Network Consulting Engineer Interview Questions
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Network Consulting Engineer interview questions shared by candidates
Explain the difference between TCP and UDP
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That's really as difficult as it gets?
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UDP packet processing is faster compared to TCP packet processing. This is because once TCP packets are delivered to the destination, an acknowledgement is expected at the transmission end. If no acknowledgement is received, re-transmission of packets occurs at the transmission end. This is opposite to UDP operation, in which no acknowledgement is necessary. Less
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TCP is a reliable protocol that utilizes windowing and acknowledgement packets to ensure all traffic is transmitted and received UDP is an unreliable protocol that does not utilize windowing and acknowledgements, and is good to use when you can't re-transmit a packet (EG a voice or video packet) Less
What are MAC addresses?
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For computers to identify each other on the data link layer, they need a MAC address (hardware address). All devices on a LAN must have a unique MAC address. A MAC address is a 48-bit (six octet) address burned into a network interface card. The first three octets (24 bits) of the MAC address indicate the vendor that manufactured the card. This is called the Organization Unique Identifier (OUI). The last three octets of the MAC address are the unique host address. An example of a MAC address is 00-80-C6-E7-9C-EF. Less
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MAC address is port address or physical address of hardware
What are some of the problems that you have solved in your career.
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The key in these questions is to cover the fundamentals. There's usually a back-and-forth with the interviewer. Might be worth doing a mock interview with one of the Cisco Network Consulting Engineer experts on Prepfully? They give some real-world practice and guidance, which is pretty helpful. prepfully.com/practice-interviews Less
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Well once in several of our WAN routers(Enterprise external to firewwall but before perimeter) there was a high CPU utilization issue during peak hours upto 99% levels. We looked at the logs and did debugs but the problem wasn't apparent. We opened a Cisco TAC case and were asked to run a battery of commands and the problem was still not giving. I decided to do some embedded packet captures and dedicated a full 12 hour shift to Wireshark output reading from a specific router and there were many types of traffic flowing through! I closely studied it and narrowed down the problem to netflow logging to an external server that constantly interrupted the CPUs. I went ahead and decided to sample them, or log externally only 1 in 200 packets and the peak levels got down to about 75-80%. I went ahead and requested the latest platform of router that did such processing in dedicated hardware modules and the CPU problem was history! **Note that I might be tentatively onto the position as they have moved forward to doing a background investigation and are in the middle of the processs so I would have to say No below on the offer as we are not yet there** Less
What is carrier sense multiple access collision detect (CSMA/CD)?
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CSMA/CD stands for carrier sense multiple access/ collision detection used ro detect collision in ethernet. before it sends any request it will verify whether the medium is free or not . if its free then it will send data otherwise it will wait for some time until the medium gets free and then it sends the data...this leads to avoid collisions in the medium Less
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SMA/CD describes the Ethernet access method. In CSMA/CD, many stations can transmit on the same cable, and no station has priority over any other. Before a station transmits, it listens on the wire to make sure no other station is transmitting. If no other station is transmitting, the station transmits across the wire. CSMA/CD is all about devices taking turns using the wire. Less
Why Cisco?
2 Answers↳
Learned about company culture.
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The key in these questions is to cover the fundamentals. There's usually a back-and-forth with the interviewer. Might be worth doing a mock interview with one of the Cisco Network Consulting Engineer experts on Prepfully? They give some real-world practice and guidance, which is pretty helpful. prepfully.com/practice-interviews Less
Why are manhole covers round?
2 Answers↳
Only shape that can't fall in the hole
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I don't know, ask someone at Mimcrosoft.
How do you think you did in the technical interview? This question is great for testing self-awareness and a candidate's willingness to discuss possible weaknesses or blind spots.
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I was honest and said I didn't think I performed very well given I was coming from a very different field. I demonstrated that I could learn quickly and would continue to do so in the job, but recognized that my networking knowledge was not very strong at that point. Less
Round 1 was split into 20 apti stuff , 10 problem solving stuff and 20 tech stuff, which further can be drilled down as 10 from Micropocessors , Networking etc and rest 10 from usual programming on C , C++ and Java Round 2 was basic technical round where in I was asked about the OSI Layers , Difference between routing and switching , MAC Addr and IP Addr , and explain the full process of how a packet is moved from source to destination including DNS Lookup , Routing protocols that I would suggest etc etc . I personally suggest "Computer Networking A top down approach" 6th Edition by Kurose and Ross would be the best book . Round 3 was the most rigorous HR round I have ever been in ; The panel consisted of 2 men ; Since this is for a role that Cisco would use to face a customer mostly they were all management oriented questions , The interviewer asked me a few tech questions until I ran out of answers and asked me what would I do If the same thing happens on a presentation with the customer . I was not confident enough to tell him I would ask some time and get back with the answers ASAP . The HR was just expecting a confident reply from me . so what I would suggest is to reply confidently even if you are with the wrong answer tell him that I am not sure of this answer but I will get back with the right ones ASAP . Never go for a HR round unexpectedly , stay cool , know when your turn would probably come and never panic or get nervous in an HR round . All your efforts on clearing the first few rounds would go to drain if you flunk in the Final HR Round . So whatever condition you are get back to normal , keep smiling & be confident and you can easily crack Cisco Systems for sure .. All the best ..!!
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Though I did not get a offer I got hell a lot of experience and exposure in attending such a HR round . I would sincerely like to thank the two gentle men who conducted the interviews for me . And one more important thing to note is " At the EOD it's all pure luck and your condition at that moment deciding the offer you get " Less