Which of the following describes the roles of devices in a WAN?

Hello Anjali There would be many devices in a 'WAN' Network Topology performing functions from Layer-1 to Layer-3 at basic level and further Layers if additional services like security and QoS are needed. Layer-1 - Modems , CSU/DSU, Smart Jacks - These Terminate the ISP line at Customer End and help troubleshooting issues like link failures or errors on links from ISP to Customer. Layer-2 - Most of the times these are not at Customer End, example Frame-Relay Switch at ISP. Layer- 3 Routers these are critical devices for routing traffic in and out of a WAN /LAN , making decisions based on Routing Information Table Learned Dynamically from Routing Protocols or Manually through Network Admin. I hope these have answered your question. read less