Supernetting and routing

Summarise routes and understand gateways.

📖 Key ideas

Default gateway: router address hosts use to reach other networks.
Hosts on the same subnet talk directly; others go via the gateway.
Route summarisation combines networks: 192.168.0.0/24 + 192.168.1.0/24 → 192.168.0.0/23.
Routing tables choose the longest prefix match.
Default route 0.0.0.0/0 matches everything.

💡 Real-life example: The default gateway is the colony gate: to visit another colony, you must go through it.

Default gatewayRouter for off-subnet traffic

SupernetSummarised larger network

Longest prefix matchMost specific route wins

0.0.0.0/0Default route