Page 414 - 5G Basics - Core Network Aspects

1 Core network aspects

different requirements of various kinds of services. A charging system is recommended to support various
charging resources, including service types, service launched time, service end time, session duration, calling party
ID, called party ID, session media type, subscriber type (such as a monthly or pay-as-you-go subscriber), etc.
The charging mechanisms of eMMTel can be divided into different categories. According to charging modes,
it includes online charging and offline charging. According to charging policies, it includes flow charging,
monthly rental charging, using frequency charging, etc. eMMTel is recommended to simultaneously support
more than one charging mechanism for different services.

The eMMTel service user can be charged according to the different service combinations and their
characteristics.. IM chat, file transfer and content sharing services can also be charged based on application
server-generated charging data record (CDR) according to the flow and usage frequency. The specific
charging requirements can be defined according to the strategy of the operator.

11 Security and privacy considerations

11.1 Access security for the user-to-network interface (UNI)
Network access authorization and authentication are prerequisites to protect network security. In multi-
connection, multi-connection network providers are required to restrict access to authorized subscribers,
and prevent unauthorized access, such as by intruders masquerading as authorized users. It is required to
support capabilities for authenticating subscribers, equipment, network elements and other providers.

The access security should provide capabilities to ensure that users are prevented from gaining information
or resources that they are not authorized to access. The UNI access control provides the means of ensuring
that users access resources only in an authorized manner. Resources concerned may be the subscribed
services and network address book provided by eMMTEL.

11.2 Security for the service
Service security of eMMTel includes all the related problems in a legacy network. Authentication,
authorization and access control are required to be supported. Before a service is provided, both terminal
device and subscriber should be authenticated in a secure manner. And the subscriber should be authorized
while accessing specific services and contents. Service access control should include encryption and
decryption functions for service signalling and content flow, which can mutually prevent unwanted or
unauthorized access for service provider and subscriber.
In order to improve the quality of service and for convenience, the behaviour of all the users should be
authorized and controlled. Besides keeping service availability to a maximum, the application domain should
ensure the eMMTel application server is safe, thus avoiding packet attack, intrusion and virus exposure from
the Internet. The service and user information should be protected from attack stealing, session hijacking
attack and unconscious leaking.
Several access security and authentication methods of control signalling should be specified for accessing the
application domain and eMMTel service. The applicability and choice of method is highly dependent on the
eMMTel client and access type (e.g., trusted or untrusted) including what is supported or required by the
network.

In the eMMTel environment, eMMTel devices can access the network by multiple (both mobile and
broadband/fixed networks) interfaces, so the separated access signalling security method and corresponding
authentication are required.
Access media security is very important in the eMMTel environment. Secure RTP (SRTP) may be used to
provide message authentication, integrity protection and encryption for both RTP and RTCP streams involved
in real-time video and voice sessions. It is recommended that communication confidentiality over any
operational untrusted access network be managed in a secure manner. MSRP is used in the services that
include the exchange of images, files and instant messages. MSRP is the same as RTP in establishing sessions
through SDP exchanges in SIP signalling. And it heavily relies on the security provided in signalling. So the
signalling security protection is also suitable for it.

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