Introduction
簡介
You have just been tasked with optimizing network efficiency within your company network. There is a suspicion that traffic from some PCs is perhaps taking a suboptimal route. The traffic appears to route through a branch office before reaching the internet, which is causing unnecessary delays and bandwidth issues. Your mission is to investigate these network paths and identify any issues.
你剛被指派負責優化公司網路的網路效率。有人懷疑部分電腦的流量可能走了不理想的路徑。流量似乎在到達網際網路之前先繞經一個分公司，造成不必要的延遲與頻寬問題。你的任務是調查這些網路路徑並找出問題所在。
With data paths, keep in mind that:
關於資料路徑，請記住以下幾點：
- Traffic might be inadvertently routed through the branch office due to misconfigurations in routing protocols or incorrect static route entries.由於路由協定設定錯誤或靜態路由項目不正確，流量可能會不慎經過分公司。
- Changes in the network topology or the integration of new devices and services could have altered optimal routing paths without corresponding updates to routing configurations.網路拓樸的變動，或新裝置與服務的整合，可能已改變了最佳路由路徑，但路由設定卻未相應更新。
- Limited visibility into all network segments might obscure the full path that packets take, complicating efforts to diagnose and correct the suboptimal routing.對所有網路區段的可見度有限，可能會掩蓋封包所走的完整路徑，使診斷與修正不理想路由的工作更加複雜。
According to the network documentation, the PC should take the optimal path to reach the internet, as shown in the figure. How can you verify this and confirm any routing issues relating to packet delivery?
根據網路文件，如圖所示，該電腦應走最佳路徑到達網際網路。你要如何驗證這一點，並確認任何與封包傳遞相關的路由問題？
Having a thorough understanding of traffic paths is crucial because it enables you to ensure optimal network performance and reliability. By investigating and interpreting how data moves through the network, you can identify and resolve bottlenecks, inefficiencies, or misconfigurations that may impact network speed, availability, and security.
深入了解流量路徑至關重要，因為這能讓你確保網路效能與可靠性維持在最佳狀態。透過調查與解讀資料在網路中如何移動，你可以找出並解決可能影響網路速度、可用性與安全性的瓶頸、低效率之處或設定錯誤。
In this course, you will:
在本課程中，你將：
- Deepen your understanding of the packet delivery process.深化你對封包傳遞流程的理解。
- Identify the key concepts such as Layer 2 and Layer 3 addressing.找出關鍵概念，例如第 2 層與第 3 層定址。
- Learn the function of default gateways.了解預設閘道的功能。
- Discover the mechanics of the Address Resolution Protocol (ARP).探索位址解析協定（ARP）的運作機制。
- Learn how to configure network devices for optimal host-to-host packet delivery.學習如何設定網路裝置，以達到最佳的主機對主機封包傳遞。
- Make informed packet forwarding decisions using routing tables and ARP information.利用路由表與 ARP 資訊做出明智的封包轉送決策。
In the figure, you can see how the Traceroute tool indicates that traffic is taking an indirect route, likely causing slow speeds and high latency. Traceroute is just one tool you will learn to use in this course that will help you interpret how packets are being forwarded in a network.
在圖中，你可以看到 Traceroute 工具顯示流量走了間接路徑，很可能造成速度緩慢與高延遲。Traceroute 只是本課程中你將學會使用的其中一項工具，可協助你解讀封包在網路中是如何被轉送的。