This article explains some of the definitions that can be found when running the command "show chassis environment"

• NW-PFE: Temperature of the Packet Forwarding Engine (PFE) located in the northwest corner of the board. This component handles high-speed packet processing and forwarding.
• SE-PFE: Temperature of the Packet Forwarding Engine (PFE) located in the southeast corner of the board. It's likely a separate PFE for redundancy and load balancing.
• PHY-4/5: Temperature of the physical layer (PHY) components responsible for transmitting and receiving data on ports 4 and 5. These could be integrated circuits or modules.
• MGMT PHY: The MGMT PHY is dedicated to the management interface, ensuring its health and functionality even when other network operations are impacted. Temperature of the PHY component associated with the management interface, used for out-of-band management access.
• NW/SE Corner Components: While the exact components in the NW/SE corners might vary, they often house power supplies (PS), cooling fans, or additional PFEs for redundancy and performance.
• PHY Components: The PHY components typically handle the physical layer of Ethernet communication, converting signals between the switch's internal logic and the physical copper or fiber connections.