Layer 3 (Network Layer) – Responsible for routing packets between networksIPv4 packet = IPv4 header + payload 🔹 IPv4 Header Fields Field Bits Description Version 4 IP version: 4 for IPv4 (0100), 6 for IPv6 (0110) IHL (Internet Header Length) 4 Header size in 4-byte blocks. Min: 5 (20 bytes), Max: 15 (60 bytes) DSCP…
Default Behavior of Interfaces Device Interface Default When Device is Plugged In Switch No shutdown command Goes up/up automatically Router Has shutdown command Stays admin down/down, must be enabled manually 🟡 Switch Interfaces 🔴 Router Interfaces Interface Status Commands SW1# show ip interface brief // Summary (L1/L2) – works for routers/switches SW1# show interfaces status…
Layer 3 and IP IP Broadcast Binary Conversion Binary to Decimal Decimal to Binary Number Systems Base Description Binary Base-2 → powers of 2 Decimal Base-10 → powers of 10 Hexadecimal Base-16 → powers of 16 IPv4 Address Classes Class Binary Start Range Notes A 0xxxxxxx 1–126 0.0.0.0 reserved, 127.x.x.x is loopback B 10xxxxxx 128–191…