BGP interview questions

 BGP protocol interview questions

Q. What is a Local Preference?

Q. What is the difference between EBGP and IBGP neighborship ?
Q. What transport protocol does BGP use?
Q. What is an AS_PATH and what is it used for?

Q. How can you use BGP for load balancing traffic outbound?

Q. How can you use BGP for load balancing traffic inbound? 
Q What is the final tiebreaker in BGP path selection criteria?
Q What are the three well known mandatory attributes? What does a well known mandatory attribute imply?
Q What is BGP conditional-routing ?? 
Q Explain the BGP route selection process?
Q. How BGP multipath works?
Q. Why IBGP full mesh required ? 
Q. BGP is link state or distance vector protocol or path vector protocol ? Explain why ?
Q. When do we use BGP in network ?
Q. When we can  use BGP instead of any IGP ? Is it option ?
Q. Types of BGP routing table?
Q. Define various BGP path attributes and different types.
Q. Why weight is different path attributes ?
Q. What is confederation?
Q. What is route reflector and why it is required?

Q. What address can be used for the BGP neiborship ? Interface or Loopback ?

Q. What is Hierarchical FIB - BGP-PIC?

Q. BGP Graceful Restart, NSR and NSF ?
Q. BGP Redistribution Vs MPLS, which one you will select? 
Q. How to trigger black hole remotely ? 
Q. What is the difference/similarities between Route reflector and Route server ?
Q. When does BGP use 0.0.0.0 router id?
Q. Does route reflector come in actual path during traffic forwarding?
Q. What is Site of origin  SOO?
Q. What is the cost of external and internal BGP routes ?
Q. Can we use local preference outside the autonomous system?
Q. Does it require that BGP router-id should reachable in cloud?
Q. What is recursive lookup in BGP and how it works?
Q. If a static route is advertised in BGP without using update source what will be the next hop address in update?
Q. Define various types of communities and why they are used?
Q. Troubleshoot idle state in BGP ?
Q. How many links can be assigned for load balancing or sharing?
Q. In eBGP I am establishing my neighborship with loopback address but it’s not coming up. Please specify different reasons.
Q. Can we redistribute BGP in IGP? Please explain your answers.
Q. What is cluster id?
Q. Receiving updates from eBGP peer, will the next hop change or not?
Q. Receiving updates from iBGP peer, will the next hop change or not?
Q. How loop prevention mechanism works in BGP.
Q. What will happen if route reflector is not getting proper updates?
Q. What will happen if route reflectors does not synchronize?
Q. What is the advantage of using BGP AS Prepend?
Q. What is BGP PIC?
Q. Use BGP as Link Protection in case of Dual PoP?
Q. How to achieve Inter-AS Communication MP-eBGP?
Q. What can happen if Route Reflector(RR) is not getting proper route updates?
Q. What is route reflector synchronization?
Q. What are the common best practices to connect with ISP through BGP ?
Q. What are the latest trends for the load balancing mechanism with ISP ?
Q What are the best practices to configure BGP ?
Q. How to use BGP as PE-CE backdoor link?