What is the OSI model. Describe the OSI model and provide examples of the protocols exist in each layer. Layer 2: How does layer 2 work. What is the trunk protocol. Why do you need Vlans. Explain what is the spanning tree protocol and why it is used. How the root bridge is elected and what are the BPDUs. Layer 3: Why do you need routing protocols. What routing protocols do you know. Explain how the RIP protocol works. Explain how OSPF works. Why you cannot use OSPF to route traffic over the internet. Explain the BGP protocol. General questions: Tell us a difficult case you have worked on and how did you solve it. Why do you want to work for Cisco.
