Routing Showdown: Which Protocol Reigns Supreme – EGP or IGP?
Routing protocols are essential for effective communication in computer networks. They determine the path that data takes from one network to another, making it possible for devices to communicate with each other. Within routing protocols, two protocols stand out for their importance – Exterior Gateway Protocol (EGP) and Interior Gateway Protocol (IGP). Both protocols play a crucial role in the overall operation and performance of a network.
EGP
Exterior Gateway Protocol (EGP) is a communication protocol that was used in the early stages of the internet’s development. It belongs to the class of routing protocols that communicate between networks. Therefore, it is also known as an inter-domain routing protocol or an exterior routing protocol. EGP is designed to operate between autonomous systems (AS) connected to the internet. An autonomous system is an interconnected group of networks that are administered by a single organization, under a single administrative domain.
EGP works by sharing information about the available routes between autonomous systems (AS), enabling the best path to be chosen for a given set of data. EGP communicates only the reachability of a destination between Autonomous Systems (AS). The protocol is not sophisticated enough to choose the shortest or fastest path between two points; it is up to the receiving AS to decide which available route it prefers.
IGP
Interior Gateway Protocol (IGP) is a routing protocol that is used within a single autonomous system. It is also known as an intradomain routing protocol. IGP’s primary function is to determine the best path between devices within a network. Unlike EGP, IGP aims to calculate the shortest path between two points within an autonomous system. This makes it ideal for intranet communication where the network is confined within the walls of a single organization.
IGP protocols include Open Shortest Path First (OSPF), Routing Information Protocol (RIP), and Intermediate System to Intermediate System (IS-IS), amongst others. Each protocol sets different parameters for determining the shortest path between two points within a network. For instance, OSPF uses a link-state algorithm, while RIP uses only hop count.
EGP vs. IGP
The fundamental difference between IGP and EGP protocols lies in their scope. As we have seen, IGP is concerned with communication within a single autonomous system. On the other hand, EGP concentrates on communication between autonomous systems. In terms of decision-making, IGP routes packets based on network topology, whereas EGP routes are determined by policies set by the AS.
One of the benefits of EGP is that it allows autonomous systems to exchange routing information even if they use different IGP protocols within their network. EGP allows for intercommunication and the sharing of traffic between autonomous systems, regardless of their internal network setup. EGP also allows administrators to assign different costs to their routes, providing the ability to balance traffic between ASs.
In contrast, IGP is ideal for situations where a network needs to exchange information within its internal network. IGP algorithms aim to find the shortest path between endpoints of a network, ensuring that data is transmitted effectively over network links.
Final Thoughts
Both IGP and EGP are critical components of routing protocols, and they play different roles in network communication. EGP protocols facilitate communication between autonomous systems, while IGP routes packets within a single autonomous system. Both protocols are necessary for the overall operation of a network, and each has its advantages and limitations. Therefore, deciding which protocol reigns supreme is dependent on the network’s requirements and use case.