2 Diameter Message Encoding
Diameter Message Encoding
Introduction
The DCA client will send (and expect to receive) Diameter messages that have a basic encoding in compliance with RFC 6733.
Diameter Headers
The header of Diameter messages sent by DCA are fully compliant with RFC 6733.
The individual parameters are:
| Field | Type/Length | Comment |
|---|---|---|
| Version | 1 byte | Always set to 1. |
| Message Length | 3 bytes | Length includes header fields. |
| Command Flags | 1 byte |
Format: RPETrrrr All set as per RFC 6733. |
| Command Code | 3 bytes |
Will be one of:
|
| Application ID | 4 bytes | Set to 4 for CCRs, 0 for all other message types. |
| Hop-by-hop identifier | Unsigned32; 4 bytes | Set as per RFC 6733. |
| End-to-end identifier | Unsigned32; 4 bytes | Set as per RFC 6733. |
Attribute-Value Pairs (AVPs)
The header on an AVP consists of the following fields:
| Field | Type/Length | Comment |
|---|---|---|
| AVP Code | 4 bytes | |
| AVP Flags | 1 byte |
Format: VMPrrrrr: V is vendor bit. Will be set only if a vendor-ID is used. M is mandatory bit: If the AVP Code is from RFC 6733 or 4006, the bit is set. Otherwise (for example, a vendor specific AVP code), the bit is not set. P is an encryption indicator. Set to 0. |
| AVP Length | 3 bytes | AVP length in bytes, including these header fields. |
| Vendor-ID | 4 bytes | Will be 0 for RFC 6733 and 4006 AVPs, or 111 for Oracle specific AVPs. |
| Data | As specified by the AVP code and length. |
AVP Data Types
The DCA can send and receive all the basic and derived data types mentioned in RFC 6733, except Float32 and Float64. Where the data types are used, they are encoded in complete compliance with RFC 6733 and RFC 2279.
INAP extensions
The following may be mapped to or from INAP extensions:
- OctetString
- Integer32
- Integer64
- Unsigned32
- Unsigned64
- Address
- Time
- UTF8String
- DiameterIdentity
- DiameterURI
- Enumerated
Note: The OctetString type can have number values as an array of either ASCII characters or integers.
Extension formats
Supported INAP extension formats are:
- inapnumber
- asn1integer
- octets
- encoded (as ACS Profile Block)
INAP fields
As an alternative to extension formats, DCA also support mapping of AVPs to (Inbound) or from (Outbound) INAP Fields. Supported INAP Fields are:
| INAP Field | Direction |
| AdditionalCallingPartyID | Inbound only |
| CalledPartyBCDNumber | Inbound only |
| CalledParty | Inbound only |
| CallingParty | Inbound, Outbound |
| Cause | Outbound only |
| DestinationRoutingAddress | Outbound only |
| IMSI | Inbound only |
| LocationInformation | Inbound only |
| LocationNumber | Outbound only |
| MaxCallDuration | Outbound only |
| MscAddress | Inbound only |
| OriginalCalledParty | Inbound, Outbound |
| RedirectingPartyID | Inbound, Outbound |
Note:
Inbound direction (Diameter AVP to INAP Field)
Outbound direction (INAP Field to Diameter AVP)