OSPF would require intensive use of memory as well as CPU resources. With BGP on the other hand, the size of the routing table is going to be dictated the required device resources. BGP is considered to be more flexible as well as scalable than OSPF and it would be also used on a larger network.Accordingly, why is BGP so different from OSPF?
The OSPF follows a hierarchical structure whereas BGP usually adopts mesh structure. OSPF requires intensive use of memory and CPU resources. As against, in BGP the need of device resources relies on the size of the routing table. BGP is more flexible and scalable than OSPF and used on a larger network, unlike OSPF.
Additionally, why do we need BGP? The main advantage of BGP is that it gives you much more control over what routes you advertise and what advertisements you accept from your neighbors. BGP gives you more control over route selection and your neighbor's route selection. That's one of the major reasons BGP is The Routing Protocol for the Internet.
Secondly, why OSPF is preferred over BGP?
OSPF prefers fastest path rather than shortest path. In Open Shortest Path First, internet protocol is used. Border Gateway Protocol (BGP): Border gateway protocol prefers best path.
How does BGP work with OSPF?
OSPF is an IGP (internal gateway protocol), while BGP is the only real EGP (exterior gateway protocol) currently. If you are doing internal routing, i.e. routing within a site, company, or campus, you will want to use OSPF. Typically BGP is needed at a site edge, where you route out to the public internet.
Is BGP classless?
RIP-1 and IGRP are grouped under classful protocols, whereas the more recently developed RIP-2, EIGRP, OSPF, IS-IS, and BGP fall in the classless category. The Exterior Gateway Protocol (EGP), the predecessor of the Border Gateway Protocol (BGP), which currently is considered obsolete, is also a classful protocol.Why BGP is used in MPLS?
In a MPLS network that is used to provide internet services and L3 VPN services BGP is typically carrying the internet routing table, customers' IPv4/IPv6 routing information and VPNv4 routing information with VPN labels. To summarize; BGP is used to carry the following information: Internet routing information.Why BGP convergence is slow?
Failure detection and propagation by means of BGP mechanics is slow, and depends on the number of affected prefixes. Therefore, the more severe is the damage, the slower it is propagated in the BGP. Some other, non-BGP mechanism needs to be used to report network failures and trigger BGP re-convergence.Does BGP need IGP?
But BGP only handles the exterior side of routing—there's also interior routing. And there's a lot more choice in Interior Gateway Protocols (IGPs). An old favorite is RIP, the Routing Information Protocol. Networks that run both IP versions and use OSPF as their IGP thus need to run both OSPFv2 and OSPFv3.Why BGP is called path vector protocol?
Border Gateway Protocol (BGP) is an example of a path vector protocol. In BGP, the autonomous system boundary routers (ASBR) send path-vector messages to advertise the reachability of networks. It modifies the routing table to maintain the autonomous systems that are traversed in order to reach the destination system.Is BGP a dynamic routing protocol?
The dynamic routing protocol that is the most different from all the others is the Border Gateway Protocol (BGP). RIP, EIGRP and OSPF are all interior gateway protocols (IGP) while BGP is an exterior gateway protocol (EGP).Why we use OSPF?
The idea behind the OSPF areas is to lower the amount of routing traffic and lower the processing of your core routers. Different areas are connected with each other through Area Border Router (ABR). OSPF is link state routing protocol and you can tune a link state routing protocol to converge fast.Does OSPF uses TCP or UDP?
Open Shortest Path First (OSPF) is a link-state routing protocol. OSPF does not use a TCP/IP transport protocol (UDP, TCP), but is encapsulated directly in IP datagrams with protocol number 89. BGP uses the Transmission Control Protocol (TCP) as its transport protocol, and is assigned the reserved port 179.Is BGP a layer 3 protocol?
For the most part, routing is a layer-3 function, but, as you pointed out, BGP uses a layer-4 protocol to communicate with other BGP speakers in order to do what is normally considered a layer-3 function. Many network protocols fall into a gray area, or are considered in one layer while using another layer.Why Eigrp is better than OSPF?
EIGRP is also less confusing than OSPF because it does not have different network types and EIGRP is easier to deploy in hub and spoke scenarios. OSPF can only summarize between areas. OSPF is link state so it has a better view of the entire network than EIGRP before it runs the SPF algorithm.What is Area 0 called in OSPF?
OSPF Areas. OSPF operates within a single autonomous system (AS). The backbone area (Area 0) is the core of an OSPF network. All other areas are connected to it and all traffic between areas must traverse it. All routing between areas is distributed through the backbone area.Why OSPF is better than Rip?
In terms of number of packets lost, OSPF is better compared to RIP in small networks but RIP is better in large networks. OSPF is better than RIP for many reasons: OSPF uses either bandwidth or delay as metric for shortest path and it does not use the number of hops as in RIP.Why is IGP used in BGP?
To solve this, IGP is used in the ISP network to exchange specific topology information for reaching the next-hops within the ISP core. BGP advertises the external prefix with next-hop and IGP advertises the route to reach the next-hop. IGP handles all internal routes and BGP handles all global internet routes.Why do we need AREA 0 in OSPF?
Because other areas don't have full information about each other all inter area traffic must pass through area 0. Otherwise there could be routing loops because not having the full topology. Due to this design OSPF does not have to run full SPF when links go up/down in other areas.What is BGP advertisement?
BGP is a PATH VECTOR protocol, which means that it does not keep track of internal routing within the AS, but rather keeps track of paths through other autonomous systems to reach destination networks. Any network that is not being advertised, cannot be reached. BGP uses the UPDATE message to advertise routes.Why do we use routing?
The main purpose of a router is to connect multiple networks and forward packets destined either for its own networks or other networks. A router is considered a layer-3 device because its primary forwarding decision is based on the information in the layer-3 IP packet, specifically the destination IP address.What is synchronization rule in BGP?
The BGP synchronization rule states that if an AS provides transit service to another AS, BGP should not advertise a route until all of the routers within the AS have learned about the route via an IGP. 
