The IP addresses of the switch and the access network are different

Switches and access networks can operate on different IP addresses because switches primarily function at Layer 2, forwarding traffic based on MAC addresses, while IP addresses are assigned to devices for network communication and management purposes.

Switches and IP Addresses

Not all switches have IP addresses. Unmanaged switches do not require IP addresses as they simply forward traffic between devices without configuration . Managed switches, however, are assigned IP addresses—either statically or via DHCP—to allow administrators to configure, monitor, and manage the switch remotely . The IP address of a managed switch is primarily for management purposes and does not affect the forwarding of data between devices on different subnets .

Access Networks and Subnets

An access network typically refers to the subnet or LAN segment that connects end devices like PCs, printers, or access points. Each subnet has its own IP address range, and devices within that subnet receive IP addresses from a DHCP server, usually configured on a router . It is common for the switch's management IP to be in a different subnet than the devices it connects, especially in larger networks with hierarchical designs (core, distribution, and access layers), .

How Devices Communicate Across Different IPs

Even if the switch and the access network are on different IP subnets, devices can communicate because the switch operates at Layer 2, forwarding packets based on MAC addresses rather than IP addresses . Routing between subnets is handled by a router or Layer 3 switch, not the access switch itself . This separation allows network administrators to manage switches securely on a dedicated management subnet while keeping user devices on separate subnets.

Tracking Devices on Access Switches

To find the IP addresses of devices connected to a particular access switch, administrators often start at the router or Layer 3 switch using ARP tables to map IP addresses to MAC addresses. Then, by checking the MAC address table on the access switch, they can determine which port a device is connected to . Some modern Layer 2 switches support IP device tracking, which can auto-source IP addresses for ARP requests even if the switch itself has no IP configured .

Key Takeaways

• Switches forward traffic based on MAC addresses; IP addresses are mainly for management.
• Managed switches have IPs for configuration, while unmanaged switches do not .
• Devices in an access network get IPs from DHCP and may be on a different subnet than the switch's management IP .
• Communication across different IP subnets requires routing, not the switch itself .
• Device tracking and management can be performed using ARP tables and MAC address tables . This setup allows for secure, organized, and scalable network management, separating device traffic from administrative access.