IGP Routing Protocol Algorithms Metrics and Administrative Distance

IGP (Interior Gateway Protocol) is a type of routing protocol that is designed to be used within an autonomous system (AS) to distribute routing information. There are several different IGP routing protocols, including RIP, OSPF, and IS-IS.

Routing algorithms used by IGP protocols are designed to calculate the best path for traffic to take between two points on a network. These algorithms consider various factors, including the cost of each link and the bandwidth available on each link, to determine the optimal path.

Metrics are used to quantify the cost of a particular path or link. Different routing protocols use different metrics. For example, RIP uses hop count as its metric, while OSPF uses a more complex metric that takes into account the bandwidth and delay of each link.

Administrative distance is a value that is used to rate the trustworthiness of routing information received from different sources. When multiple routing protocols provide information about the same destination network, the router must determine which source of information to trust. The routing protocol with the lowest administrative distance is considered the most trustworthy and is used to route traffic to the destination network.