Cisco Systems 78-11741-02 manual IOS SLB Functions and Capabilities, IPC-134

Configuring Server Load Balancing

IOS SLB Functions and Capabilities

Security of the real server is provided because its address is never announced to the external network. Users are familiar only with the virtual IP address. You can filter unwanted flows based on both IP address and TCP or UDP port numbers. Though it does not eliminate the need for a firewall, IOS SLB also can help protect against some denial-of-service attacks.

In a branch office, IOS SLB allows balancing of multiple sites and disaster recovery in the event of full-site failure, and distributes the work of load balancing.

Figure 23 illustrates a logical view of IOS SLB.

Figure 23 Logical View of IOS SLB

	Virtual server
Real	Real	Real
server	server	server

Catalyst 4840G with IOS SLB

Client

Client

29164

Client

Client

IOS SLB Functions and Capabilities

Functions and capabilities supported in IOS SLB are described in the following sections:

•Algorithms for Server Load Balancing

•Port-Bound Servers

•Client-Assigned Load Balancing

•Content Flow Monitor Support

•Sticky Connections

•Maximum Connections

•Delayed Removal of TCP Connection Context

•TCP Session Reassignment

•Automatic Server Failure Detection

•Automatic Unfail

•Slow Start

Cisco IOS IP Configuration Guide

IPC-134