1. Routed Mode:

• Load balancer acts as a Layer 3 switch (uses IP addresses to forward traffic)
• All servers are connected to the load balancer (or through a Layer 2 switch)
• Isolates the subnet from larger network, more secure

2. One-arm Mode:

• Load balancer is attached to switch with one port
• Servers can communicate with clients without going back through load balancer
• Avoids unnecessary traffic, maximizes performance

3. Transparent Mode:

• Load balancer acts as a Layer 2 switch (uses MAC addresses to forward traffic)
• All servers are connected to the load balancer (or to a Layer 2 switch )
• Less intrusive - requires little change to existing network infrastructure

4. Direct Server Return (DSR):

• Allows the server to return traffic directly to the client
• Real servers and load balancers must reside in the same Layer 2 domain
• Reduces overhead on the load balancer by reducing traffic load