F5 Test Engineer interview questions

Got initial call from the recruiter asked some basic behavioral questions. In the 2nd round got a call from hiring manager asked about application layer protocols and my project work

phone screen and then onsite with manager and three other senior engineers. network protocol, application layer mostly, puzzle question. no coding or basics of any programming language was asked.icmp, network security, explain your projects well.http in depth asked. stp,rstp,tcp headers