Diameter is an authentication, authorization, and accounting protocol for computer networks. The Diameter base protocol is defined by RFC ( Obsoletes: RFC ) and CCR, , Diameter Credit-Control Application – RFC Diameter Credit-Control Application, is a networking protocol for Diameter application used to implement real-time credit-control for a variety of end user services. It is an IETF standard defined in RFC RFC (part 1 of 5): Diameter Credit-Control Application. Network Working Group H. Hakala Request for Comments: L. Mattila Category: Standards.
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Diameter is an authentication, authorization, and accounting protocol for computer networks. It belongs to the application layer protocols in the internet protocol suite.
RFC – part 1 of 5
The name is a play on words, derived from the RADIUS protocol, which is the predecessor a diameter is twice the radius. Diameter is used for many different interfaces defined by the 3GPP standards, with each interface typically defining new commands and attributes. Adding a new optional AVP does not require a new application. The Diameter protocol was initially developed by Pat R. The Diameter protocol defines a policy protocol used by clients to perform policy, AAA, and resource control.
This allows a single server to handle policies for many services. Diameter Applications can extend the base protocol by adding new commands, attributes, or both. The packet consists of a Diameter header and a variable number of Attribute-Value Pairs, or AVPs, for encapsulating information relevant to the Diameter message. This field diameher the version of the Diameter Base Protocol. As ofthe only value 40066 is 1.
Diameter Credit-Control Application
The Message Length field indicates the length of the Diameter message in bytes, including the header fields and the padded AVPs. The ” R ” Djameter bit — If set, the message is a request. If cleared, the message is an answer. If cleared, the message MUST be locally processed. The ” E ” Error bit — If set, the message contains a protocol error, and the message will not conform to the CCF described for this command. Messages with the “E” bit set are commonly referred to as error messages.
The ” T ” Potentially re-transmitted message bit — This flag is set after a link failover procedure, to aid the removal of duplicate requests. It is set when resending requests not yet acknowledged as an indication of a possible duplicate due to a link failure.
The values are for permanent, standard commands allocated by IANA. A Command Code is used to determine the action that is to be taken for a particular message.
Some common Diameter commands defined in the protocol base and applications are:.
Information on RFC » RFC Editor
Application-ID is used to identify for which Diameter application the message is applicable. The application can be an authentication application, an accounting application, or a vendor-specific application. The Hop-by-Hop Identifier is an unsigned bit integer field in network byte order that is used to match the requests with their answers as the same value in the request is used in the response.
The Diameter protocol requires that relaying and proxying agents maintain transaction state, which is used diametee failover purposes. Transaction state implies that upon forwarding a request, its Hop-by-Hop Identifier is saved; the field is replaced with a locally unique identifier, which is restored to its original value when the corresponding answer is received.
Received answers that do not match a known Hop-by-Hop Identifier are ignored by the Diameter agent. In case of redirecting agents, the Hop-by-Hop Identifier is maintained in the header as the Diameter agent responds with an answer message. The End-to-End Identifier is an unsigned bit integer field in network byte order that is used to detect duplicate messages along with diamrter combination of the Origin-Host AVP. When creating a request, the End-to-End Identifier is set to a locally unique value.
The End-to-End Identifier is not modified by Diameter agents of any kind, and the same value in the corresponding request is used in the answer. When set the AVP Code belongs to the specific vendor code address space.
If an AVP with the ” M ” bit set is received by a Diameter client, server, proxy, or translation agent and either the AVP or its value is unrecognized, the message must be rejected. Diameter Relay and redirect agents must not reject messages with unrecognized AVPs. The RFC defines a core state machine for maintaining connections between peers and processing messages.
Diametter is part of the basic protocol functionality and all stacks should support it and as such abstract from the connectivity related operations. Additionally, application specific state machines can be introduced either later or at a higher abstraction layer.
The RFC defines an authorization and diameyer accounting state machine. After that the transport connection can be disconnected. Obsolete RFCs are indicated with strikethrough text. From Wikipedia, the free encyclopedia. This section needs expansion. You can help by adding to it. Retrieved 30 April Archived from the original on 4 July Retrieved 12 October Retrieved from ” https: Internet Standards Application layer protocols Computer access control protocols Authentication protocols.