What does BGP stand for?
BGP stands for Border Gateway Protocol. The path-vector routing protocol that connects autonomous systems and carries the internet's routing between ISPs. It runs over TCP port 179 and chooses routes by policy and AS path rather than simple metrics; inside one organization, OSPF or EIGRP is the usual choice.
BGP is the routing protocol that connects the networks of the internet to each other. Each large network, called an autonomous system, uses BGP to tell its neighbours which address ranges can be reached through it. Routers choose among paths by policy and by the list of autonomous systems a route passes through, not by link speed. BGP sessions run over TCP port 179. The protocol was built on trust between operators, so a wrong announcement, by mistake or on purpose, can pull traffic to the wrong place.
BGP in practice: an example
A company has two internet providers. Its edge routers run BGP with both and announce the company's address range through each. When one provider's link fails, the announcement through that provider disappears and the rest of the internet reaches the company through the other, without anyone changing a setting.
What BGP is confused with
BGP vs OSPF: what is the difference?
OSPF is an interior protocol: it finds the fastest path inside one organization's network. BGP is an exterior protocol: it exchanges reachability between separate organizations according to policy. What OSPF stands for
Which exams cover BGP?
BGP is on the official CompTIA acronym list for one of the four exams covered here.
- Network+ N10-009: 2.0 (Network Implementation).
Each number is a CompTIA exam objective and the name in brackets is its domain. The exam puts the term in a scenario; it does not ask you to recite the expansion.
Check yourself: two practice questions
Written by CertSprint for this page. They are not taken from any exam.
1. Which routing protocol do internet providers use to exchange routes with each other?
- RIP
- OSPF
- BGP
- STP
Show the answer
C. BGP. BGP is the exterior gateway protocol of the internet. RIP and OSPF work inside one organization, and STP is not a routing protocol.
2. A network announces address ranges that belong to another organization, and traffic for that organization is misdirected. What is this called?
- BGP hijacking
- VLAN hopping
- DNS poisoning
- MAC flooding
Show the answer
A. BGP hijacking. Because BGP accepts announcements on trust, a false origin can attract traffic meant for the real owner. Filtering and route origin validation reduce the risk.
Sources: RFC 4271: A Border Gateway Protocol 4 (BGP-4); NIST SP 800-189, Resilient Interdomain Traffic Exchange: BGP Security and DDoS Mitigation; NIST glossary: Border Gateway Protocol. The acronym and its expansion come from CompTIA's official acronym lists, linked from each exam glossary above. The explanation, example and questions are CertSprint's own, checked against these sources on 11 November 2026.