Routing protocols are the way networks communicate with each other and share information on the internet. There are two types of routing protocols, interior gateway protocols (IGP) and border gateway protocols (BGP). Understanding the differences between these protocols is essential for network administrators to ensure a stable and reliable network infrastructure.
Interior Gateway Protocols (IGP)
Interior Gateway Protocols (IGP) are used within autonomous systems (AS) to communicate between routers. An AS is a network that is under a single administration and is usually confined to a particular geographical location. IGPs are designed for this specific use case and are used to route packets between internal networks within an AS.
Popular examples of IGPs include Open Shortest Path First (OSPF), Routing Information Protocol (RIP), and Intermediate System to Intermediate System (IS-IS).
IGPs use metrics to determine the best path for packets to take. Metrics can include the number of hops, link bandwidth, delay, and reliability. Metrics are useful for finding the most efficient path for packets within a particular AS.
Border Gateway Protocols (BGP)
Border Gateway Protocols (BGP) are used to exchange routing information between different autonomous systems. BGP is used when an AS is connected to other ASes through multiple gateways, and a routing decision cannot be easily made within the AS.
BGP uses policies to decide which paths to choose for packets. Policies can include filtering, route preference, and cost. This gives network administrators greater control over how traffic is routed outside of their AS.
BGP is a highly scalable protocol designed to handle the complexity of a global network. It can be used to route traffic across multiple ASes efficiently.
Key Differences between IGP and BGP
The primary difference between IGP and BGP is the scope of the network. IGPs are used for routing packets within an AS, while BGP is used for routing packets between different ASes.
IGPs use metrics to determine the best path for a packet within an AS, while BGP uses policies to choose the best path between ASes.
IGPs are designed for use in small to medium-sized networks, while BGP is designed for large-scale networks.
Conclusion
In conclusion, understanding the differences between IGP and BGP is critical for maintaining a reliable network infrastructure. IGPs are used within autonomous systems to route packets between internal networks, while BGP is used to route packets between different autonomous systems. IGPs use metrics to determine the best path for packets, while BGP uses policies. By implementing the right routing protocol for your network, you can ensure a stable and efficient network infrastructure.