Are you looking for job as a network operations engineer? Or are you thinking of leaving your current position for a new job as a “manager: network operations” with a new company?

If you answered “Yes” to either of those questions, then this article is a must read for you and any of described technologies and questions may be asked of you during the interview!

An Introduction to Network Operations Manager/Engineer Roles and Responsibilities:

Nowadays, every business is running on the shoulder of a computer network or third-party cloud deployments and managing today’s complex hybrid IT infrastructure is a tough job; both private and public cloud infrastructure creates complexity for IT services to run and operate. The network operations engineer ensures flawless installation activities and routine troubleshooting of network infrastructure to maintain the maximum possible service availability and performance.

A network operations engineer/manager must have moderate to excellent understanding of networks and systems. Network operations engineers often escalate issues in a hierarchic manner; in case an issue is not resolved by a given deadline, the next level will be used for problem remediation. Their job roles often involve 24×7 support for network services with both planned and unplanned work shifts.

Network operation centers sometimes have multiple levels of engineers, which shows the experience and skillset of a NOC engineer. For example, a newly hired NOC engineer might be considered a “level 1,” whereas an engineer who has several years of experience may be considered “level 2” or “Level 3”. A network operations manager/engineer is responsible for performing the following functions:

  • Ensuring stable and reliable network services of access and core networks
  • Effective analysis of network visibility and availability
  • Network performance monitoring and reporting
  • Incident response and review of network’s issues
  • Installation and maintenance of network monitoring, analysis and reporting tools
  • Evaluating recommendations to resolve network issues
  • Researching and learning new technologies adopted by the clients
  • Technical interaction with higher management, vendors, and clients
  • Installation of network hardware and software

Required Key Skills for a Network Operations Manager/Engineer:

Strong analytical and subjective skills, along with the following knowledge set:

  • Understanding of network architect designing and managing LAN, WAN, and VoIP networks
  • Sound knowledge of network-layered approach
  • Good understanding of multi-vendor network devices such as Cisco, HP, Juniper, Nortel, etc.
  • General understanding of hardware network devices installation
  • General understanding of networking IOS (IOS, IOS-XE, IOS-XR, NX-OS)
  • Knowledge about network management/ analysis/ monitoring tools
  • General understanding of rollback and failovers handling
  • Ability to handle multiple assignments with deadlines
  • Able to communicate network issues effectively and in a comprehensible manner with clients and team members

My Best Questions for an Interview of Network Operations Manager/ Engineer

All of the questions below are very common and must be well prepared for before facing any interview for the management/engineering position in network operations and be honest and confident while answering.

Most interviews for NOC positions start with common questions such as:

“Tell me something about yourself”

“Questions related to current/previous job roles”

“How can you handle a team of engineers?”

“What are your major strengths and weaknesses?”

“How do you find your qualification and experience as a NOC manager?”

“Share some of your achievements as a network professional?”

“What is your salary expectation for this position?”

While answering about current/previous job role, don’t forget to mention
your responsibilities with recent activities and achievements. Apart from above HR/ Personal questions, let’s discuss some important technical questions as well.

Q. Describe some of network tools you are familiar with.

A. This is one of the most common questions asked during the management/engineering position in network operations, so this question must be prepared for before facing the interview. Here you can share the list of tools you have worked with and you can even provide the name of your known network tools. You should consider our recently published articles on network tools:

http://resources.intenseschool.com/top-10-network-management-tools/

http://resources.intenseschool.com/top-10-network-analysis-tools/

http://resources.intenseschool.com/top-10-network-security-tools/

http://resources.intenseschool.com/top-10-network-scanning-tools/

http://resources.intenseschool.com/top-7-network-troubleshooting-tools/

Q. How to troubleshoot a high CPU utilization problem in a router?

A. This symptom is the sign of abnormal functionality in a router. First we should know the exact reason for increased CPU utilization, and we can use “show processes cpu ,” “show interface stat” commands to check the process utilizations. It could be due to high traffic flow (congestion), complex ACL or VPN deployments, ARP/TCP issues etc. To know more, visit the following links:

http://www.cisco.com/c/en/us/support/docs/routers/10000-series-routers/15095-highcpu.html

http://www.cisco.com/c/en/us/support/docs/routers/7500-series-routers/41180-highcpu-processes.html

Q. If a router’s WAN link goes down, what you will do in that situation?

A. First we need to verify the exact reason for failover; it could be due to physical or protocol issues. If it is a “protocol down” problem, then valid reasons could be link authentication failure, encapsulation mismatch, clock rate not configured, improper access control, MTU or Duplex mismatch, etc. For more information visit the following web page:

http://www.cisco.com/en/US/docs/internetworking/troubleshooting/guide/tr1915.html

Q. Is it normal to get CRC errors on MPLS WAN links?

A. It could be normal if it is less than 1% of total traffic on that interface with no packet drop

And it is recommended to resolve link issues in case cyclic redundancy check (CRC) errors are more than 1% of the total interface traffic. The most common reason for receiving CRC errors is the duplex setting, as most of providers set their interface to “auto” mode.\

Q. if a router’s WAN link goes down, we are not getting any alert or notification. What could be the issue?

A. Proper syslog or SNMP configuration is required to get the alerts of a link failure. For advanced alert or notification management, network management tools can be configured to track such kind of alerts.

Q. What will happen if one of the ports goes down of an 8 port EtherChannel?

A. The overall bandwidth of an EtherChannel interface depends on its active member links. An EtherChannel with 8 active 100 Mbps links should indicate a bandwidth of 800 Mbps and, if one of its physical ports fails, the available bandwidth of port-channel interface will be evaluated as 700Mbps without flapping the port-channel.

Q. How to perform password recovery in a switch?

A. Every switch series has its own set of recovery methods. Here you can describe the procedure of password recovery for the switches on which you have shown your work experience. You can also refer following links to get an idea of password recovery on well-known Cisco switches.

http://www.cisco.com/c/en/us/support/switches/catalyst-2960-series-switches/products-password-recoveries-list.html

http://www.cisco.com/c/en/us/support/switches/catalyst-3750-series-switches/products-password-recoveries-list.html

http://www.cisco.com/c/en/us/support/switches/catalyst-4500-series-switches/products-password-recoveries-list.html

http://www.cisco.com/c/en/us/support/docs/switches/catalyst-6000-series-switches/14981-pswdrec-6000IOS.html

Q. How to access a layer 2 switch from a remote location?

A. To access a layer 2 switch remotely, a management SVI (switch virtual interface) is required with proper Telnet/SSH access and IP address of SVI must be reachable.

Q. What is the significance of the variable IP-OSPF-Transmit-Delay?

A. If OSPF is configured on low bandwidth links, IP-OSPF-Transmit-Delay is used to increase the time of the age field of a LSA update. By default it is set to 1 second and, to make it effective, it must be added before transmission over a link.

Q. What does “%OSPF-5-NBRSTATE: ospf-1 [5330] Process 1, Nbr 10.3.3.14 on Vlan44 from FULL to EXSTART, BADSEQNUM OSPF” log message mean?

A. This log message pops up when an OSPF DBD exchange process uses a bad sequence number (due to packet loss or packet exploitation) for the synchronization of the database with its neighbors.

Q. If my BGP neighbor is stuck in idle, or active state, what should I do?\

A. If BGP peer is in idle state then it could be due to physical connectivity failure or neighbor is not defined with properly with respective AS. In connect state, BGP tries to establish TCP session over port number 179 if it fails to establish TCP connection then it goes to Active state where it retries to establish TCP connection. By using debug ip bgp and debug ip tcp transactions commands, we can find out the exact cause of TCP connection failure. Lack of “update-source” or “ebgp-multihop” command can also be a reason for neighbor active state; to learn more visit the following link:

http://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/13752-24.html

Q. How to resolve a BGP neighbor issue while receiving “hold time expired” notification message?

A. This log message is common when a BGP peer flaps. If reachability breaks or fluctuates to a defined BGP neighbor, then it goes down, but after the hold time expires. To resolve this problem, you will need to fix BGP peering; possible issues could be due to MTU, unicast drop, SP circuit down, or misconfiguration under BGP process.

The questions above are very collective and important from the standpoint of clearing an interview for a NOC engineer/manager position. It is not possible for anyone to explain all kinds of questions, but you can get more frequently asked interview questions for network operation’s jobs from the download link posted here. If you find any difficulty in answering any question, then you can write me @ comment section.

Before facing any Interview, a candidate should take care of following points;

  • A quick recap of relevant technologies
  • Read your resume throughout and detail your strength/weaknesses, achievements, and prior job roles and responsibilities
  • Professional certifications allow the interviewer to understand your knowledge level, so point out your certifications (if you have any)
  • Updated LinkedIn profile helps you a lot to get job recommendation and referrals for your desired job roles

This article is the output of my extensive research and work experience, and my team, corporate clients, and colleagues helped me a lot to develop this article. With this article, I am trying to help/guide candidates about interview preparation for getting an engineering or management position in the field of network operations.

I hope this article will be appreciated so that I will be able to offer more in this segment. You can write me @comment section below for providing any query/feedback; I will try my best to resolve your queries at the earliest. And don’t forget to spread the link of this article on your Facebook, Twitter, and LinkedIn accounts so the maximum of people can get this exclusive piece of information. Keep reading @ Intenseschool.com and consider joining our Facebook group, http://www.facebook.com/intenseschool, to get updates on new posts and technologies.