One-armed route-path
From LB Wiki
One-armed configurations are probably the most common configuration in SMB setups, and the second most common in the Enterprise market.
Characteristics of a One-armed, route-path configuration:
- The Virtual Server and Real Server IPs are on the same subnetwork
- Only one interface on the load balancer is used
Benefits of One-armed mode
- The primary benefit is the ease in which a load balancer can be put into an existing infrastructure. It doesn't require you to re-IP, all it requires is an extra IP address to give the load balancer as a VIP.
Drawback of One-armed mode
- If you need to use the load balancer to restrict access to the real servers (as a make-shift firewall), then one-armed mode probably isn't the best choice (two-armed mode would be).
- Also, because traffic traverses the load balancer's single interface twice, you effectively halve the amount of throughput you can achieve out of an interface. For instance, with Fast Ethernet, the most traffic you could push to the Internet would be 50 Mbps (on a full-duplex connection).
Inbound with one-armed, route-path
Inbound traffic is directed to the load balancer through a virtual IP address, which is separate from the IP addresses of the real servers. On the way out, traffic is directed back through the load balancer in one of two ways:
- The load balancer is the default gateway for the servers
- The load balancer uses non-transparency, which causes all connections to the server appear to come from the load balancer. The servers simply reply directly to the load balancer.
Outbound with one-armed, route-path
