Routing
Routing is the process of choosing the next hop for a packet based on its destination address. It stays mostly invisible in a single small network, but once subnets, VPNs, internet gateways, and multiple sites are involved, routing rules determine the real path traffic follows.
βΆArchitecture Diagram
π StructureDashed line animations indicate the flow direction of data or requests
When there is only one subnet, packets rarely need complex decisions. But once internal networks, the public internet, remote offices, and VPN links are all attached, the network has to decide where each packet should go next. Without a rule set for that, packets either take the wrong path or get dropped altogether.
In early small networks, direct communication inside one broadcast domain was often enough. As the internet and enterprise networks expanded, operators had to stitch multiple networks together and needed a common way to decide where packets should be forwarded. Routing became one of the core capabilities of the network layer because it solved that scaling problem.
A router examines the destination IP and searches the route table for the most specific matching prefix. One private range might be sent to a branch router or a VPN gateway, while everything else follows a default route toward the internet edge. That repeated mapping of destination prefix to next hop is what turns disconnected links into a navigable network.
Routing and load balancing both send traffic onward, but they use different decision criteria. Routing chooses a path based on the destination network prefix, while a load balancer chooses which backend instance behind the same service should receive the request. Network-to-network path selection is a routing problem; service-level distribution is a load-balancing problem.
Routing fits office and data-center interconnection, internet egress paths, VPN connectivity, branch-office networking, and cloud network design. It does not solve HTTP-aware decisions or service-level backend distribution on its own. As route tables grow, keeping their priority and intent readable becomes critical for troubleshooting.