Cisco offers many different routers, which are suited for different networking environments, such as enterprise LANs, service provider WANs, and so on. The various models offer various features that are suitable for an array of different environments. However, the core function of a router is to route packets, and for that reason, all routers have many common components.
Cisco 提供多種不同的路由器，適用於不同的網路環境，例如企業 LAN、服務供應商 WAN 等。各種型號提供不同的功能，適合各種不同的環境。然而，路由器的核心功能是路由封包，因此，所有路由器都具備許多共同的元件。
These components are as follows:
這些元件如下：
- CPU: A CPU, or processor, is the chip installed on the motherboard that carries out the instructions of a computer program. For example, it processes all the information gathered from other routers or sent to other routers.CPU：CPU（處理器）是安裝在主機板上的晶片，負責執行電腦程式的指令。舉例來說，它會處理從其他路由器收集或傳送至其他路由器的所有資訊。
- Motherboard:The motherboard is the central circuit board, which holds critical electronic components of the system. The motherboard provides connections to other peripherals and interfaces.主機板：主機板是中央電路板，容納系統的關鍵電子元件。主機板提供與其他周邊裝置及介面的連接。
- Memory: There are four primary types of memory:記憶體：主要有四種類型的記憶體：
- RAM: RAM is memory on the motherboard that stores data during CPU processing. It is a volatile type of memory in that its information is lost when power is switched off. RAM provides temporary memory for the router's running configuration while the router is powered on.RAM：RAM 是主機板上的記憶體，於 CPU 處理期間儲存資料。它是一種揮發性記憶體，關閉電源後其中的資訊便會遺失。RAM 在路由器通電期間，為其執行中設定提供暫存記憶體。
- NVRAM:NVRAM retains content when the router is powered down. NVRAM stores the startup configuration file for most router platforms. It also contains the software configuration register, which determines which Cisco IOS image is used when booting the router.NVRAM：NVRAM 在路由器關閉電源後仍保留其內容。NVRAM 在大多數路由器平台上儲存啟動設定檔。它也包含軟體設定暫存器，用來決定開機時使用哪個 Cisco IOS 映像檔。
- ROM: ROM is read-only memory on the motherboard. The content of ROM is not lost when power is switched off. Data stored in ROM cannot be modified, or it can be modified only slowly or with difficulty. ROM sometimes contains a ROM monitor (ROMMON). ROM Monitor initializes the hardware and boots the Cisco IOS Software when you power on or reload a router. You can use the ROM monitor to perform certain configuration tasks, such as recovering a lost password or downloading software over the console port. ROM also includes bootloader software (bootstrap), which helps the router boot when it cannot find a valid Cisco IOS image in the flash memory. During normal startup, the ROM Monitor initializes the router, and then control passes to the Cisco IOS Software.ROM：ROM 是主機板上的唯讀記憶體。關閉電源後，ROM 的內容不會遺失。儲存在 ROM 中的資料無法修改，或只能緩慢或困難地修改。ROM 有時包含 ROM 監視器（ROMMON）。ROM 監視器會在你開機或重新載入路由器時，初始化硬體並啟動 Cisco IOS 軟體。你可以使用 ROM 監視器執行某些設定工作，例如復原遺失的密碼，或透過主控台埠下載軟體。ROM 也包含開機載入程式軟體（bootstrap），可在路由器於快閃記憶體中找不到有效的 Cisco IOS 映像檔時協助其開機。在正常啟動過程中，ROM 監視器會先初始化路由器，接著將控制權交給 Cisco IOS 軟體。
- Flash:Flash memory is nonvolatile storage that can be electrically erased and reprogrammed. Flash memory stores the Cisco IOS image. On some platforms, it can also store configuration files or boot images.快閃記憶體：快閃記憶體是一種非揮發性儲存裝置，可透過電子方式抹除並重新程式化。快閃記憶體儲存 Cisco IOS 映像檔。在某些平台上，它也可以儲存設定檔或開機映像檔。
- Ports (also referred to as interfaces): Ports are used to connect routers to other devices in the network. Routers can have these types of ports:連接埠（也稱為介面）：連接埠用來將路由器連接到網路中的其他裝置。路由器可具備以下類型的連接埠：
- Management ports: Routers have a console port that can be used to attach to a terminal used for management, configuration, and control. High-end routers may also have a dedicated Ethernet port that can be used only for management. An IP address can be assigned to the Ethernet port, and the router can be accessed from a management subnet. The auxiliary (AUX) interface on a router is used for remote management of the router. Typically, a modem is connected to the AUX interface for dial-in access. From a security standpoint, enabling the option to connect remotely to a network device carries with it the responsibility of vigilant device security.管理連接埠：路由器有一個主控台連接埠，可用來連接終端機以進行管理、設定與控制。高階路由器可能還有專用的 Ethernet 連接埠，僅用於管理用途。此 Ethernet 連接埠可指派 IP 位址，並可從管理子網路存取路由器。路由器上的輔助（AUX）介面用於遠端管理路由器。通常會將數據機連接到 AUX 介面以進行撥入存取。從安全角度來看，啟用遠端連接網路裝置的選項，伴隨著必須時刻留意裝置安全性的責任。
- Network ports: The router has many network ports, including various LAN or WAN media ports, which may be copper or fiber cable. IP addresses are assigned to network ports.網路連接埠：路由器擁有許多網路連接埠，包括各種 LAN 或 WAN 傳輸媒介連接埠，可能是銅纜或光纖線材。IP 位址會指派給網路連接埠。
As an example, the following figure shows the ports on a Cisco Integrated Services Router (ISR) 4331 Router:
舉例來說，下圖顯示 Cisco 整合式服務路由器（ISR）4331 上的連接埠：
You have just finished configuring your router and saved running-config to startup-config. Which router component will store the router configuration even after the router powers down?你剛完成路由器的設定，並將 running-config 儲存到 startup-config。哪個路由器元件會在路由器關閉電源後，仍儲存路由器的設定？