References:
The following documents describe Diameter Configuration components, provide configuration procedures, and list the sequence in which to perform the configuration of the components.
Users' Guides for DSR Applications indicate Diameter Configuration components that require specific configuration for the application.
Diameter Routing Function Configuration
The DSR requires configuration for Diameter routing functions and Diameter transport connection management functions.
Message routing is provided through the DSR. The DSR functions as a Diameter Relay Agent to forward messages to the appropriate destination based on information contained within the message, including header information and applicable Attribute-Value Pairs (
AVP). User-defined Peer Routing Rules define where to route a message to upstream Peer Nodes. Application Routing Rules route messages to DSR Applications. The DSR provides the capability to route Diameter messages based on any combination of, or presence or absence of, the following message parameters:
- Destination-Realm
- Destination Host
- Application ID
- Command Code
- Origination Realm
- Origination Host
- IMSI
The DSR supports multiple transport connections to each Peer Node and provides the following functions:
- Routing Diameter Request and Answer messages received from Diameter Peers
- Weighted load sharing
- Priority routing
- Rerouting
- Message Copy to a DAS
Configuring Diameter routing can include:
- Creating Route Groups and assigning Capacity levels to each Peer Node in each Route Group
- Creating Route Lists and defining Active and Standby Route Groups in each Route List. Active and Standby status is determined by Peer Node Priority and Weight
- Creating Peer Routing Rules and assigning Route Lists and Priorities to the rules
- Creating Application Routing Rules that route messages to DSR Applications
- Configuring Trusted Network Lists, Protected Networks, and Configuration Sets for Diameter Topology Hiding functions
- Creating Message Copy Configuration Sets for Diameter Message Copy functions
- Creating Egress Throttle Groups to manage egress message throttling from a DSR to a Peer Node on a specified set of Connections. The Egress Message Rate, Egress Pending Transactions, or both, can be throttled.
Diameter Transport Function Configuration
The Diameter Transport Function communicates connection management information to the Diameter Routing Function that it needs for making routing decisions (including Operational Status changes, rerouting Requests, and Connection Priority Level changes).
A transport connection provides the reliable transport connectivity between a Local Diameter Node and a Peer Diameter Node. A transport connection must be configured in order for the Diameter Routing Function to allow a transport connection to be established with a Peer Diameter Node. A transport connection may use the SCTP or TCP transport protocol. A node using the SCTP transport protocol can be configured to advertise more than one IP address and to establish SCTP paths to more than one Peer IP address. Two IP Addresses are supported for an SCTP multi-homed connection both for the Local Node and Peer Node.
The Diameter Transport Function and the Diameter Routing Function can exchange Diameter messages between instances that are on either the same or different DA-MPs within the DSR NE. Ingress Request messages accepted by the Diameter Transport Function will always be sent to the local Diameter Routing Function instance for routing. The local Diameter Routing Function instance will route the Request. The Diameter Routing Function can choose an egress connection that is owned either by the local Diameter Transport Function instance or by another (remote) Diameter Transport Function instance.
The primary transport Diameter configuration components are Local Nodes, Peer Nodes, Connections, and Configuration Sets. The DSR supports both IPv4 and IPv6 connections.
Configuration for transport includes:
- Connection TCP or SCTP transport protocol, SCTP multi-homing or uni-homing, and Fixed or Floating (IPFE TSA) connection type
There are two types of Transport Connections:
- A Fixed connection can be assigned to one and only one DA-MP at configuration time.
- An IPFE floating connection is implicitly assigned to a set of DA-MPs through the IPFE Target Set Address (TSA) assigned to the connection. The location of the connection is unknown until the connection is established on one of the DA-MP location candidates. See IP Front End (IPFE).
- Local Node FQDN, Realm, IP Addresses, and transport protocol
- Peer Node FQDN, Realm, IP Addresses, and transport protocol
- Connection, Capability Exchange (CEX), and Message Priority Configuration Sets
A Connection Configuration Set provides transport protocol and Diameter "tuning" for a transport connection to account for the network QoS and Peer Node requirements, and settings for Peer-initiated connections to a Local Node.
Diameter Peers must perform Capabilities Exchange in order to discover the Peer's identity and capabilities. Capabilities Exchange validation of a Peer's identity and capabilities includes processing and validation of the following AVPs:
- Origin-Host
- Origin-Realm
- Auth-Application-ID(s)
- Acct-Application-ID(s)
- Vendor-Specific-Application-ID(s)
- Host-IP-Address(es)
A user defined Message Priority Configuration Set contains a Message Priority that can be assigned to an ingress Diameter message, for use in algorithms for preferential discard, throttling, and routing by Peer Nodes and Local Nodes.
- Common Application IDs
- Capacity (ingress and egress message rates) and Congestion Controls:
- The DA-MP Overload Control (Message Priority and Color-Based DA-MP Overload Control) provides a mechanism for managing internal/local DA-MP congestion detection and control. The DA-MP Overload Control feature tracks ingress message rate, calculates the amount of traffic that needs to be shed based on CPU congestion, and sheds that traffic based on Message Priority, Message Color, and discard policy.
- The User Configurable Message Priority feature provides Message Priority that can be assigned to ingress Diameter messages, based on certain configurable criteria, for use in algorithms for preferential discard, throttling, and routing by Peer Nodes and Local Nodes. Message Priority Configuration Sets are assigned to Peer Nodes and Connections to provide the Message Priority during ingress message processing.
- The Per Connection Ingress MPS Control (PCIMC) feature limits to a configurable level the per-Connection ingress message rate of each connection. Correctly configured message rate controls ensure that a single Connection cannot use the majority of the resources. (No limiting is done by PCIMC for the egress message rate.)
- The Remote BUSY Congestion feature addresses Remote Congestion detection. The DSR Remote BUSY allows DSR egress Request routing to select a BUSY Connection (that is abating its BUSY status) based on the User Configurable Message Priority assigned to the message.
- The Egress Transport Congestion feature uses Congestion Levels to manage the egress message traffic flow on a Diameter Peer Connection when the Connection's TCP/SCTP send buffer is exhausted, as indicated by the TCP/SCTP socket being "blocked".
- The Per Connection Egress Message Throttling feature targets congestion avoidance by throttling the volume of Diameter traffic being sent over a Connection when the traffic exceeds the configured maximum egress message rate of the Connection.
- The User-Configurable Connection Pending Transaction Limiting feature provides the ability to configure the Connection Pending Transaction Limit for each DSR Peer Connection.