Reititystaulusta

Reititystaulusta, often translated as routing table, is a data table stored in a router or host that keeps track of the paths that data packets can take to reach different network destinations. It is a fundamental component of network routing, enabling devices to determine the best outgoing interface or next hop for a packet based on its destination IP address. Each entry in a routing table typically includes the destination network address, the subnet mask, the gateway or next hop IP address, and the metric associated with that route. The metric represents the cost or preference of a particular route, with lower values generally indicating a more desirable path.

When a router receives a packet, it examines the destination IP address and compares it with the entries in its routing table. The router performs a longest prefix match to find the most specific route that matches the destination address. If a match is found, the router forwards the packet to the specified next hop or outgoing interface. If no specific route is found, the packet may be sent to a default gateway, which is a preconfigured route that handles traffic destined for networks not explicitly listed in the table. Routing tables are dynamically updated through routing protocols such as RIP, OSPF, and BGP, which exchange routing information between routers to adapt to network changes and maintain optimal path selection.