Networking

DHCP Relay Across Multi-VLAN Subnets

Network Design diagram · made in Skemio

Network diagram illustrating client devices broadcasting on separate VLAN switches, routed via an L3 core switch DHCP relay to a central DHCP server.
Network diagram illustrating client devices broadcasting on separate VLAN switches, routed via an L3 core switch DHCP relay to a central DHCP server.
Open it in SkemioMake your own

What it shows

  • L3 switch intercepts broadcast DHCP Discover packets on local access VLANs
  • Relay agent injects GIADDR subnet IP and unicasts packet to central server
  • Central DHCP server matches pool to GIADDR and replies directly by unicast

The takeaway

DHCP relay eliminates redundant local servers by converting VLAN broadcasts into routed unicast traffic.

More network design diagrams