Software Overview

Overview

The Ribbon DSC is a product that is designed for Diameter protocol-based signaling in a carrier IP network. This signaling comprises control and monitoring of the given IP network, efficient routing of messages, and feasible use of network resources. The Ribbon DSC provides high throughput IP traffic processing.

This section presents you with unique Ribbon DSC elements and concepts that you should be familiar with to fully understand how to configure and use this product.

Ribbon Signaling Systems

The Ribbon DSC is implemented on the DSC Platform and is equipped with Routing and Management VMs and Routing VMs licensed for the Ribbon DSC application.

For more information about the DSC Platform, refer to the Installation Guides.

Ribbon DSC on the DSC Platform (Example)

Ribbon DSC

The  Ribbon DSC (see the following figure) is deployed over multiple VMs licensed for Ribbon DSC applications as a DSC Instance (see the following section, DSC Instance).

Top-level Ribbon DSC Elements

DSC Instance

The representation of a Ribbon DSC in the Web UI is a DSC Instance. The DSC Instance is implemented through a distributed process across VMs licensed for Ribbon DSC applications. For every VM  (Management/Routing VM and Routing VM), there are up to 10 DSC instances.

DSC Node

A DSC Node is a logical entity in a Diameter network. This node type has a unique Diameter ID (for example, dsc.sonusnet.com). The node may also be identified by its internal name.

DSC Nodes contain Adjacent Diameter Nodes (ADNs) and Transport Servers to enable connectivity using SCTP and/or TCP on each virtual slot (typically, on each VM licensed for Ribbon DSC applications).

Each DSC Node is independent of the other nodes in that different DSC Nodes do not exchange messages. If Diameter messages have to be routed between two DSC Nodes, these nodes must be provisioned as Adjacent Diameter Nodes (ADNs) and routing tables must be provisioned appropriately as if the DSC Nodes were external Diameter Nodes.

The DSC supports up to 32 DSC Nodes per DSC Instance.

For more information DSC Nodes, refer to Configuring DSC Nodes.

DSC Definitions

Use the DSC Definitions to define basic Diameter message elements (see the following figure).

For more information about DSC Definitions, refer to Configuring Ribbon DSC Definitions.

DSC Definitions

DSC Parameter Sets

DSC Parameter sets exist with default values (see the following figure). You should only create a new DSC Parameter Set if these values are insufficient for your given connection. Do not reconfigure the default parameter sets with new values. If required, create a new DSC Parameter Set and configure it as required.

For more information about DSC Parameter Sets, see Configuring DSC Parameter Sets.

DSC Parameter Sets

Server Pools

The DSC Node can define Server Pools to indicate which servers should be considered for a particular Application ID. Load Balancing can be set based on Round-Robin or Least Loaded. Session Binding is also available.

For more information about Server Pools, see Configuring Server Pools.

Transport Servers

A DSC Node connects to other DSC Nodes in a Diameter network by defining ADNs (see the following section, Adjacent Diameter Nodes (ADN) and Connections) and Transport Servers.

Transport Servers are necessary if the ADN Connection from the remote node is a client only.

The Transport Server contains a DSC Slot attribute that identifies the VM which manages this Transport Server. Only the DSC Process that manages the Transport Server opens the corresponding network service.

For more information about Transport Servers, see Configuring Transport Servers.

Adjacent Diameter Nodes (ADN) and Connections

An Adjacent Diameter Node (ADN) is any node on the Ribbon DSC or in the Diameter network (see the following figure).

Adjacent Diameter Nodes Connectivity (Example)

As shown in the preceding illustration, the Home Subscriber Server (HSS) and the DEA on the other network are Adjacent Diameter Nodes (ADNs).  3 GPP refers to these as Diameter Peers, however, the term “Peer” is used within our redundancy libraries for other entities, therefore, we use the term “ADNs”.

Usually, connections are made to the external DSC Node from at least two VMs licensed for the Ribbon DSC application. Each DSC Node has its own Diameter ID.  The DSC Node also has a unique IP address/port for each VM that is running the Ribbon DSC application.

For more information about ADNs, see Configuring Adjacent Diameter Nodes.

The ADNs communicate through the Diameter protocol and the connections can be as follows:

Diameter ADN Connections

Diameter ADNs represent connections to other Diameter entities (nodes) in the Diameter network.

Diameter User Application (UA)  and XML ADN Connections

User Applications (UAs) may connect to a DSC Node using TCP or SCTP and are able to send and receive Diameter messages. A UA may originate, terminate, relay, redirect or proxy Diameter messages. Some UAs may communicate using XML messages rather than using Diameter messages; such an application is an XML UA. This UA is represented in the Web UI as an Adjacent Diameter Node of type UA XML. However, other than the message format and some minor configuration differences, an XML UA and a UA have the same function. For this reason, through the rest of this document, a UA should be understood to mean either a Diameter UA or XML UA unless otherwise stated.

DSC Internal ADN Connections

DSC Internal ADNs represent internal connections between DSC Processes (see DSC Processes and Process Dependencies) within the same DSC Node.

DSC DB ADN Connections

DSC DB ADNs represent internal connections between DSC Processes and IP Connectivity Access Network (IP-CAN) Session DBs.

For more information about ADN Connections, see Configuring ADN Connections.

DSC Routing Tables

The Ribbon DSC Routing Tables are a data-driven method of filtering, routing, and, if required, modifying Diameter messages. In the case of default routing (see Default Routing of Diameter Signaling Traffic), the routing tables do not have to be used for configuration. These tables, however, are used in special routing scenarios (see  Routing of Diameter Signaling Traffic using Routing Tables).

For more information about Routing Tables, see Configuring Ribbon DSC Routing Tables.

Routing Tables

References

For additional terminology used by the Diameter protocol, refer to RFC 6733 Diameter Base Protocol.