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OSPF vs BGP: Which Routing Protocol to Use?

Posted on By FS.COM

Routing protocols represent a set of rules or algorithms that instruct routers on how to communicate with each other, so they can redirect traffic to the best path. There are several routing protocols, and the type of routing protocol chosen is essential for every network administrator. We will now provide a better explanation on how to use the OSPF and BGP routing protocols and how to choose between OSPF vs BGP according to your needs.

routing protocol

OSPF vs BGP: OSPF Is an Interior Routing Protocol (IGP)

OSPF (Open Shortest Path First) is the most commonly used Interior Gateway Protocol (IGP) in large enterprise networks. OSPF works by calculating the fastest path between the source and destination and then sending data packets on a route that has the least amount of traffic. So the shortest here means the time it takes for data packets to travel from point A to point B. As a link state routing protocol, OSPF works for intra-domain routing that operates within a single autonomous system (AS). Link state represents the basic information of a router and its immediate connections and then the OSPF protocol puts together the information and calculates the shortest path between any two points. Some of the most important reasons for implementing OSPF protocol are:

 Reducing routing overheads for companies
 Achieving network redundancy
 Optimizing performance of local area networks (LAN)

OSPF vs BGP: BGP the Only Available Exterior Routing Protocol (ERP)

BGP (Border Gateway Protocol) is a routing protocol that makes routing decisions across the Internet - usually externally rather than internally. BGP works towards changing routing information between gateway hosts in a network of autonomous systems – it establishes routing between users and allows for peering and carrier networks to connect. Unlike the OSPF used in a large enterprise network, BGP is usually applied between Internet service providers. It includes cost metrics for each path so that packets take the most efficient route. The benefits of BGP routing include:

 Achieving redundancy
 Preventing traffic from being sent across an expensive and low capacity link
what is ospf vs bgp

OSPF vs BGP: What Is the Difference?

The main difference between OSPF vs BGP is that the OSPF is an intra-domain routing protocol using link state routing, and the routing operation is performed inside an autonomous system while BGP is the inter-domain routing protocol that uses path vector routing, with the routing operations performed between two autonomous systems. Some other distinctions between OSPF vs BGP include:

 OSPF is easily-configured while BGP configuration is a lot more complex.
 OSPF can achieve convergence (the time a router takes to share and update the latest routing information) faster. In contrast, the BGP has a slow convergence rate.
 The OSPF follows a hierarchical structure whereas BGP usually adopts mesh structure.
 OSPF requires intensive use of memory and CPU resources. With BGP on the other hand, the size of the routing table dictates the required device resources.
 BGP is more flexible and scalable than OSPF and it is also used on a larger network.
 OSPF is used to determine the fastest route while BGP puts emphasis on determining the best path.

Here we use a chart to summarize OSPF vs BGP differences:

Gateway Protocol Internal gateway protocol External gateway protocol
Implementation Easy Complex
Convergence Fast Slow
Design Hierarchical network possible Meshed
Need for device resources Memory and CPU Intensive Scaling is better in BGP although it relies on the size of the routing table
Size of the networks Used on primarily smaller scale network which could be administered centrally Mostly used on large scale networks such as the internet
Function The fastest route is preferred over shortest Best path is determined for the datagram
Algorithm Used Dijkstra algorithm Best path algorithm
Protocol IP TCP

OSPF vs BGP: How to Choose?

If you are conducting internal routing, such as routing within a site, company, or campus, you will want to use OSPF. BGP is typically needed at a site edge, where you route out to the public internet. If you are looking at building in-site with multiple homes, you might want to consider BGP. Moreover, for enterprise network, pick OSPF as your routing protocol. As a developed and mature protocol, OSPF is supported by the vast majority of network vendors. As a service provider, adopt the BGP to carry your customers' routes. Generally, most of the service providers would use IGP to carry Infrastructure IPs and BGP to carry customer routes.

ospf vs bgp difference

Although BGP is used between multiple autonomous systems as an external routing protocol, many network giants like Microsoft and Facebook would use it internally – in this case, BGP is typically fit for very large networks which OSPF fails to handle. One of the many reasons that BGP does not function well as an internal gateway protocol is that it is very slow to converge.


It is the routing protocol that literally makes the internet work. We’ve explained the basics of OSPF and BGP, and provided some insights on OSPF vs BGP differences and which one to select. Hope this would help to clear the confusion regarding OSPF vs BGP. FS.COM also offers professional solution in relation to network devices, including Ethernet routers, servers, data switch (e.g. 10GB Ethernet switch and etc) and PoE network switch. For more details, feel free to contact us at sales@fs.com.

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