Router Interface Details

Vro Network
The location 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 also 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.
　　I. router interface


A vro has powerful network connection and routing functions. It can be physically connected to a variety of different networks, which determines the router interface technology.
The more complicated the router, the more interface types it can connect to, 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. Vro accessible
The coarse coaxial cable transceiver is connected to the 10base-5 network. However, it is more with the help of external transceiver (AUI-to-RJ-45), to achieve

Network connection. 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.
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(2). RJ-45 Port
RJ-45 port is our most common port, it is our common twisted pair Ethernet port. Because twisted pair wires are used as transmission media in fast Ethernet, the communication speed based on the port is not
The same RJ-45 port can be divided into 10base-t network RJ-45 port and 100base-tx network RJ-45 port two types. Among them, 10base-t network RJ-45
The port is typically identified as eth in the router, while the RJ-45 port of the 100base-tx network is typically identified as 10/100 BTX ".
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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.
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(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.
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2. WAN Interface


As mentioned above, routers can not only achieve connection between LAN, but also more important applications.
It also lies in the connection between the LAN and WAN, and between the WAN and 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 WAN and lan vlan (Virtual LAN), as well as with the remote network or
Internet connection. If you use a router to provide routes for different VLANs, you can directly connect to different VLAN ports using twisted pair wires. But note that the RJ-45 port here is connected

Generally, 10base-t is not applicable to the network. Generally, it is over Mbps Fast Ethernet. If you must connect to a remote network through optical fiber or connect to another port type
You must use a transceiver to connect to each other. 5 is the fast Ethernet port.
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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 the Cisco 2600 series router, two WAN connection ports (6) for AuI and RJ-45 are provided for the user
You can select an appropriate type based on your needs.
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(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.
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This port is mainly used to connect DDN, Frame
Relay), X.25, PSTN (analog telephone line) and other network connection modes. Sometimes DDN or X.25 or other WAN connection technologies are used for leased line connection between enterprise networks. This synchronous Port
Generally, the speed is very high, because the two 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 implement remote computers
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.
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(5). isdn bri Port
Because of the Internet such as ISDN
Connect
The connection speed of the inbound mode has its own unique side. Therefore, at the time of the emergence of ISDN, it had been fully applied to the connection mode of the Internet. ISDN
The 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, one
It is isdn bri (Basic Rate Interface), and the other is isdn pri (basic group rate interface ). The isdn bri port is based on the RJ-45 standard, with ISDN
The nt1 connection uses a RJ-45-to-RJ-45 Express Line. The bri shown in Figure 9 is the isdn bri port.
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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 is connected directly to the serial port of the computer using a dedicated connection, and the terminal simulation program (such as Windows
Local configuration of the vro. The Console port on the router is mostly a RJ-45 port. As shown in figure 10, a console Configuration Port is included.
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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.
　　Ii. vro hardware connection


As mentioned above, there are many vro interface types, which are used separately.
Network connection. If you cannot understand the role of the respective ports, it is likely to make a wrong connection, resulting in incorrect network connection and network failure. Next we will further understand several network connection forms of the router.
Connect to the application environment with various ports. 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 set Line Equipment
Both provide RJ-45 ports, then you can use twisted pair wires to connect the two ports of the collector and router together. Note that the connection is different from that between a set-line device.

The connection uses a straight line instead of a cross line. That is to say, the line sequence at both ends of the Jumper is the same, but it does not mean that the line sequence is the same, but it is best not to adopt a one-to-one matching method. Note that the Hub
Cascade connections between 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.
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(3). SC-to-RJ-45 or SC-to-AuI
This is generally the connection between a vro and a vswitch. For example, a vswitch only has a fiber port while
The RJ-45 port or AuI port is provided by the device, and the connection between the two must be achieved through a SC-to-RJ-45 or SC-to-AuI transceiver. Transceiver and switch settings
The twisted pair jumpers between the slave and slave must also use a straight line. However, it is rare that a vswitch is a pure fiber interface.
　　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. AYSNC-to-DB2 is required when the router is connected to the modem through a cable
5 or AYSNC-to-DB9 adapter to connect. The connection between the router and the modem or terminal is shown in Figure 12.
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(2). Synchronous Serial Port
Many synchronous serial port types are supported in routers, such as Cisco
Just
Supports five different types of synchronous serial ports: EIA/TIA-232 interface,
EIA/TIA-449 interface, V.35 interface, X.21 serial cable assembly and EIA-530 interface, the corresponding adapter diagram 13, fig 14, fig 15, fig 16, fig
17. However, it should be noted that, because the two ends of the adapter connection generally use different shapes (generally referred to as the "public" end of the adapter with a plug-in and so on, and the adaptation with Holes
Device end is usually called the "parent", note that the "EIA-530" interface at both ends are the same interface type), this is mainly considering the close connection. The "Public Header" in the figure is DTE (Data
Final
End device, data terminal equipment) connection adapter, the "master" Below is 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.
You can know the correct choice.
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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 the ISDN
To connect to the Internet, because the S/T port can only connect to the digital phone device, not the current situation, but can connect to the existing analog phone device through nt1
Figure 19 shows the connection. The latter is called "nt1" because of the built-in nt1 module.
"Terminal device, its" U "port can be directly connected to the analog phone external line, so you do not need to connect to the external ISDN nt1, you can directly connect to the telephone line wall panel socket, as shown in 20.
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　　3. Configure the port connection mode

As mentioned above, the configuration ports of the vro vary according to the configuration method, and the ports used are different. There are two main types of ports, one is the "console" port used for local configuration, and the other is the "Aux" port used for remote configuration. The following describes the connection methods respectively.
(1). Connection Method of the Console Port
When you use a computer to configure a router, you must use the flip line to connect the Console port of the router to the serial port of the computer.
/Parallel port connection together, this connection line generally needs to be specially crafted, according to the computer end is the serial port or parallel port, choose to make RJ-45-to-DB-9 or RJ-45-to-DB-
25. Use an adapter for conversion, as shown in Figure 21.
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(2). Aux port connection method
When you need to configure the vro through remote access, you need to use the Aux port. Aux actually
As mentioned above, the interface structure is the same as the RJ-45, but the corresponding circuit is different, the function is also different, according to the port used by the modem is different, to determine through the Aux port and
Modem must also be connected by RJ-45 to DB9 or RJ-45
Db25 transceiver selection. The Connection Method 22 between the Aux port of the router and the modem is shown in.
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