The CPS solution is a robust and
scalable software-based solution that can be expanded by adding additional
hardware and software components. The following sections explain typical
scenarios of when to expand the hardware and software to effect such growth.
When Expansion is Necessary
Your network may grow for the
The subscriber base has grown or
will grow beyond the initial installation specifications.
In this case, the number of active or non-active subscribers becomes
larger than the initial deployment. This can cause one or more components to
reach capacity. New components must be added to accommodate the growth.
The services or subscriber scenarios have changed, or new services
have been introduced, and the transactions per second on a component no longer
When a new service or scenario occurs, often there is a change in
the overall Transactions Per Second (TPS), or in the TPS on a specific
component. When this occurs, new components are necessary to handle the new
The operator notices that there are factors outside of the initial
design that are causing either the overall system or a specific component to
have a high resource load.
This may cause one or multiple components to reach its capacity for
TPS. When this occurs, new components are necessary to handle the new factors.
Hardware Approach to
Adding a new component
may require adding additional hardware. However, the addition of more hardware
depends on the physical resources already available, plus what is needed for
the new component.
When adding more hardware, the design
must take into consideration the high availability (HA) needs of the system.
The HA design for a single-site system is N+1 at the hardware and application
level. As a result, adding a new blade incrementally increases the HA capacity
of the system.
For example, in a basic installation there are 2 Cisco Policy Server
blades handling the traffic. The solution is designed so that if one of the
blades fails, the other blade can handle the entire capacity of the system.
When adding a third blade for capacity expansion, there are now 2 blades to
handle the system load if one of the blades fails. This allows for a more
linear scaling approach because each additional blade can be accountable for
being able to use its full capacity.
When adding new blades to a cluster, the blades in the cluster must
be co-located to achieve the proper throughput between other components.
Adding a New
Install ESX server to the
Open the CPS Deployment
Template spreadsheet. This spreadsheet should have been created and maintained
during the initial deployment.
In the Additional Hosts sheet,
add an entry for the new ESX server with IP, Host name and Alias.
Save the CSV file and transfer it to the following directory on
the Cluster Manager /var/qps/config/deploy/csv
to convert the csv to json.
Component (VM Node)
Approach to Expanding
The most common components to be
expanded are on the Cisco Policy Servers. As your system begins to scale up,
you will need to add more CPS nodes and more SessionMgrs. Expansion for other
components can follow the same pattern as described here. The next sections
discuss the configurations needed for those specific components to be active in