现代设备，某些术语可能会非常混乱。几乎每个人都听说过路由器这个词，但它实际上是什么意思呢？您的路由器只是路由器，还是也可以是交换机、接入点和网关？
过去，上述每个术语通常指的是执行单一功能的单一设备。这些天不再是这样了。来自ISP(ISP)的“调制解调器”可能是调制解调器、路由器、交换机和接入点的一体。正如我稍后会解释的那样，您不一定想要一个一体式设备，尽管有些ISP(ISPs)会以这种方式推动您。
在本文中，我将尝试解释这些术语背后的概念，而不会过于技术化。首先(First)，我将讨论交换机和集线器之间的区别，因为这两种设备属于同一类别。接下来，我们将讨论路由器以及它们与交换机和集线器不同的原因。最后，我们将讨论调制解调器和其他网络术语，如接入点和网关。
交换机与集线器
集线器是一种过时的设备，这些天您永远都不想购买。它看起来就像一个开关，但内部的工作方式不同。您使用以太网(Ethernet)电缆将设备连接到集线器，并且从设备发送到集线器的任何信号都简单地在连接到集线器的所有其他端口上重复输出。
集线器被视为第 1 层(Layer 1)（物理(Physical)）设备，而交换机被放入第 2 层(Layer 2)（数据链路(Data Link)）。这就是集线器和交换机的不同之处。OSI模型的数据链路(Data Link)层处理MAC地址，交换机在处理端口上的传入帧时会查看MAC地址。(MAC)
帧是一种数据类型，用于在所有网络设备上传输数据。不要担心技术细节，只要知道它包含帧内的源和目标MAC地址以及源和目标 IP 地址。(MAC)包含源/目标 IP 地址的帧部分称为数据包。
交换机不会盲目地将它在一个端口上接收到的所有帧转发到设备上的所有其他端口，而是会创建一个MAC地址源表，然后将帧转发到具有正确目标MAC地址的端口。这显着减少了网络上的流量，因为两个设备之间存在直接通信，而不是一对多类型的通信。
使用集线器，连接到集线器的设备越多，网络上的冲突就越多。冲突是指两台计算机或设备同时发送数据并且信号在到达目的地之前发生物理冲突。这种情况经常发生在集线器上，因为每个端口上的所有流量都会重复到所有其他端口。
使用交换机，冲突为零，因为只有正在通信的两个设备将来回发送数据。带宽不与其他端口共享。
这也是为什么集线器是半双工设备而交换机是全双工设备的原因。集线器上的设备越多，必须共享的带宽就越多，因此网络变得更慢。使用交换机，带宽不必共享，所有端口都全速运行。
路由器与调制解调器
路由器工作在OSI模型的(OSI)第 3 层(Layer 3)（网络(Network)），它处理 IP 地址。MAC(Whereas MAC)地址用于将帧从一台设备移动到另一台直接连接的设备，而 IP 地址用于通过Internet路由数据包。
路由器是将网络连接在一起并在它们之间路由流量的设备。在家里，这通常意味着您的路由器将您的内部本地网络连接到您的ISP的网络。这可以通过多种方式完成。路由器可以在一端（ISP）连接到调制解调器，在另一端（本地网络）连接到交换机。如果您有一个组合调制解调器/路由器设备，那么一端将连接到您的ISP，而另一端将连接到交换机（如果使用以太网(Ethernet)） ，或者只是WiFi（如果设备也支持）。
上面(Above)是典型的仅路由器设备（从技术上讲，它是上面的无线路由器）。Internet端口将连接到您的调制解调器，其余端口是交换机端口。路由器几乎总是内置有交换机。调制解调器将使用电话线（用于DSL）、电缆连接或光纤（ONT ）连接到您的(ONT)ISP。
以上(Above)是典型的电缆调制解调器。它有一个同轴端口，用于连接来自ISP的电缆，还有一个以太网(Ethernet)端口，您可以将其插入路由器上的Internet端口。如果可能，最好为调制解调器和路由器配备两个不同的设备。
无线路由器仅允许您与您可能拥有的任何无线设备共享有线连接。如今，大多数路由器都是无线路由器，还包括几个有线端口。
无线路由器(Wireless Router)与无线接入点(Wireless Access Point)
现在让我们谈谈无线路由器与无线接入点。无线接入点是一种允许无线设备通过在两个网络之间桥接流量来连接到现有有线网络的设备。这两个术语之所以如此混乱，是因为无线路由器基本上是路由器和无线接入点的结合体。
但是，无线接入点不能是无线路由器。独立的无线接入点将有一条以太网(Ethernet)电缆连接到路由器，并将有线信号转换为无线信号。它不会像典型的路由器那样将数据包从本地网络路由到另一个网络或Internet 。
无线接入(Wireless Access)点通常用于企业或大型公共场所，它们需要将许多无线站全部连接在一起以形成一个网络。无线(Wireless)路由器通常也内置防火墙，而无线AP(APs)则没有。
其他网络术语
您将听到的其他非常常见的术语之一是Default Gateway。那么默认网关是什么？它基本上是将您的本地网络连接到外部世界的设备。通常，这是本地网络上的最后一个路由器。
在家庭网络中，默认网关很可能是您的无线路由器，因为每当您需要与网络外的设备通信时，路由器就是连接到调制解调器的设备。请注意，要与本地网络上的其他设备通信，您不需要默认网关。默认(Default)网关仅在与远程网络（即Internet ）通信时使用。
希望这能解开所有这些网络术语背后的一些谜团。这是一个简单的概述，但足以让您向其他人解释它。享受！
Router vs Switch vs Hub vs Modem vs Access Point vs Gateway
With all of today’s modern devices, some of the terminology can be quite confuѕing. Pretty much everyone has heard of the term router, but what does it actually mean? Is your router just a router or can іt also be a switсh, an access point and a gatеwаy?
Back in the days, each term above usually referred to a single device that performed a single function. That is no longer true these days. Your “modem” from your ISP is probably a modem, router, switch and access point all-in-one. You don’t necessarily want an all-in-one device as I’ll explain later, though some ISPs push you that way.
In this article, I’ll try to explain the concept behind each of these terms without getting too technical. First, I’ll talk about the difference between switches and hubs, as both of those devices are in the same category. Next, we’ll talk about routers and why they are different than switches and hubs. Finally, we’ll talk about modems and other networking terms like access points and gateways.
Switches vs Hubs
A hub is an obsolete device that you would never want to buy these days. It looks just like a switch, but works differently on the inside. You connect devices to a hub using Ethernet cable and any signal sent from a device to the hub is simply repeated out on all other ports connected to the hub.
Hubs are considered Layer 1 (Physical) devices whereas switches are put into Layer 2 (Data Link). This is where hubs and switches differ. The Data Link layer of the OSI model deals with MAC addresses and switches look at MAC addresses when they process an incoming frame on a port.
A frame is a data type that is used to carry data on all networking devices. Don’t worry about the technical details, just know that it contains source and destination MAC addresses and source and destination IP addresses inside the frame. The part of the frame that contains the source/destination IP addresses is called a packet.
Instead of blindly forwarding all the frames it receives on one port to all the other ports on the device, a switch will create a MAC address source table and then forward the frame to the port with the correct destination MAC address. This significantly reduces the amount of traffic on the network because there is direct communication between the two devices rather than a one-to-all type of communication.
With hubs, the more devices you connect to the hub, the more collisions there will be on the network. Collisions means when two computers or devices send data at the same time and the signals physically collide before reaching the destination. This happens on hubs a lot because all the traffic coming in on each port is repeated out to all the other ports.
With switches, there are zero collisions because only the two devices that are communicating will be sending data back and forth. The bandwidth is not shared with other ports.
This is also why a hub is a half-duplex device whereas a switch is a full-duplex device. The more devices on a hub, the more bandwidth that has to be shared and therefore the network gets slower. With switches, the bandwidth does not have to be shared and all ports operate at full speed.
Router vs Modem
Routers work at Layer 3 (Network) of the OSI model, which deals with IP addresses. Whereas MAC addresses are used to move frames from one device to another directly connected device, IP addresses are used to route packets across the Internet.
A router is a device that joins networks together and routes traffic between them. At home, this typically means you router connect your internal local network to your ISP’s network. This can be done in several ways. A router can be connected to your modem on one end (ISP) and to a switch on the other end (local network). If you have a combo modem/router device, then one end will connect to your ISP and the other will be either to a switch if using Ethernet or will simply be WiFi, if the device supports that too.
Above is a typical router only device (technically, it’s a wireless router above). The Internet port will connect to your modem and the rest of the ports are switch ports. A router pretty much always has a switch built-in. A modem will connect to your ISP using phone line (for DSL), cable connection or fiber (ONT).
Above is a typical cable modem. It has a single coaxial port for the cable connection coming in from your ISP and a single Ethernet port that you could plug into the Internet port on your router. If possible, it’s always best to have two different devices for your modem and router.
A wireless router simply allows you to share the wired connection with any wireless devices you may have. Most routers these days are wireless routers that include several wired ports also.
Wireless Router vs Wireless Access Point
Now let’s talk about wireless routers vs wireless access points. A wireless access point is a device that allows wireless devices to connect to an existing wired network by bridging traffic between the two networks. The reason why these two terms are so confusing is that a wireless router is basically a router and a wireless access point combined.
However, a wireless access point cannot be a wireless router. A stand-alone wireless access point will have an Ethernet cable running to the router and convert the wired signal into a wireless one. It will not route packets from the local network to anther network or the Internet like a typical router.
Wireless Access Points are typically used by businesses or in big public spaces where they need many wireless stations all connected together to form one network. Wireless routers typically have firewalls built-in too, while wireless APs do not.
Other Networking Terms
One of the other very common terms you will hear is Default Gateway. So what is the default gateway? It’s basically the device that connects your local network to the outside world. Typically, this is the last router on your local network.
On a home network, the default gateway will most likely be your wireless router because anytime you need to communicate with a device outside your network, the router is the device that is connected to your modem. Note that to communicate with other devices on your local network, you do not need a default gateway. Default gateways are only used when communicating with remote networks, i.e. the Internet.
Hopefully, this clears up some of the mystery behind all of these networking terms. It’s a simplistic overview, but enough that you can explain it to someone else. Enjoy!
