Port 179
Border Gateway Protocol
BGP (Border Gateway Protocol) is a standardized exterior gateway protocol designed to exchange routing information between autonomous systems (ASes) on the Internet. It forms the backbone of routing decisions across the global Internet, helping network operators determine the most efficient paths for data. Due to its importance, BGP plays a crucial role in maintaining overall Internet connectivity and stability..
Technical Details
Overview
Border Gateway Protocol (BGP) is the protocol used to exchange routing information between different autonomous systems (ASes) on the Internet. It is classified as a path vector protocol and is defined in various RFCs, notably RFC 4271. BGP makes routing decisions based on network policies, path attributes, and rule sets.
Functionality
BGP facilitates inter-domain routing by enabling routers in different administrative domains to advertise, learn, and select the best routes to destination networks. It distinguishes itself from Interior Gateway Protocols (IGPs) like OSPF or EIGRP by scale and policy control rather than convergence speed. BGP operates over TCP, typically on port 179, providing reliable transit for routing updates.
Types and Features
There are two primary forms of BGP: external BGP (eBGP), used between different ASes, and internal BGP (iBGP), used within the same AS. BGP uses path attributes such as AS_PATH, NEXT_HOP, and LOCAL_PREF to determine route selection. It supports advanced features like route reflectors, confederations, multipath, and route-maps for granular control over routing behavior.