The data link layer builds a frame around the network layer data so the necessary checks and controls can be applied. 資料鏈結層在網路層資料之外建立一個訊框，如此一來必要的檢查和控制才能被套用。
WAN standards typically describe both physical layer delivery methods and data link layer requirements, including physical addressing, flow control, and encapsulation. 廣域網路標準典型地描述實體層的傳送方法和資料鏈結層的需求，包括實體層定址，流量控制和封裝。
Hubs and switches operate at the Data Link Layer. 開關運轉樞紐和數據鏈路層。
To alleviate this, bridging was created to communicate at the data link layer while isolating the physical layer. 為了減輕這個問題，橋接方法被採用，在工工作在物理層的中繼器之基礎上，橋接工作在數據鏈路層。
