Router interfaces and connections (figure)

The network location of a vro is complex. It can be an internal subnet edge or an internal or external network edge. At the same time, to achieve strong applicability, it needs to connect to a variety of networks, so that its interfaces must be diverse. Not to mention network enthusiasts, but many network administrators cannot make it clear. To this end, I would like to introduce all kinds of interfaces and Connection Methods of routers.

Quick Introduction

Interface

Page 1 LAN interface page 2 WAN Interface page 3 router configuration interface

Connection

Page 4 connection between routers and LAN access devices page 5 connection between routers and Internet access devices page 6 Configure port connection mode
I. router interface

A vro has powerful network connection and routing functions. It can be physically connected to a variety of different networks, which makes the router interface technology very complex, the more upscale a router has more interface types, because the more network types it can connect. Vro ports include LAN ports, WAN ports, and configuration ports.

1. LAN interface

Common Ethernet interfaces include AuI, BNC and RJ-45 interfaces, as well as FDDI, ATM, Gigabit Ethernet and so on all have corresponding network interfaces, the following describes the main LAN interfaces.

(1). AuI Port
The AuI port is the interface used to connect to the coarse coaxial cable. It is a "d" Type 15-pin interface, this is one of the most common ports in the ring or bus network. The router can connect to the 10base-5 network through a coarse coaxial cable transceiver. But more is the use of external transceiver (AUI-to-RJ-45), to achieve the connection with the 10base-t Ethernet. Of course, you can also use other types of transceiver to connect to a fine coaxial cable (10base-2) or optical cable (10base-f. AUI interface 1.

(2). RJ-45 Port
RJ-45 port is our most common port, it is our common twisted pair Ethernet port. Because in Fast Ethernet also mainly uses twisted pair as transmission medium, according to the port communication rate of different RJ-45 port can be divided into 10base-t network RJ-45 port and 100base-tx network RJ-45 port two types. Among them, the RJ-45 port of the 10base-t network is usually identified as "eth" in the router, while the RJ-45 port of the 100base-tx network is usually identified as "10/100 BTX ".

Figure 2

Figure 3

2 shows the 10base-t network RJ-45 port, and 3 shows the 10/100 BASE-TX network RJ-45 port. In fact, the two kinds of RJ-45 port is completely the same as the port itself, but the corresponding network circuit structure in the port is different, so it cannot be casually connected.

(3). SC Port
The SC port is also known as an optical fiber port. It is used to connect to the optical fiber. An optical fiber port is usually used to connect to a vswitch with an optical fiber port, instead of directly connecting to a workstation using a optical fiber. Instead, it is connected to a vswitch with a optical fiber port, such as a fast Ethernet or Gigabit Ethernet. These ports are generally available in high-end routers and are marked with "B FX", as shown in figure 4.

2. WAN Interface

As mentioned above, vrouters can not only achieve the connection between the LAN, but also the connection between the LAN and the Wan, and between the WAN. However, because the wide area network is large and the network environment is complex, the speed requirement of the port used by the router to connect to the wide area network is very high. In Ethernet, the speed requirement is generally above Mbps Fast Ethernet. The following describes several common Wan interfaces.

(1). RJ-45 Port
The RJ-45 port can also be used to establish a connection between the Wan and the lan vlan (Virtual LAN), as well as to the remote network or the Internet. If you use a router to provide routes for different VLANs, you can directly connect to different VLAN ports using twisted pair wires. But pay attention to here the RJ-45 port connected to the network is generally not very can be 10base-t this, generally is more than Mbps Fast Ethernet. If you need to connect to a remote network through optical fiber, or connect to other types of ports, you need to use the transceiver to connect to each other. 5 is the fast Ethernet port.

(2). AuI Port
We have also discussed the AuI port in the LAN. It is a network interface used to connect to the coarse coaxial cable. In fact, the AuI port is also commonly used to connect to the WAN, however, this type of interface is rarely used in the WAN. On Cisco 2600 series routers, two WAN connection ports (6) for AuI and RJ-45 are provided, allowing you to select the appropriate type as needed.

Figure 6

(3). High-Speed Synchronous Serial Port
In the WAN connection of the router, the port with the most applications must be counted as "high-speed synchronous serial port", as shown in 7.

Figure 7

This port is mainly used to connect to network connection modes such as DDN, frame relay, X.25, and PSTN. Sometimes DDN or X.25 or other WAN connection technologies are used for leased line connection between enterprise networks. This type of synchronization port generally requires a very high speed, because in general, both ends of the network connected through this port require real-time synchronization.

(4) asynchronous serial port
Asynchronous Serial Port (async) is mainly used for modem or modem pool connections, as shown in figure 8. It is mainly used to enable remote computers to dial in to the network through the public telephone network. Compared with the synchronous port described above, this asynchronous port requires much less speed, because it does not require real-time synchronization between the two ends of the network, but must be continuous, this is mainly because the communication speed of this interface is low.

(5). isdn bri Port
Because the connection speed of the Internet access method such as ISDN has its own unique side, at that time, when ISDN was just emerging, it had been fully applied to the Internet connection mode. The isdn bri port is used to connect an ISDN line to the Internet or other remote networks through a router, achieving a communication rate of kbps. ISDN has two speed connection ports: isdn bri (Basic Rate Interface) and isdn pri (basic group rate interface ). The isdn bri port is a RJ-45 standard and is connected to the ISDN nt1 using a RJ-45-to-RJ-45 Express Line. The bri shown in Figure 9 is the isdn bri port.

Figure 9

3. router configuration interface

The configuration ports of the vro are "console" and "Aux". The "console" is usually used for basic configuration of the vro through a dedicated connection with the computer, "Aux" is used for vro remote configuration and connection.

1. Console Port
The Console port uses a dedicated connection to directly connect to the computer's serial port, and uses the terminal simulation program (such as the "Super Terminal" in Windows) for local configuration of the router. The Console port on the router is mostly a RJ-45 port. As shown in figure 10, a console Configuration Port is included.

2. Aux port
The Aux port is an asynchronous port. It is mainly used for remote configuration, dial-up, and modem connection. The Aux port and Console port are usually provided at the same time because they are used differently. For the interface illustration, see Figure 10 above.

Figure 10

Ii. vro hardware connection

As mentioned above, there are many vro interface types, which are used for different network connections. If you cannot understand the functions of the respective ports, you are likely to make wrong connections, the network connection is incorrect and the network is disconnected. Next we will further understand the connection application environment of various ports through several vro Network Connection forms. Because of the port type, the hardware connection of the router is mainly divided into three types: the connection to the LAN device, the connection to the WAN device, and the connection to the configuration device.

1. connections between routers and LAN Access Devices

A lan device is primarily a hub and a switch. A switch typically uses only RJ-45 and SC ports, while a hub typically uses AuI, BNC, and RJ-45 ports. Next, we will briefly introduce how to connect a vro and a set of ports on the devices.

(1). RJ-45-to-RJ-45
This connection means that the router is connected to both ends of the RJ-45 interface, if the router and the Set line equipment provide RJ-45 port, then, you can use twisted pair wires to connect the two ports of the cabling device and the router. Note that, unlike the connection between a set-line device, the connection between a router and a set-line device does not use a cross line, but uses a direct line. That is to say, the line sequence at both ends of the Jumper is identical, it does not mean that the line sequence is the same, but it is best not to use the one-to-one matching method. Note that the cascade connections between hub devices are usually performed through cascade ports, while the interconnection between routers and hubs or switches is performed through common ports.

In addition, the communication rate between the router and the port of the Set-line equipment should be matched as much as possible. Otherwise, it is better to make the port speed of the Set-line equipment higher than the Router speed and connect the router directly to the switch.

(2). AUI-to-RJ-45
This problem occurs when the router is connected to the hub. If the router only owns the AuI port, and the pooled device provides the RJ-45 port, you must use the AUI-to-RJ-45 transceiver to connect the two. Of course, the twisted pair jumper between the transceiver and the Collector must also use a straight line, as shown in connection 11.

(3). SC-to-RJ-45 or SC-to-AuI
This is generally the connection between the router and the switch, such as the switch only has the fiber port, and the routing device provides the RJ-45 port or AuI port, the connection between the two can be achieved only through the SC-to-RJ-45 or SC-to-AuI transceiver. The twisted pair jumper between the transceiver and the switch must also use a straight line. However, it is rare that a vswitch is a pure fiber interface.

Figure 11

2. connection between a router and an Internet access device

The main applications of routers are Internet connections. The connection between routers and Internet access devices is as follows:

(1). asynchronous serial port connection
Asynchronous serial ports are mainly used to establish connections with the modem to enable remote computers to dial in to the local area network through the public telephone network. In addition, it can be used to connect to other terminals. When the router is connected to the modem through a cable, it must be connected using a AYSNC-to-DB25 or AYSNC-to-DB9 adapter. The connection between the router and the modem or terminal is shown in Figure 12.

(2). Synchronous Serial Port
There are many synchronous serial port types supported in the vro. For example, the Cisco system can support five different types of synchronous serial ports: EIA/TIA-232 interface, EIA/TIA-449 interface, V.35 interface, X.21 serial cable integration and EIA-530 interface, the corresponding adapter icons are 13, 14, 15, 16, and 17, respectively. However, note that the two ends of the adapter are generally different shapes (generally referred to as the "public" header at one end of the adapter with a pin and so on ", while the adapter end with a hole is usually called "mother", note that the "EIA-530" interface at both ends are the same interface type), this is mainly considering the close connection. In the figure, the "Public Header" is the DTE (data terminal device, data terminal equipment) connection adapter, and the "Master Header" below is the DCE (data communication device, data communications equipment) connection adapter. As shown in Figure 18, the synchronous serial port is connected to the Internet access device. During the connection, you only need to check the connection line and the interface type of the device to know the correct choice.

(3). isdn bri Port
The isdn bri module of a Cisco router can be divided into two types: one is the isdn bri s/T module and the other is the isdn bri u module, the former must be integrated with the nt1 terminal device of ISDN to connect to the Internet, because the S/T port can only be connected to a digital phone device and is not applicable to the current situation, however, after nt1, you can connect to an existing analog phone device, as shown in Figure 19. The latter has a built-in nt1 module, which we call as an "nt1 +" terminal device. Its "U" port can be directly connected to the analog telephone external line. Therefore, there is no need to connect to the external ISDN nt1, you can directly connect to the wall panel socket of the telephone line, as shown in Figure 20.

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