PCA Configurable Components

Key PCA configurable components include:

• PCA Binding Region Place Association consisting of all PCA Sites
• PCA Mated Sites Place Associations, each consisting of redundant PCA Sites
• Policy Session Resource Domains - one per PCA Mated Sites Place Association consisting of all session SBR server groups at the mated sites.
• Policy Binding Resource Domain - one per PCA Binding Region Place Association consisting of all binding SBR server groups.
• Policy and Charging DRA Resource Domains - one per PCA Mated Sites Place Association consisting of all DSR (multi-active cluster) server groups at the mated sites.
• SBR Server Groups - enough to handle the load in stack events per second.
• Diameter Signaling Router (multi-active cluster) Server Groups - one per PCA DRA Site.
• SBR Databases - PCA supports two types of SBR Database: SBR Binding Database, used by the P-DRA function of PCA, and SBR Session Database, used by both P-DRA and OC-DRA functions of PCA. An SBR Database is hosted by Policy and Charging SBR Server Groups assigned to either a Policy Binding Resource Domain or a Policy Session Resource Domain.
• SBR Database Resizing Plans - An SBR Resizing Plan is the configuration that identifies the SBR Database to be resized and the Target Resource Domain to which the SBR data will be migrated.
• SBR Data Migration Plans - An SBR Data Migration Plan is the configuration that identifies the Initial SBR Database that is the source of SBR data to be migrated and the Target SBR Database to which the SBR data will be migrated.

For multiple mated pair/triplet deployments, there are two different configurations for mated pairs:

• One mated pair/triplet that hosts the PCA Binding database and an instance of the Session database
• N mated pairs/triplets that each host only an instance of the Session database

Figure 3-5 illustrates two PCA DSR Sites configured as a Mated Pair:

• This Mated Pair hosts the PCA Binding database and an instance of the Session database.
• The SBR Database is configurable and contains a number of SBR Server Groups.
• Each SBR Server Group consists of 3 servers using the Active/Standby/Spare redundancy model, allowing for Site redundancy.
• The number of SBR Server Groups necessary to host the binding or session database will be determined by the application provider prior to feature activation based on expected policy signaling needs. The number of SBR Server Groups is configured in the SBR Database and can be increased or decreased as needed.
• Each Site has an SOAM Server Group consisting of 3 servers using the Active/Standby/Spare redundancy model, allowing for Site redundancy.
• The PCA network has an NOAM Server Group consisting of 2 servers using the Active/Standby redundancy model. If NOAM site redundancy is desired, another pair of Disaster Recovery NOAM servers can be deployed at a different Site.
• Each Site has a number of DA-MP servers sufficient to carry the desired Diameter signaling load.
• Each Site has two pairs of IPFE servers – one for use by Policy Clients and one for use by PCRFs. (IPFE is not required.)

Figure 3-5 Example PCA Mated Pair - Hosting Binding SBRs

Figure 3-6 illustrates a possible configuration for additional mated pairs that do not host the Binding database:

• Each subsequent mated pair deployed after the set of mated pairs hosting the Binding database will host only an instance of the Session database (no Binding database).
• The number of DA-MPs can vary depending on the expected Diameter signaling load.

Figure 3-6 Example PCA Mated Pair - Not Hosting Binding Policy SBRs

Figure 3-7 illustrates example relationships between PCA DSR Sites and Policy Clients and PCRFs:

• Each PCA DSR Site has a set of Policy Clients whose primary connection is directed to that PCA.
• Each PCA DSR Site has a set of PCRFs to which it distributes new bindings. Each PCRF at this Site has a primary connection to the PCA DSR at that Site.
• Each policy client should have a secondary connection to the mate of the PCA DSR for which it has a primary connection. (Without this cross-connect, PCA site failure would leave the Policy Client with no access to any PCRF.)
• Each PCRF should have a secondary connection to the mate of the PCA DSR for which it has a primary connection. (Without this cross-connect, PCA site failure would leave the PCRF inaccessible.)
• Each Mated Pair of PCA DSRs shares an instance of the Policy Session database.
• All PCA DSRs share the Policy Binding database, conceptually in the middle of the network.
• If Diameter signaling must be sent to a PCRF for which the PCA DSR has no connection, the message must be routed to a PCA DSR that does have a connection. This routing is configured using the DSR routing tables.

  See Diameter Routing and Communication with PCA for more details about Diameter routing for PCA .

Figure 3-7 Policy Client, PCRF, and Site Relationships