NPN For Dummies: PART V
Index of contents:
NPN core’s main function is to make decisions about who is allowed to connect to the network and access which of its services
In a public mobile network the core’s most important functions, as uninspiring as this may sound, is billing or charging. In Telecom parlance this happens at the intersection of two critical core pillars, the OSS (Operational Support Systems) and BSS (Business Support Systems). Some years ago this somewhat deflatingly reductionist view of the mobile carrier came to the mouths of many C-level executive stating that billing was the core competence of the telecom carrier. Not at all required for the Non-public Network, this is of course their primary difference. Now, think about all that network gray matter suddenly freed up to do other, much more interesting things.
The NPN core’s main function is to make decisions about who is allowed to connect to the network and access which of its services. This is the all important IT arenas of “authentication” and “authorization”. Where single and multi-factor authentication in the traditional IT network is handled by user input (passwords, biometrics etc.), in the NPN it is based on SIM cards. SIM cards can be either physical or virtual, eSIMs. SIM cards can be issued by different parties and they have many different security parameters in order to ensure that their connection over the air is secured and cannot be compromised. Authentication can be done by the NPN itself or the NPN can be connected to another network most often public networks, leaving the sometimes tricky requirement of authentication to them. Additionally, the Core can also authenticate WiFi devices as well as satellite-based communication devices. This is an additional functionality called N3IWF or Non 3GPP Inter Working Function.
The Handshake
Following successful authentication of a given user device, the Core proceeds to assign the actual data connection, known in the lingo as a PDU (Protocol Data Unit) session. This handshake includes the policies associated with that end device, most typically called the UE (User Equipment). Specifically, these policies define the performance and range that UE will be granted, its capacity, latency and locations in the cellular network or networks where it can be served. Remember that a network, like the brain or a national economy, has a certain, limited amount of resources that need to be allocated thoughtfully in order to support users and effectively manage congestion. Simply put, the “policy” thus defines the UE’s priority when resources become more scarce.
Harking back to our earlier chapter tuned into the radio side of the network, you may recall that a basestation maintains a maximum number of simultaneous users and associated data sessions or PDUs. In addition to defining performance, these UE-specific policies can also define thresholds by which the UE can be removed in the case of congestion. These UE profile defined policies or rules fall into the domain known as Quality of Service (QoS). An umbrella term, QoS covers many different topics. At times feeling like a euphemism, akin to the network carrier’s QoS disclaimer known as “Best Effort”, when your phone isn’t quite cutting it on the data side that is a quite deliberate result of your QoS profile.
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NPN FOR DUMMIES
To provide IT Infrastructure and management professionals a well-grounded understanding of the what, why, how and how much of owning and operating their own NPN, to inform and support their development and delivery of an effective business case for such a project to their organization.
