Before starting to configure a router, you should first understand its structure and configuration content.
processor
Like other computers, a router running a 10S also contains a "central processor" (CPU). The CPUs of different series and models are also different. The router's processor is responsible for performing the work required to process data packets, such as maintaining various tables required for routing and bridging, and making routing decisions. The speed at which a router processes packets depends largely on the type of processor.
Memory
All computers have some forms of memory installed. There are four main types of routers:
Read-only memory (ROM).
flash memory.
Random access memory (RAM).
Nonvolatile RAM (NVRAM).
Of all types of memory, RAM is the only memory that will lose its contents when the router starts or powers apart;
In the following introduction, we will briefly explain the main uses of each memory of the router.
The ROM saves the router's boot (start) software. This is the first software run by the router, responsible for getting the router to work normally. Some routers save a complete set of IOS in ROM so that when another IOS cannot be used. For emergency use. The ROM is usually made on one or more chips and soldered to the motherboard of the router.
The main purpose of flash memory is to save 10S software and maintain the normal operation of the router. If the router has flash memory installed, it is the default location of the 10S software used to boot the router. As long as the flash memory capacity is sufficient, multiple IOS images can be saved to provide multiple boot options. Flash memory is either made on the SIMM of the motherboard or made into a PCMCIA card.
RAM has a wide range of functions and cannot be listed here. But there are two things worth mentioning, namely IOS system tables and buffering. IOS meets all its regular storage needs through RAM.
The main function of NVRAM is to save the configuration data read by the IOS when the router is started. This configuration is called "Startup Configuration".
interface
All routers have an "interface". In the previous section, we have listed some of the interface types supported by the router. In routers that use I0S, each interface has its own name and number. The full name of an interface is composed of its type identifier and at least one number. Numbering starts from zero.
For routers whose interfaces have been fixed, or which use modular interfaces, and which can only be changed by shutting down the host, there is only one number in the full name of the interface, and they are numbered according to their physical order in the router. For example, Ethernet0 is the name of the first Ethernet interface; while Serial2 is the name of the third serial port.
If the router supports "online insertion and deletion", or has the ability to dynamically change the configuration of the physical interface (hot swapping of the card), then the full name of an interface should contain at least two numbers, separated by a forward slash (/). Among them, the first number represents the slot number, and the interface processor card will be installed on this slot; the second number represents the port number of the interface processor. For example, in a 7507 router, Ethernet5/0 represents the first Ethernet interface located on slot 5 - assuming that slot 5 is connected to an Ethernet interface processor card.
Some routers also support "universal interface processor" (VIP). A certain interface name on a VIP consists of three numbers, and is also separated by a forward slash (/). The interface number is in the form of "Slot/Port Adapter/Port". For example, Ethemet4/0/1 refers to the second Ethernet interface of the first port adapter on slot 4.
When you first come into contact with these numbering methods, you may feel a little confused. But don't worry, there are ways to let the router tell us the full name of all its interfaces.
Console Port
Almost all routers have a console port installed behind the router. The console port provides an EIA/TIA-232 (formerly known as RS-232) asynchronous serial interface, allowing us to communicate with the router. As for which form of physical connection is established with the console port, it depends on the model of the router. Some routers use a DB25 female connection (DB25F), while others use an RJ45 connector. Typically, smaller routers use RJ45 console connectors, while larger routers use DB25 console connectors.
Auxiliary port
Most Cisco routers are equipped with an Auxiliary Port. It is similar to the console turbulent port, providing an EIA/TIA-232 asynchronous serial connection, allowing us to communicate with the router. Auxiliary ports are usually used to connect to Modem to enable remote management of routers. Remote communication links are usually not used to transmit usually routed packets. Its main function is to access a router after the network path or loop fails.
Configuration File
There are two types of 10S configurations:
1) Run the configuration.
2) Start configuration.
Both are displayed in ASCII text format. Therefore, we can read and operate it very easily. A router can only choose one of these two types.
Run the configuration
Sometimes called "active configuration", it resides in RAM and contains I0S configuration commands currently "active" in the router. When configuring 10S, it is equivalent to changing the router's running configuration.
Start the configuration
The startup configuration resides in NVRAM and contains configuration commands you want to execute when the router starts. After startup is completed, the command in startup configuration becomes "Run configuration".
Sometimes the startup configuration is also called a "backup configuration". This is because after modifying and acknowledging the running configuration, the running configuration should usually be copied to NVRAM and the changes made should be "backed up" so that the router can be called the next time the router starts up.
process
The so-called I0S "process" refers to a special software task running on a router that is used to implement a certain function. For example, the routing of an IP packet is done by one process; while the routing of an AppleTalk packet is done by another process.
Other examples of I0S processes are such as routing protocols and memory allocation routines. When we place the command in the configuration file to configure the 10S, it is actually equivalent to controlling the behavior of each process that constitutes the 10S. All of these processes run simultaneously on the router. As for the number and type of processes that can run on a router, it depends on the speed of the router CPU and the installed RAM capacity. As can be seen, this is similar to the number of programs running on a PC depends on the type of CPU and the RAM capacity equipped. Article entry: csh Editor in charge: csh
processor
Like other computers, a router running a 10S also contains a "central processor" (CPU). The CPUs of different series and models are also different. The router's processor is responsible for performing the work required to process data packets, such as maintaining various tables required for routing and bridging, and making routing decisions. The speed at which a router processes packets depends largely on the type of processor.
Memory
All computers have some forms of memory installed. There are four main types of routers:
Read-only memory (ROM).
flash memory.
Random access memory (RAM).
Nonvolatile RAM (NVRAM).
Of all types of memory, RAM is the only memory that will lose its contents when the router starts or powers apart;
In the following introduction, we will briefly explain the main uses of each memory of the router.
The ROM saves the router's boot (start) software. This is the first software run by the router, responsible for getting the router to work normally. Some routers save a complete set of IOS in ROM so that when another IOS cannot be used. For emergency use. The ROM is usually made on one or more chips and soldered to the motherboard of the router.
The main purpose of flash memory is to save 10S software and maintain the normal operation of the router. If the router has flash memory installed, it is the default location of the 10S software used to boot the router. As long as the flash memory capacity is sufficient, multiple IOS images can be saved to provide multiple boot options. Flash memory is either made on the SIMM of the motherboard or made into a PCMCIA card.
RAM has a wide range of functions and cannot be listed here. But there are two things worth mentioning, namely IOS system tables and buffering. IOS meets all its regular storage needs through RAM.
The main function of NVRAM is to save the configuration data read by the IOS when the router is started. This configuration is called "Startup Configuration".
interface
All routers have an "interface". In the previous section, we have listed some of the interface types supported by the router. In routers that use I0S, each interface has its own name and number. The full name of an interface is composed of its type identifier and at least one number. Numbering starts from zero.
For routers whose interfaces have been fixed, or which use modular interfaces, and which can only be changed by shutting down the host, there is only one number in the full name of the interface, and they are numbered according to their physical order in the router. For example, Ethernet0 is the name of the first Ethernet interface; while Serial2 is the name of the third serial port.
If the router supports "online insertion and deletion", or has the ability to dynamically change the configuration of the physical interface (hot swapping of the card), then the full name of an interface should contain at least two numbers, separated by a forward slash (/). Among them, the first number represents the slot number, and the interface processor card will be installed on this slot; the second number represents the port number of the interface processor. For example, in a 7507 router, Ethernet5/0 represents the first Ethernet interface located on slot 5 - assuming that slot 5 is connected to an Ethernet interface processor card.
Some routers also support "universal interface processor" (VIP). A certain interface name on a VIP consists of three numbers, and is also separated by a forward slash (/). The interface number is in the form of "Slot/Port Adapter/Port". For example, Ethemet4/0/1 refers to the second Ethernet interface of the first port adapter on slot 4.
When you first come into contact with these numbering methods, you may feel a little confused. But don't worry, there are ways to let the router tell us the full name of all its interfaces.
Console Port
Almost all routers have a console port installed behind the router. The console port provides an EIA/TIA-232 (formerly known as RS-232) asynchronous serial interface, allowing us to communicate with the router. As for which form of physical connection is established with the console port, it depends on the model of the router. Some routers use a DB25 female connection (DB25F), while others use an RJ45 connector. Typically, smaller routers use RJ45 console connectors, while larger routers use DB25 console connectors.
Auxiliary port
Most Cisco routers are equipped with an Auxiliary Port. It is similar to the console turbulent port, providing an EIA/TIA-232 asynchronous serial connection, allowing us to communicate with the router. Auxiliary ports are usually used to connect to Modem to enable remote management of routers. Remote communication links are usually not used to transmit usually routed packets. Its main function is to access a router after the network path or loop fails.
Configuration File
There are two types of 10S configurations:
1) Run the configuration.
2) Start configuration.
Both are displayed in ASCII text format. Therefore, we can read and operate it very easily. A router can only choose one of these two types.
Run the configuration
Sometimes called "active configuration", it resides in RAM and contains I0S configuration commands currently "active" in the router. When configuring 10S, it is equivalent to changing the router's running configuration.
Start the configuration
The startup configuration resides in NVRAM and contains configuration commands you want to execute when the router starts. After startup is completed, the command in startup configuration becomes "Run configuration".
Sometimes the startup configuration is also called a "backup configuration". This is because after modifying and acknowledging the running configuration, the running configuration should usually be copied to NVRAM and the changes made should be "backed up" so that the router can be called the next time the router starts up.
process
The so-called I0S "process" refers to a special software task running on a router that is used to implement a certain function. For example, the routing of an IP packet is done by one process; while the routing of an AppleTalk packet is done by another process.
Other examples of I0S processes are such as routing protocols and memory allocation routines. When we place the command in the configuration file to configure the 10S, it is actually equivalent to controlling the behavior of each process that constitutes the 10S. All of these processes run simultaneously on the router. As for the number and type of processes that can run on a router, it depends on the speed of the router CPU and the installed RAM capacity. As can be seen, this is similar to the number of programs running on a PC depends on the type of CPU and the RAM capacity equipped. Article entry: csh Editor in charge: csh