("Switches. Routers. Firewalls (2nd Edition)" introduces the most important hardware devices used to build networks - switches, routers and firewalls, covering principles, parameters, classification, application, planning, interfaces, and connections. It expresses and integrates the latest technology, latest equipment and latest application in many aspects, such as configuration, management, monitoring, and faults. This book has outstanding practicability and operability, with fluent and precise language expression, easy-to-understand theoretical explanation, detailed and appropriate specific operations, and emphasis on cultivating the ability to start and analyze. "Switch. Router. Firewall (2nd Edition)" is suitable for small and medium network administrators, as well as all network enthusiasts who are ready to engage in network management, and can be used as a teaching material for computer majors in colleges and universities.)