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Request Routing Rules Overview

SBR Carrier maintains implicit and explicit routing rules for both authentication and authorization requests. When SBR Carrier receives a request, it examines the request to determine whether the type of request is authentication or authorization. Once the server determines the type of request, it consults the respective routing rules to determine how to route the request. The type of routing rules defined for authentication and authorization request are:

  • Implicit Routing Rules—Specifies the routing rules to be configured along with the function for some network element functions. For more information about the implicit routing rules and how to configure them, see Configuring Implicit Routing Rules.
  • Explicit Routing Rules—Provides greater flexibility for routing requests when implicit routing is not enough. For more information about the explicit routing rules and how to configure them, see Defining Explicit Routing Rules.

Authentication requests are applicable to the HSS function and the Downstream (server) function, whereas for authorization requests the only network element function associated is the Diameter downstream server function.

Routing Rule Evaluation and Rule Priorities

When a request is received, SBR Carrier identifies the request type and then evaluates the associated routing rules. First, the server evaluates any explicit routing rules defined for the request type. The order in which explicit routing rules are evaluated is user-defined. If no match is found, the server evaluates the implicit routing rules defined for the request type.

When a match is found, SBR Carrier processes the request by routing it to the specified destination. In some cases, this may mean simply forwarding the request to the destination. In other cases, for example if the HSS is listed as the destination, SBR Carrier check with the HSS for the subscriber credentials and then take the appropriate action.

If no routing rule match is found, SBR Carrier sends a response with an appropriate result code to the requestor.

Both the implicit and explicit routing rules can use the realm portion of the NAI decoration (username) to determine how to route requests. If the request does not contain an NAI, the Destination-Realm in the request is used. If the realm to which the request is to be routed is listed in the Self Names field, the realm is ignored and the request is treated as if it contained no realm. If no realm is present in either the NAI or the Destination-Realm, the request is considered to be local.

Note: For convenience, the Web GUI displays routing rules in the order in which they are evaluated.

Table 42 summarizes the priorities and routing rules for authentication requests. Authentication requests are applicable to the HSS function and the Downstream (server) function.

Table 42: Summary of Routing Rule Priorities for Authentication Requests

Priority

Rule

                  Functions

HSS

Downstream Diameter Server

1

Explicit

2

Implicit-IMSI Prefix

Not applicable

3

Implicit-Realm

4

Implicit-Default IMSI

Not applicable

5

Implicit-Default Realm

Table 43 summarizes the priorities and routing rules for authorization requests. Authorization requests are applicable only to the Downstream (server) function.

Table 43: Summary of Routing Rule Priorities for Authorization Requests

Priority

Rule

Downstream Diameter Server

1

Explicit

2

Implicit-Realm

3

Implicit-Default Realm

Modified: 2017-09-27