I first applied for the role. Then the HR person emailed me saying she would like to do an initial assessment with me, so I had to book time. When she did call, she asked questions like how much I knew about the company and why I wanted to work for Cisco Meraki. Then she went on to ask basic networking questions like describing STP, what it's for ? And explaining VLANs. And to describe how devices get an IP address, whether if it's statically configured or dynamically via DHCP, then explain the entirety of the DHCP process.
Another question she asked was about Address Resolution Protocol (ARP), the entire process from which the hosts communicates with another host on the same network; if the IP address of the recipient is not on the ARP table of the host, then how it sends an ARP query frame as broadcast and how the other host responds to it. So the source host gets the IP address.
After that interview, sometime later, I got an email from her, telling me that I was successful to progress to the next stage via WebEx. This was more difficult though, but could be aced if you understand CCNA. The first question, was a very basic STP question, with 3 switches, was asked which one becomes the root bridge, and which port gets blocked, determined by Bridge ID.
The following question, she draws a topology, of a switch with 2 hosts connected to it, each being on a separate VLAN, and that switch is connected to a router. First question is, how do the two hosts communicate ? It's a router-on-stick question, And if they cannot communicate, then what steps would you take to ensure they are able to communicate ? Ensure the hosts have an IP address (statistically or dynamically). Then ensure the switch ports (connected to hosts) are on Access mode, with their allowed VLAN configured. Then ensure the default gateway of each VLAN on the switch is set to subinterfaces(s) of the router's interface. Next step would be, to ensure the switch port connecting to the router is configured as a trunk, that allows the 2 VLANs to travel over. Make sure the native VLAN of that trunk does not clash with one of the VLANs. Then on the router. Look at the physical interface which is connected to the switch port. Ensure that port is administratively & operationally up/up. Ensure it has an IP address. Then check if it has subinterfaces, and ensure each sub interface is encapsulated with dot1q with the VLAN with an IP address acting as the default gateway for each of the VLANs (specified on the switch). By this point, the troubleshooting for this Router-On-Stick should be done, unless I missed a step.
Another question, was, to go through the process of a frame travelling from one host to another, what changes along the way, we know the IP address of source & destination remains the same, but the source/destination of the MAC addresses changes after each point, from the host to the router, then from the router to the destination host.
Next part is, a DHCP server is added onto the topology, and a new host. And the new host is set to dynamically get it's IP address from this DHCP server. Explain the entirety of the DORA process. Then you're told that the DHCP pool consists of IP Addresses of a particular range, and the IP address of the new host is not of that range, therefore the IP address must have been got from a rogue DHCP server. How would you go about this issue ? This part I could not do.
There was a question on how the switch populates it's CAM table (MAC Address table), which is when a frame enters a switch via a port, the switch looks at the frames' source address and attaches that MAC address to that ingress port. The binding between the Mad Address & port is 300 seconds by default (5 minutes).
Sorry if I missed a question from this, interview.
After this interview, I had an email from the same HR lady, telling me I passed the interview. And that I had to sit a third one. When the time came for me to sit this one, I ended up failing it.
There are 2 main topologies, one with wireless, the other with VPN.
The wireless one is, when 2 AP's are connected to a switch, and that switch is connected to another switch, which is connected to a DHCP server. Each of the AP's are in separate locations (maybe different rooms). In each location, there exists a host, both cannot connect to their AP's. How would we go around this issue for each of them to connect to the AP. And after that, how would we go about troubleshooting issues for each of the devices to get an IP address ? I'd make sure hosts are connected to correct SSID and passwords are same. If the devices are connected to the AP's by then. Then configure the hosts to dynamically get the IP addresses from the DHCP server. Then make sure the switch ports connecting the two switches are configured as trunks with their allowed VLANs being able to transverse through the link, and removing inconsistencies regarding the native VLANs.
