Router port introduction?

After understanding the basic knowledge of routers, we began to formally intervene in the use of routers from this article. This paper will introduce the basic work before use-the hardware connection of the router.

Because the router belongs to a kind of high-grade network access equipment used for interconnection between networks, because of its connection

The connected networks may be different, so there are many types of interfaces. Therefore, before formally introducing the connection mode of the router, it is necessary for us to know some basic interfaces of the router.

I. Router interface

Routers have very powerful network connection and routing functions, which can physically connect various networks, which determines that the interface technology of routers is very complicated. The more high-end routers, the more types of interfaces there are. Routers can not only connect different LAN segments, but also connect different types of WAN, so the interface types of routers can generally be divided into two types: LAN interface and WAN interface. In addition, because the router itself has no input and terminal display equipment, but it needs necessary configuration to be used normally, so the general router has a control port "console" for connecting computers or terminal equipment, and the router is configured through specific software. Let's first look at the LAN and WAN connection ports of the router.

1. LAN interface

According to the names of their interfaces, we can see that these interfaces are mainly used to connect routers and LANs. Because the types of LAN are also various, it also determines that the types of LAN interfaces of routers may be diverse. Different networks have different interface types. Common Ethernet interfaces mainly include AUI, BNC and RJ-45 interfaces, as well as FDDI, ATM and optical fiber interfaces. These networks have corresponding network interfaces. The following are the main LAN interfaces.

(1) AUI port

AUI port is used to connect thick coaxial cable. It is a "D" type 15 pin interface, and it is one of the more common ports in token ring network or bus network. Routers can connect with 10Base-5 network through thick coaxial cable transceiver, but more often they connect with 10Base-T Ethernet through external transceivers (AUI to RJ-45). Of course, the connection with thin coaxial cable (10Base-2) or optical cable (10Base-F) can also be realized by other types of transceivers. The AUI interface of the router mentioned here is mainly used for network connection with thick coaxial cable as transmission medium. The diagram of AUI interface is shown in figure 1.

Figure 1

(2)RJ-45 Port

RJ-45 port is our most common port, and it is also our common twisted-pair Ethernet port. Because twisted pair is mainly used as the transmission medium in fast Ethernet, RJ-45 ports can be divided into two types according to the different communication rates of ports: RJ-45 port in 10Base-T network and RJ-45 port in 100Base-TX network. Among them, the RJ-45 port of 10Base-T network is usually marked as "ETH" in routers, while the RJ-45 port of 100Base-TX network is usually marked as "1100btx", which is mainly due to the rapid development of Ethernet at present. As shown in the left figure of Figure 2, it is the RJ-45 port of 10Base-T network, and the right figure is the RJ-45 port of1100base-TX network. In fact, these two RJ-45 ports are exactly the same as the ports themselves, but the corresponding network circuit structures in the ports are different and cannot be connected casually.

Figure 2

(3)SC port

SC port, also called optical fiber port, is used to connect optical fibers. Generally speaking, this kind of optical fiber port is unlikely to be directly connected to the workstation through optical fiber, and generally connected to switches with optical fiber ports such as fast Ethernet or Gigabit Ethernet through optical fiber. This port is generally only available in high-end routers, and it is marked with "100b FX", as shown in Figure 3.

Figure 3

2. WAN interface

As mentioned above, routers can not only realize the connection between LANs, but also realize the interconnection between LANs and WANs, WANs and WANs. However, due to the large-scale WAN and complex network environment, the ports used by routers to connect WAN are very fast. In Ethernet, the general requirement is 100Mbps fast Ethernet. The following describes several common WAN interfaces.

(1)RJ-45 Port

RJ-45 port can also be used to establish the connection between VLAN and WAN and LAN, as well as the connection with remote network or Internet. If you use a router to route different VLANs, you can directly connect to different VLAN ports through twisted pair. It should be noted, however, that the RJ-45 port here is generally not connected to 10Base-T, but to a fast Ethernet network above 100Mbps. If you have to connect to a remote network through optical fiber, or to other types of ports, you need to use a transceiver to realize the connection between them. As shown in Figure 4, it is a fast Ethernet port.

Figure 4

(2)AUI Port

We also talked about AUI port in LAN, which is a network interface for connecting thick coaxial cable. In fact, AUI port is also commonly used to connect WAN, but this type of interface is rarely used in WAN. On Cisco 2600 series routers, two WAN connection ports, AUI and RJ-45, are provided, and users can choose the appropriate type according to their own needs, as shown in Figure 5.

Figure 5

(3) high-speed synchronous serial port

In the WAN connection of routers, the most commonly used port is the "high-speed synchronous serial port", which is mainly used to connect DDN, Frame Relay, X.25, PSTN and other widely used network connection methods. Enterprise networks are sometimes connected by dedicated lines through WAN connection technologies such as DDN or X.25 This synchronous port generally requires very high speed, because generally speaking, both ends of the network connected through this port require real-time synchronization. As shown in Figure 6, it is a high-speed synchronous serial port.

Figure 6

(4) Asynchronous serial port

Asynchronous serial port (ASYNC) is mainly used to connect modems or modem pools, and remote computers can dial into the network through public telephone network. Compared with the synchronous port mentioned above, the speed requirement of this asynchronous port is much looser, because it does not need to keep real-time synchronization between the two ends of the network, but only needs to be continuous. So what we see when surfing the internet is not necessarily the real-time content on the website, but it is not important, because after all, this delay is very small, and it is important to keep the webpage downloaded normally when browsing the webpage. As shown in Figure 7, it is an asynchronous serial port.

Figure 7

(5)ISDN BRI port

Because of its unique connection speed, ISDN, an Internet access method, has been fully applied in the Internet connection mode when ISDN just emerged. ISDN BRI port is used to connect ISDN lines to the Internet or other remote networks through routers, which can realize the communication rate of 128Kbps. ISDN has two rate connection ports, one is ISDN BRI (Basic Rate Interface) and the other is ISDN PRI (Basic Group Rate Interface). ISDN BRI port adopts RJ-45 standard, and the connection with ISDN NT 1 adopts RJ-45 to RJ-45 direct dial line. As shown in Figure 8, this is an ISDN BRI port.

Figure 8

3. Router Configuration Interface

There are actually two configuration ports on the router, namely "console" and "AUX". The "console" is usually used to connect with the computer through a private line when the router is basically configured, while the "auxiliary" is used for the remote configuration and connection of the router.

(1) console port

The console port is directly connected to the serial port of the computer with a dedicated connection, and the router is configured locally with a terminal emulation program (such as HyperTerminal under Windows). The console ports of routers are mostly RJ-45 ports. Figure 9 contains a console configuration port.

Figure 9

(2) Auxiliary port

AUX port is an asynchronous port, which is mainly used for remote configuration, dial-up connection and connection with modem through transceiver. Support hardware flow control. Auxiliary ports and console ports are usually placed together because their respective configuration environments are different. Still referring to Figure 9 above.