A link-state routing protocol builds a connectivity map of the network, then uses that map to calculate routes to destination networks. This differs from distance-vector routing, where a router learns only a destination, metric, and next-hop router from neighbors. section 17.2.1 section 17.5
Key characteristics include:
- Operates as an interior gateway protocol within a single autonomous system. section 17.5
- Uses network-wide connectivity information rather than relying only on neighbor reports. section 17.2.1 section 17.5
- Includes OSPF and IS-IS among the link-state IGPs. section 17.5
- Supports route calculation before routes are considered for routing-table installation. section 17.5
Figure 17.9 R1 builds a connectivity map of the network and uses it to calculate a route to LAN A.
The network diagram shows a router building a connectivity map and using it to calculate a route to LAN A. section 17.2.1
