Getting selected for an interview round and not getting worried about the possible set of questions that can be asked to the candidate is impossible.
But you don’t have to worry much because we have sorted the BGP interview questions for experienced CCNA and CCNP for you.
So, if you are appearing for this interview, don’t forget to check the information given below.
Table of Contents
Here are the top 6 questions that are mostly asked in a BGP interview:
1. What is BGP?
This is probably the very first, basic, obvious, and sort of important question your interviewer can ask you. And the answer to this one is:
BGP stands for Border Gateway Protocol. The main function of BGP is the routing protocol used on the Internet.
Apart from that, BGP is also considered as a path vector protocol & its routing metric is based on paths, network-policies sets by a network administrator.
Border Gateway Protocol is also used for large networks and normally for connecting different ISPs.
2. What are BGP path selection criteria?
While we cannot tell you in which order this question can be asked, but what we can tell you is that this question is very important and you must remember the answer to this one.
Here is your answer:
- The maximum value of the local preference.
- The maximum weight value.
- The shortest path through autonomous systems.
- Prefer the local route of the router (next-hop = 0.0.0.0).
- The minimum value of MED.
- The minimum value of the origin code.
- The eBGP path is better than the iBGP path.
- Choose a path through the nearest IGP neighbor.
- Select the oldest route for the eBGP path.
- The neighbor with the lowest BGP router ID.
- Lastly, the neighbor with the smallest IP address
3. When to use BGP?
One must know the uses of something they are studying for so long, isn’t it? And that is why this question is important too. Here are the top 3 uses of BGP:
- Normally BGP is used in a large ISP environment.
- BGP can also be used to establish a connection between different autonomous systems.
- BGP is a good option in transit autonomous systems, which means that you can allow your data packets to move through from one autonomous system to another autonomous system with the help of BGP.
4. What is the loop prevention mechanism in BGP?
There are majorly two mechanisms in BGP to prevent its loops. And these methods are:
- When a router learns routes from an iBGP peer, that router does not advertise the same routes to another iBGP peer.
- While advertising to an eBGP router/peer, a BGP router adds its own A SN to the AS-PATH. If a BGP router receives an update & route advertisement lists an AS-PATH with its ASN, then the router ignores that route.
5. Explain some basic characteristics of BGP?
As you know, BGP is a path-vector protocol, and the following are the common characteristics that are associated with BGP:
- The protocol metric is called path-vector or attributes.
- Sends updates only after network changes with no periodic updates.
- Uses TCP to transfer data, this ensures reliable delivery of protocol updates (port 179).
- Periodically sends keepalive messages to verify TCP connections.
6. Name some famous BGP metric attributes?
When you are sitting in a room where the interview is about your BGP knowledge, you must expect all questions related to BGP and be prepared to explain them all properly.
Here are the attributes on which the BGP path selection depends:
- Router ID
- Local Preference
- Shortest IGP path to BGP next-hop
- Oldest path
- Neighbor IP address
- Origin code
- AS path length
- eBGP path over iBGP path
Now that you know most of the potential questions that can be asked in your BGP interview, don’t waste your time in preparing them.
To Sum Up:
Every interviewee is always worried about what questions they will have to answer in an interview that is too important for them.
And same goes for our BGP expert friends, but now anymore as the questions and answers are given above for BGP interview questions for experienced CCNA and CCNP candidates will help them ace their interview.