Network engineer interview questions

1. Describe OSPF in your own words.
2. SPF areas, the purpose of having each of them
3. Types of OSPF LSA, the purpose of each LSA type
4. What exact LSA type you can see in different areas
5. How OSPF establishes neighboor relation, what the stages are
6. If OSPF router is stucked in each stage what the problem is and how to troubleshoot it
7. OSPF hierarchy in the single or multi areas. Cool OSPF behavior in broadcast and nonbroadcast
8. Draw the diagram of typical OSPF network and explain generally how it works, DR, BDR, election, ASBR, ABR, route redistribution and summarization

STP - Spanning Tree Protocol

1. How it works and the purpose
2. Diff types (SSTP, MSTP, RSTP) Cisco - PVST/PVST+
3. root election
4. Diff. port stages and timing for convergence
5. Draw the typical diagram and explain how diff types of STP work
6. What ports are blocking or forwarding
7. How it works if there are topology changes

1. What are they
2. Diff types
3. Write an example if you want to allow and to deny…
4. Well-known port numbers (DNS - 53 and etc…)

1. What is that
2. What is the diff b/w L2 and L3 QoS
3. How it works

1. Draw the typical network diagram you have to deal with
2. explain how it works
3. What part of it you are responsible
4. firewall, what is that, how it works, how it is diff from ACLs
5. What problems with the network you had had and how you solved it.
6. What are the ways to troubleshoot the network, techniques, commands
7. network security, ways to achieve it

1. VLANs
2. STP
3. How a L2 switch works with broadcast, unicast, multicast, known/unknown traffic
4. VRRP, GLBP
5. port monitoring and mirroring
6. L3 switch, how it works
7. PIM sparse and dense modes