Cisco Cisco IOS Software Release 12.2(18)SXE

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Benefits
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Cisco IOS Release 12.2(18)SXE
Stateful Backup of Redundant Route Processors
When used with RPR+, IOS SLB supports the stateful backup of redundant route processors for CMX 
for Catalyst 6500 family switches and Cisco 7600 series routers. This enables you to deploy Cisco 
Multiprocessor WAN Application Modules (MWAMs) in the same chassis as IOS SLB, while 
maintaining high availability of load-balancing assignments.
Flow Persistence
Flow persistence provides intelligent return routing of load-balanced IP flows to the appropriate node, 
without the need for coordinated hash mechanisms on both sides of the load-balanced data path, and 
without using Network Address Translation (NAT) or proxies to change client or server IP addresses.
Benefits
IOS SLB shares the same software code base as Cisco IOS and has all the software features sets of 
Cisco IOS software. IOS SLB is recommended for customers desiring complete integration of SLB 
technology into traditional Cisco switches and routers.
On Cisco Catalyst 6500 family switches, IOS SLB takes advantage of hardware acceleration to forward 
packets at very high speed when running in dispatched mode.
IOS SLB assures continuous, high availability of content and applications with proven techniques for 
actively managing servers and connections in a distributed environment. By distributing user requests 
across a cluster of servers, IOS SLB optimizes responsiveness and system capacity, and dramatically 
reduces the cost of providing Internet, database, and application services for large-, medium-, and 
small-scale sites.
IOS SLB facilitates scalability, availability, and ease of maintenance:
The addition of new physical (real) servers, and the removal or failure of existing servers, can occur 
at any time, transparently, without affecting the availability of the virtual server.
IOS SLB's slow start capability allows a new server to increase its load gradually, preventing failures 
caused by assigning the server too many new connections too quickly.
IOS SLB supports fragmented packets and packets with IP options, buffering your servers from 
client or network vagaries that are beyond your control.
IOS SLB firewall load balancing enables you to scale access to your Internet site. You can add 
firewalls without affecting existing connections, enabling your site to grow without impacting 
customers.
Using DFP enables IOS SLB to provide weights to another load-balancing system. IOS SLB can act as 
a DFP manager, receiving weights from host servers, and it can act as a DFP agent, sending weights to 
a DFP manager. The functions are enabled independently—you can implement either one, or both, at the 
same time.
Administration of server applications is easier. Clients know only about virtual servers; no 
administration is required for real server changes.
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. Additionally, though it does not eliminate the need for a firewall, 
IOS SLB 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.