I am interviewing some Sr. Network engineers for the next 2 weeks. I've composed a list of questions and am posting them here for feedback purposes. Let me know what you think.

Questions to determine level of network/Internet experience and knowledge.

1. Describe some network projects you have done. What did you do? Why? How?
2. From a high level view explain how the Internet works. (should explain transit providers, peering (public and private), tier1, tier2, root routers, DNS and root DNS servers)
3. What is the purpose of an Internet Routing Registry? Is it important? Name some of the top Internet Routing Registries.
4. Are you familiar with ARIN, RIPE, APNIC, LACNIC and AfriNIC? What role do they play in networks?
5. Where do you usually go to find AS, peering and IP info for particular networks?
6. Do you use looking glasses? Which ones?
7. How does a router work? How does a switch work? Can some switches be routers too?
8. What troubleshooting steps and procedures do you typically take when trying to isolate network issues? Give some examples.
9. What information resources do you use when designing networks? When managing networks? When troubleshooting problems?
10. How do you obtain your own IP space from ARIN? Is this important? Explain your answer.
11. What is the purpose of dynamic routing protocols? If dynamic routing protocols exist are static routes required? Explain your answer.
12. Explain design process from high level. (i.e. what is involved in designing a network?)
13. Are you familiar with Change Management. When do you use it?
14. How do you like to securely remote into network devices?
15. Explain how MPLS works from high level view. Advantages, limitations.
16. Where would you go to find official Internet Protocol standards? Why is this important?
17. What dynamic routing protocols are best suited for large diameter networks? Which ones have you worked with? What did you do? (should be BGP, OSPF, IS-IS)
18. What dynamic routing protocols are best suited for small diameter networks? Which ones have you worked with? What did you do? (should be E/IGRP, RIP)
19. Why was the OSI model developed? Is it useful? Where did it originate from?
20. Why would you upgrade the operating system of a network device? How would you execute the upgrade?
21. How do you keep up to date on trends and technologies?
22. Explain differences between IPv4 and IPv6. Explain structure of each and significance of structure. Why important? Advantages and disadvantages.
23. Explain BGP from a high level view. (should mention eBGP, iBGP, AS’s, peers, maybe even filters)
24. Explain different OSPF area types and how they function in relationship to each other. (i.e. how are routes advertised and route tables populated). Why would this be important in a network design?
25. What type of circuits have you worked with? (answer should be Point-to-point and point-to-multi-point ATM, serial, frame-relay, Ethernet, wireless)
26. Explain the role of DNS servers, syslog servers, TFTP servers, terminal servers, monitoring servers in the network. Why are they important?
27. How do different VLAN’s on a layer 2 switch communicate with each other? Is there a method that can be used if no router exists?
28. In your opinion what does network security involve? (should mention physical access, procedures, filters, monitoring, etc..)
29. Explain the differences between Layer2, 3 and 4 capable devices.
30. In your opinion, how important are network protocol timers and metrics? Explain
31. What are some typical procedures you follow prior to working on production network equipment? (backup configs and constant pings should be among top 5.)
32. What is a broadcast storm? An ARP storm?
33. How does a workstation or server connect to the network? What procedures does it go through?


Trivial technical questions: (not too important and ability to answer them will not impact my decision)

34. Explain differences between Native and Hybrid mode on Cisco 6500’s. What are advantages, disadvantages of each? http://www.cisco.com/en/US/products/hw/switches/ps708/products_white_paper09186a00800c8441.shtml
35. Does a Cisco 6500 Sup1a support SFM or SFM2 modules? What do SFM modules do?
36. You are running BGP on a Cisco 6500 Sup1a-MSFC. What does Cisco recommend with this config?
37. What does the BGP Scanner process do in Cisco IOS? How often does it run?
38. How many flash systems does a Foundry FastIron switch have?
39. What is the maximum combined throughput of a 10Mbps full duplex line?
40. How many metrics/attributes does BGP support?
41. What is the RFC number for HSRP?
42. Name the 7 steps OSPF goes through to become fully adjacent to a neighbor.
43. How does traceroute work?
44. Is Ping unicast, multicast or broadcast?
45. What is CAIDA? Is it useful?
46. Name 5 of the top 10 providers according to number of peering sessions.
47. What network equipment vendors support STP?
48. You have 5 carriers connecting to a single edge router and receiving the full BGP table from each. Is this scenario possible? Would you run into any problems? What is recommended best practice?
49. Name a protocol(s) used for failover that support virtual router interfaces.
50. What is the size of the current Internet routing table?
51. Explain how a single server with two NIC’s can connect to two separate upstream switches so that in the event one upstream switch fails then the server will not go down.
52.

Wow! Can't wait to see the answers. I can only answer 1 or 2 of these questions. Can't wait to see the answers :)

Originally posted by ichris
Wow! Can't wait to see the answers. I can only answer 1 or 2 of these questions. Can't wait to see the answers :)

Although I know the answers, answers will not be posted my friend. Sorry, but that would be silly.

Don't take this the wrong way, but an interview isn't a test.

A lot of those questions will make any network engineer think you are mocking them.

It sounds like you want them to sit down and take an exam, not discuss the finer points of network engineering.

Honestly, I know, personally, 6 network engineers and sys admin's that would walk out of your interview after you had started question 2.

Conducting an interview is a two-way thing. If you make your interviewee's feel like they are back in primary school, they will never work for you.

How about asking them proper interview questions, make them feel comfortable - just generally chat. Chatting generally with a person (mainly completely off-topic) will let you know more about the prospective employee, than a bunch of text book, robotic questions.

Surely you have some sort of 'requirements' that they need to have, to even get an interview to begin with? if not, I suggest you get some drawn up. You're going to waste your time, and the time of numerous people otherwise.


Simon

Originally posted by IHSL
Don't take this the wrong way, but an interview isn't a test.

A lot of those questions will make any network engineer think you are mocking them.

It sounds like you want them to sit down and take an exam, not discuss the finer points of network engineering.

Honestly, I know, personally, 6 network engineers and sys admin's that would walk out of your interview after you had started question 2.

Conducting an interview is a two-way thing. If you make your interviewee's feel like they are back in primary school, they will never work for you.

How about asking them proper interview questions, make them feel comfortable - just generally chat. Chatting generally with a person (mainly completely off-topic) will let you know more about the prospective employee, than a bunch of text book, robotic questions.

Surely you have some sort of 'requirements' that they need to have, to even get an interview to begin with? if not, I suggest you get some drawn up. You're going to waste your time, and the time of numerous people otherwise.

Simon


Well, if you are saying that I should not ask fundamental networking questions then what do you suggest I do to measure someone's ability? Do you think question #1 is enough to open the door to some chit-chat that will help give me an idea of their knowledge and experience?

Originally posted by appolo
Well, if you are saying that I should not ask fundamental networking questions then what do you suggest I do to measure someone's ability? Do you think question #1 is enough to open the door to some chit-chat that will help give me an idea of their knowledge and experience?
If you went for a job at a grocery store, and the store manager gave you a grocery bag, and asked you what it did, would you laugh, and think you were being made fun of?


My point is, the questions you are asking need not be asked if you are properly pre-qualifying your applicants. An interview is meant to be a platform from which you build upon what the qualifications and past experience already bring to the table.



Simon

I'm no network engineer as such but I have to agree with Simon, I think an interview is more like a 'getting to know' session than a 'how smart you are' session.

So maybe ask Q #1 then move on to a more casual 'chat'

Strange double post. (where did that 90 second rule go to?)

Originally posted by IHSL
If you went for a job at a grocery store, and the store manager gave you a grocery bag, and asked you what it did, would you laugh, and think you were being made fun of?


My point is, the questions you are asking need not be asked if you are properly pre-qualifying your applicants. An interview is meant to be a platform from which you build upon what the qualifications and past experience already bring to the table.



Simon


Interviews are indeed 'get to know' sessions.
They are also pre-qualify sessions.
No hard feelings but your illustration was pretty bad. Try an illustration that is a little closer so the two can be compared.
For example, interviewing a architect to help design and build a project. So what would you ask the architect?

Anyone else have anything to add to this?

If not then someone please close this thread.

Originally posted by appolo
Interviews are indeed 'get to know' sessions.
They are also pre-qualify sessions.
No hard feelings but your illustration was pretty bad. Try an illustration that is a little closer so the two can be compared.
For example, interviewing a architect to help design and build a project. So what would you ask the architect?
Why is my illustration bad?


You asked for suggestions, then shot mine down.


My guess is you've never conducted an interview before, hence the greenness of your approach, and your swiftness to reject any input on a question you posted in an open forum.


Good luck filling the position.

Simon

Originally posted by IHSL
Why is my illustration bad?


You asked for suggestions, then shot mine down.


My guess is you've never conducted an interview before, hence the greenness of your approach, and your swiftness to reject any input on a question you posted in an open forum.


Good luck filling the position.

Simon

Don't take it the wrong way. I was not trying to shoot you down.
I actually thought your feedback was very sound and agreed with it. It's just that I thought your illustration was bad.

In your interview, instead of a 50 question "exam", try giving the inerviewee 2 or 3 scenarios and ask what they would do to either fix it, build it, or improve it, as appropriate. These scenarios can be situations that would be commonly encountered in the job you are looking to fill.

This way you can interact more, discuss the ideas, and gauge how well your network engineer thinks on their feet.

HTH

- John C.

I've had the opportunity to participate in a few interviews and my take would be the 1st session is usually a get to know session as stated earlier, and then after you gage the person's personality then you schedule/conduct your technical interviews. I wouldn't walk out if those questions were posed to me on the first call.

my 2 cents

Originally posted by JohnCrowley
In your interview, instead of a 50 question "exam", try giving the inerviewee 2 or 3 scenarios and ask what they would do to either fix it, build it, or improve it, as appropriate. These scenarios can be situations that would be commonly encountered in the job you are looking to fill.

This way you can interact more, discuss the ideas, and gauge how well your network engineer thinks on their feet.



John gives a good suggestion. The real work scenarios differ a lot from the theoretical answers. Someone who solves the issue and someone who explains how the underlying theory works differ. It would be better if you get one with both the qualities.

Then getting a relatively less experienced person is easier when you give a test. But experienced people prefer not to go through the tests since there are opportunities for them even without this much difficulty. :)


--
psk

im asuming these are prolly local positions, to me some of the questions seemed like you could generate a good multiple choice pre screening by having them use a select 10 of them at random

for me at least it seems to me that i have the skills in a day to at leat get you all the answeres to most of your questions but they would be great to scare off the get rich quick people on WHT (no offense hopefully taken to any of you)

just a good way to get serious on the job

Originally posted by gilbert
im asuming these are prolly local positions, to me some of the questions seemed like you could generate a good multiple choice pre screening by having them use a select 10 of them at random

for me at least it seems to me that i have the skills in a day to at leat get you all the answeres to most of your questions but they would be great to scare off the get rich quick people on WHT (no offense hopefully taken to any of you)

just a good way to get serious on the job

You raise a very good point which is why I thought of the questions in the first place. I actually AM hoping to scare away the "get rich quick" people. The pompus arrogant techies who think they know stuff but actually don't. If you are a architect, a rocket scientist or a electrical engineer you better believe you are going to be tested if applying to Boeing or NASA. I figured that mature candedites would rise above the questions and not take too much offense understanding that it was a necessary evil.

The bottom line is that if you are truly a professional you will not take offense and easily be able to handle my questions right off the cuff. Many of my questions do not have specific right or wrong answers so how the candedite answers will give insight into their experience and understanding.

it was a necessary evil.............:cartman:

Originally posted by rois
I'm no network engineer as such but I have to agree with Simon, I think an interview is more like a 'getting to know' session than a 'how smart you are' session.

So maybe ask Q #1 then move on to a more casual 'chat'

Couldn't agree more. But keep in mind that "smart" people are often not the ones who build Space Shuttles and Power Plants. People who are focused, knowledgeable and diciplined people build those things.
The ability to remember trivial detials is not my concern at all. Most people think the ability to remember such things means you are "smart".
Since details change depending on the project. What I usually call a smart person is not a person who has a good memory but a person with common sense and knowledge of how things work.

So I need to screen candedites with questions that will expose their understanding and thought process, not memory or "smarts".

if you want to determine someone's technical competency, you need to have at least that same level of competency. based on the questions, and please don't take offense to this, you are not sufficiently competent to evaluate a network engineer's technical ability. if you like, i can go question by question and explain why the question is bunk, but i don't think that's what you are looking for.

as simon said, ask them about the networks they ran, the setups they put in place, what they would do differently if they had to do it over, what their favorite project was etc. put together a few tecnically interesting scenarios and ask for thoughts on implementation. you obviously need to know enough to understand what they are saying, come up with the scenarios and figure out whether their solutions are valid. i sugggest finding an impartial network engineer to help you with the interview, otherwise you will have to rely on past experience and references. *never* go by the certifications and *never* ask questions that can be answered by memorizing a CCxx study book - you want a guy who has been there, done that and has worn that same t-shirt since.

paul

Originally posted by rusko
if you want to determine someone's technical competency, you need to have at least that same level of competency. based on the questions, and please don't take offense to this, you are not sufficiently competent to evaluate a network engineer's technical ability. if you like, i can go question by question and explain why the question is bunk, but i don't think that's what you are looking for.

as simon said, ask them about the networks they ran, the setups they put in place, what they would do differently if they had to do it over, what their favorite project was etc. put together a few tecnically interesting scenarios and ask for thoughts on implementation. you obviously need to know enough to understand what they are saying, come up with the scenarios and figure out whether their solutions are valid. i sugggest finding an impartial network engineer to help you with the interview, otherwise you will have to rely on past experience and references. *never* go by the certifications and *never* ask questions that can be answered by memorizing a CCxx study book - you want a guy who has been there, done that and has worn that same t-shirt since.

paul


Thanks Paul. I don't mean to ask too much of your time but I would actually really appreciate it if you could pick apart my questions 1 by 1 and tell me why they are bunk. It's a learning process for me.
Also, I really agree that questions should not be asked that can be found in a CC** exam. I'm so tired of candedites with book knowledge. I experience and so on, not memorized details.

I have to add though that book knowledge is important when building up fundamentals but that's it.

Paul,
Are you going to pick apart my questions or what?
I'm looking forward to some constructive criticism

Yes, an interview is also a place to measure their skills, but what matters to you more? Being able to answer your pop quiz, or having diploma's and previous experience in the field?

Originally posted by Amdac
Yes, an interview is also a place to measure their skills, but what matters to you more? Being able to answer your pop quiz, or having diploma's and previous experience in the field?

Diploma's and previous experience is what any employer desires. But how can I tell if they really have previous experience? So many people put BS on the resume. So you need to qualify them. Measure them up.

Originally posted by appolo
But how can I tell if they really have previous experience? So many people put BS on the resume.

That's what references are for. Call them up. I'd always take real life experience over being able to pass a pop quiz.

Originally posted by Amdac
That's what references are for. Call them up. I'd always take real life experience over being able to pass a pop quiz.


I like your answer.

For this type of position, I think behavioral interviewing is best. You can get the answers to most of your questions and predict future performance by asking about past situations. Anyone can memorize information, but real life past experinces will tell you much more about the person's abilities.

http://www.quintcareers.com/behavioral_interviewing.html