Layer 2 - Data Link

Layer 2 is responsible of sending packets over the network.

When a smartphone connects to a network, uses a Point to Point Layer 2 connection using LTE/4G/5G, and it's connected to Local Network Area (LAN) using WiFi. Layer 2 supports protocols HDLC, PPP(Point to Point Protocol) in Point to Point connections and Ethernet(IEEE 802.3 802.11) in LAN (Local Area Networks). Hence Internet Packet passes only through two types of networks: Point to Point link or Local Area Networks.