Cisco Cisco IOS Software Release 12.2(14)ZA

Connectionless Secure WSP

Connectionless WSP

Connection-Oriented Secure WSP

Connection-Oriented WSP

IOS SLB provides RADIUS load-balancing capabilities for RADIUS authentication, authorization, and 
accounting (AAA) servers.

IOS SLB provides the following RADIUS load-balancing functions:

Balances RADIUS requests among available RADIUS servers and proxy servers.

Routes RADIUS request retransmissions (such as retransmissions of unanswered requests) to the 
same RADIUS server or proxy server as the original request.

Provides session-based automatic failure detection.

Supports both stateless backup and stateful backup.

In addition, IOS SLB can load-balance devices that proxy the RADIUS Authorization and Accounting 
flows in both traditional and mobile wireless networks. For more information, see the 

.

IOS SLB can balance RealAudio and RealVideo streams via Real-Time Streaming Protocol (RTSP), for 
servers running RealNetworks applications.

IOS SLB can balance Virtual Private Network (VPN) flows, including the following flows:

IP Security (IPSec) flows. An IPSec flow consists of a UDP control session and an ESP tunnel.

Point-to-Point Tunneling Protocol (PPTP) flows. A PPTP flow consists of a TCP control session and 
a GRE tunnel.

An IOS SLB device can represent a single point of failure, and the servers can lose their connections to 
the backbone, if either of the following occurs:

The IOS SLB device fails.

A link from a switch to the distribution-layer switch becomes disconnected.

To reduce that risk, IOS SLB supports the following redundancy enhancements, based on HSRP: