Cisco Cisco IOS Software Release 12.3(8)T 릴리즈 노트

This section provides analysis of reliability/availability of the SSG on the MWAM in the Catalyst 
6500/Cisco 7600 chassis in context with other Cisco features. The following features are considered:

SSG on MWAM

Five SSGs on each MWAM

Multiple MWAM cards installed in one chassis

RLB on Supervisor module

Distributes traffic load among SSGs

Provides SSG switchover

FWLB on Supervisor module or CSM—Provides the return traffic path through the same SSG that 
forwarded the service request

The Server Load Balancing (SLB) function can be implemented in the Supervisor module to provide 
RADIUS Load Balancing (RLB) across the SSGs on one or multiple MWAMs. The Content Switching 
Module (CSM) can be used to provide Firewall Load Balancing (FWLB). 

While the RLB and FWLB features are not part of the SSG-MWAM Release 1.2, they are described here 
to demonstrate their use in mobile wireless solutions that include MWAM-based SSGs.

The RLB feature is implemented in the Supervisor module. The RLB feature provides one virtual IP 
address for all users accessing services and keeps the list of real IP addresses of all SSGs. The RLB 
feature distributes the upstream traffic between SSGs by using the load-balancing mechanism. It keeps 
the information about SSG assignment for each user session. When the RLB detects an SSG failure, it 
directs traffic to another available SSG. 

The FWLB feature ensures that the downstream traffic to the user is sent to the same SSG that handled 
the upstream traffic. The FWLB feature tracks all upstream traffic from an SSG to a network server and 
links the SSG address with the user session. This information is used when the downstream traffic from 
the server is received. The FWLB feature determines which SSG is handling the user traffic. 

The FWLB feature can be implemented in the CSM in the same chassis or in the Supervisor module in 
different chassis.