The DSR provides the following functions:
- Base Diameter Relay Agent: The DSR uses a Diameter Relay Agent to forward a message to the appropriate destination based on the information contained in the message.
- Core Routing and Load Balancing: The DSR creates a centralized Diameter signaling core that handles routing, traffic management and load balancing tasks, and provides a single interconnect point to other networks.
The IP Front End (IPFE) can run in a DSR system to distribute IPv4 and IPv6 connections from multiple clients to multiple Diameter Agent Message Processors (DA-MPs).
- DNS A and AAAA support: The DSR supports resolving host names using DNS A and AAAA queries based on the configured peer IP address of the connection when the peer IP address is not provisioned.
- Diameter Common Function: The DSR uses Diameter Common to configure the NOAM, SOAM and MP Profiles.
- The NOAM provide access to perform the following tasks:
Configure up to 2500 distinct combinations of Mobile Country Code (MCC) and Mobile Network Code (MNC).
Configure mapping of MCC+MNC combinations to Diameter Realms, MSIN prefix digits, and CC+NDC combinations.
- The NOAM provide access to perform the following tasks:
- Filter the list of MCC Ranges, to display only the desired MCC Ranges.
Sort the list entries in ascending or descending order by Start MCC values or End MCC values by clicking the column heading. By default, the list is sorted by Start MCC values in ascending ASCII order.
Add new MCC Ranges. If the maximum number of MCC Ranges (10) already exists in the system
- An MP Profile assignment for each DA-MP
- Diameter Transport Function:
Diameter can be distributed over multiple MPs; however, the Diameter Transport Function is responsible for managing the transport connections only on a single MP and relies on the Diameter Routing Function to perform distributed processing.
- Diameter connection management: Reporting of Diameter connection status changes,
The DSR supports up to 64 transport connections per Peer Node, and up to 32 Local Nodes.
The DSR supports multiple Diameter connections to any Peer Node and multiple Peer Nodes.
- Transport protocols: The DSR supports both Stream Control Transmission Protocol (SCTP uni-homing and multi-homing), Transmission Control Protocol (TCP), Datagram Transport Layer Security (DTLS)/SCTP and Transport Layer Security (TLS)/TCP based transport connections.
- Message Processing: Processing of Diameter Peer-to-Peer messages (CER/CEA, DWR/DWA, DPR/DPA), and delivery of Diameter Request and Answer messages from and to Diameter Peers and the Diameter Routing Function.
- Diameter Routing Function:
- Routing of Diameter Request and Answer messages to and from Diameter Peers (through the Diameter Transport Function) and DSR Applications.
- Peer Routing Rules: The DSR provides the ability to configure Peer Routing Rules that define where to route a Diameter message to an upstream Peer based upon Diameter message content.
- Processing of Diameter connection status from the Diameter Transport Function and status from DSR Applications for maintaining dynamic routing configuration data.
- Message Rerouting: A Diameter Relay Agent is responsible for making sure that Request messages are successfully delivered and to alternate route if failures are encountered.
- Alternate Implicit Routing: Instead of a message being routed directly to an available Peer Node, the message is routed on an “alternate implicit route” that is chosen from a list that has been configured for the Peer Node.
- Reroute on Answer: The DSR supports alternate routing of a Request message when an Answer response is received with a configured error code.
- Capacity and Congestion Status and Controls: Provides connection capacity status and controls, ingress message MPS controls, egress message throttling, and Egress Throttle Groups across DA-MPs.
- MAP-Diameter Interworking Functionallows the DSR to support the bi-directional interworking between Diameter and SS7 (GSM MAP) messages.
A Diameter-to-MAP transaction is a Diameter transaction that is initiated by a Diameter Node that is routed to a DSR for MAP-Diameter interworking. The operator is required to configure DRL ART rules which associate a Request message with the DM-IWF application.
A MAP-to-Diameter transaction is a MAP procedure that is initiated by a SS7 Node that is routed to a DSR SS7-MP for MAP-Diameter interworking.
- Diameter Mediation: The DSR provides configuration and application of rules that modify message processing behavior when conditions are met at specified points in the message processing.
- Message Copy: For a message that was routed through the DSR, the Diameter Message Copy feature provides the ability to forward a copy of the Diameter Request message, and optionally the Answer message, to a Diameter Application Server (a DAS Peer). Diameter Message Copy can be triggered by any processing functions acting on the messages, including Diameter Mediation, DSR Applications (such as the Charging Proxy Application - CPA), and Peer Routing Rules.
- Topology Hiding: Topology Hiding involves hiding and restoring topology-related information in messages.
- Diameter Topology Hiding can use Pseudo-Hostnames and encryption to hide topology-related information in messages sent from a Protected Network to an Untrusted Network, and to restore the topology-related information in messages from an Untrusted Network.
- The Policy and Charging Application (PCA) uses a configured list of Policy Client Peer Nodes from which the PCRF name is to be hidden.
- In the Charging Proxy Application (CPA), the Charging Proxy Function provides topology hiding using Virtual CDF and Virtual CTF Local Nodes. The CPF appears as a single CDF to the CTFs, and as a single CTF to the CDFs. The Charging Proxy Function modifies the Origin-Host and Origin-Realm AVPs in each message being routed to a CTF or CDF.
- The Application Chaining is a method for invoking multiple DSR Applications in sequence on the same DSR. With respect to DSR application chaining, an accessing region is a DSR network segment where the DSR has a direct connection to a policy client who initiates and sends a Diameter request directly to the DSR and a serving region is a DSR network segment where the PCA (either P-DRA or OC-DRA functionality) application actually receives and processes the Diameter request message as forwarded by DRL. Accessing region and serving region are all relative concepts, which make sense only relevant to a specific policy client and a specific DSR application (i.e. PCA). A serving region can be an accessing region as well for a policy client and PCA application, i.e. the DSR that receives a Diameter requests hosts the P-DRA that processes the Diameter requests.
- Integrated Diameter Intelligence Hub: The Integrated Diameter Intelligence Hub (DIH) provides the ability to troubleshoot Diameter transactions.
- DSR Switchover: The DSR servers operate in redundancy mode and support automatic failover to the standby server if the active server fails. Automatic failover does not require manual intervention.
- IPsec Support: The DSR supports transporting messages over Internet Protocol security (IPsec) secure connections.
- IPv4 and IPv6 Support: The DSR supports IPv6 and IPv4 IP address formats.