Mobile network traffic is growing exponentially, and service providers must manage their networks efficiently to meet consumer demand. The technology evolution of radio access networks is limited by the laws of physics, and significant growth in radio frequency (RF) efficiency can no longer be expected. Long-Term Evolution (LTE) radio access is reaching the limits of Shannon's law, the spectrum available for mobile data applications is limited, and the only solution for increasing overall mobile network capacity is to increase the carrier-to-interference ratio while decreasing cell size and deploying small cell technologies.
In this context we will discuss about the latest AAA protocol being deployed by SP's Worldwide for managing mobile traffic in both licensed and unlicensed spectrums .
DIAMETER is a new framework in the Internet Engineering Task Force (IETF) for the next-generation AAA server.
And the Message structure is of following sort. .
Lets quickly go through few major difference betweens RADIUS and DIAMETER in a nutshell .
|Communications Ports||1812- UDP ,1813- Accounting||3686 for base protocol|
|Error reporting scheme||Not supported||Supported|
|Transport method||UDP||SCTP or TCP and optionally also use UDP|
|Maximum size of attributes||255 Bytes||16MB|
|Reliability||Not reliable||Acknowledgement for packets ,|
Discarding of packets .
Packets that do not contain the expected information,or that have errors, are silently discarded.
Server can notify the client of problem by sending an error message
In this section we will discuss some the benefits of DIAMETER based on various characteristics required in AAA operations .
RADIUS does not have any kind of failover mechanism, even it can't have failover mechanism because it is UDP based .DIAMETER defines the Application layer acknowledgements and failover methods which we will define later.
|Transmission Layer Security|
RADIUS does not provide per packet confidentiality. RFC-3162 provide IPsec but it is not mandatory, while in diameter it is mandatory to apply per packet confidentiality with the help of IPSec (IP Security) and TLS (Transport Layer Security).
Capability negotiation .
Peer discovery and Configuration
Authentication replay attack prevention through encryption
Diameter AVPs are the basic unit inside the Diameter message that carries the Data(Authentication Data , Security Data , Data pertaining to Application etc). There must be at least one AVP inside Diameter message.
The AVP Code, combined with the Vendor-Id field, identifies the attribute uniquely. AVP numbers 1 through 255 are reserved for backward compatibility with RADIUS, without setting the Vendor-Id field. AVP numbers 256 and above are used for Diameter, which are allocated by IANA .