ospf and bgp interview questions and answers pdf

Explain BGP Local preference? Local preference is an indication to the AS about which path has a preference to exit the AS in order to reach a certain network. A path with a higher local preference is preferred more. By default value for local preference is 100 and can be changed manually. Unlike the weight attribute, which is only relevant to the local router, local preference attribute is communicated throughout a single AS for the purpose of influencing the choice of best path to exit the AS.

What is the difference between the hard reset and soft reset in BGP? In case of hard reset the local router brings down the neighborship, brings down the underlying TCP connection and all the BGP table entries learned from that neighbor are removed. #clear ip bgp * command is used for hard reset. In case of a soft reset, the router does not bring down the BGP neighborship or the underlying TCP connection. However, the local router resends outgoing Updates and reprocesses incoming Updates adjusting the BGP table based on the current configuration. #clear ip bgp * soft command is used for soft reset.

What is Recursive Lookup? The router looks up the BGP route and the next hop to reach a destination in the remote AS. Then the router looks up the route to reach the next hop. In this way router has to perform lookup twice to reach to a destination, this process is called recursive lookup.

Explain BGP Weight attribute? The weight attribute is a Cisco proprietary attribute that is used in the path selection process when there is more than one route to the same destination. A path with the Higher weight value is preferred. The default value for weight is 0. The weight attribute is local to the router and is not propagated to any BGP peers. The weight attribute is set by a router when receiving updates influencing that one router’s route for a prefix.

Explain the Border Gateway Protocol (BGP)? Border Gateway Protocol advertises, learns and chooses the best paths inside the global Internet. When two ISPs connect, they typically use BGP to exchange routing information. Enterprises also sometimes use BGP to exchange routing information with ISPs, allowing the enterprise routers to learn internet routes. when we have multiple Internet connections and we want to influence some packets to take one path and some packets to take another we use BGP.

Most Commonly Asked BGP Interview Questions

Frequently requested BGP questions, such as scenario-based BGP interview questions and BGP troubleshooting interview questions and answers, have been addressed in this blog.

Top 13 Up-to-Date BGP Interview Questions and Answers in 2022:

Border Gateway Protocol (BGP) is one of the most important topics to cover in Cisco Certified Network Professional’s core exam or BGP Interview Questions, i.e., ENCOR 350-401. In this blog, we will cover most-asked BGP interview questions and answers.

In this blog we have covered frequently asked BGP questions such as scenario based BGP interview questions and BGP troubleshooting interview questions and answers.

Assuming you have looked up BGP interview questions, you already know what BGP is. But if you don’t, let’s start right from the basics.

BGP Interview Questions and Answers for Freshers

Border Gateway Protocol (BGP) is a protocol that allows two networks to communicate with one other. BGP is a standardized outside gateway protocol that allows autonomous systems (AS) on the Internet to share routing and reachability information. A route vector protocol is what the protocol is called. The Border Gateway Protocol is engaged in fundamental routing choices and determines routing decisions depending on pathways, network regulations, or rule sets a network administrator provides.

Within an autonomous system, BGP may be utilized for routing. Interior Border Gateway Protocol, often known as Internal BGP or iBGP, is used in this application. The protocols Internet implementation, on the other hand, is known as Exterior Border Gateway Protocol, External BGP, or eBGP.

FAQ

How does BGP work with OSPF?

BGP and OSPF work together in a network to provide reachability (that is, routing) information to routers about networks outside the OSPF network. In a provider network, BGP populates the routing table, with the address of the eBGP neighbor, as the next hop for routes to exterior autonomous systems.

Why is BGP so different from OSPF?

BGP Interview Questions for Experienced
  • Differentiate between Open Shortest Path First (OSPF) and Border Gateway Protocol (BGP). …
  • Differentiate between hard reset and soft reset in the context of BGP. …
  • What do the various BGP Path Attributes mean? …
  • What do you understand about communities in the context of BGP?

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