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5G Network Interview Questions
Following are the functions performed by RRC layer in 5G NR protocol stack.

* Broadcast SI (System Information) messages to AS (Access Stratum) and NAS (Non-Access Stratum).
* Handles paging initiated by 5GC (5G Core Network) or NG-RAN (Radio Access Network).
* Establishment, maintenance and release of RRC Connection between 5G NR UE and NG-RAN. This includes addition, modification and release of CA(carrier aggregation) and Dual connectivity in NR or between E-UTRA and NR.
* Security related functions including key management
* Establishment, configuration, maintenance and release of SRBs (Signaling Radio Bearers) and DRBs (Data Radio Bearers).
* Mobility functions such as handover, context transfer, UE cell selection/re-selection, control of cell selection/re-selection, Inter-RAT mobility etc.
* QoS management
* UE measurement reporting, control of reporting
* Detection of radio link failure and recovery from radio link failure
* NAS message transfer to/from NAS from/to UE
Not physically. If, for example, a service provider has a 4G cell and wants to add 5G radios to that macro towers, they would likely end up sharing the aggregation and core network back to the data center, perhaps over different wavelengths or different parts of the network, L2/L3 VPNs, or Optical VPNs. Rolling out completely separate networks for both it would become cost prohibitive quickly and much harder to get to ROI. Some parts of the network will be only for 5G, and some shared.
It depends on what you classify as a “thing”. If it includes HD surveillance camera, for example, that runs on a cellular network, then yes, and lots of it. Smaller things, such as temperature sensors, will generate far less traffic, but there may be billions of them deployed, so it adds up quickly. For the most part, the challenge of Internet Of Things (IoT) will likely be about the number of individual services, not capacity.
IPv6 will have a big place in 5G, primarily because of the Internet of Things (IoT), which will add tens of billions of new devices to this mobile network as it’s roll out. IPv4 cannot cope with the number of unique IP addresses that will be required, but IPv6 can.

IPv6 also introduces the Neighbor Discovery Protocol (NDP) that enables multiprotocol interoperability between IoT devices. So, both the number of addressable addresses in IPv6 and the features of the protocol will be critical to the success of 5G.
Many of the big carriers are working on building up their 5G networks now. This includes Verizon, AT&T and Sprint. Verizon is working on implementing mmWave, and T-Mobile is working on low- and midband 5G first.
 
Led by T-Mobile, carriers are starting to embrace the idea of a multi-tier 5G strategy, which includes the use of low-band, midband and mmWave frequencies. T-Mobile has started to launch 5G in half a dozen markets currently.
 
Verizon is another leader in the 5G market and is currently focusing on the implementation of mmWave 5G. In addition, Verizon created an investment fund named Verizon Ventures. Verizon Ventures aims to invest in areas that would benefit from 5G, such as augmented reality, IoT and artificial intelligence.
 
Sprint is also offering midband 5G using 2.5 GHz frequencies. AT&T has started investing in 5G but is currently lagging behind the competition a bit. The company has also rolled out 5G Evolution (5GE), which is not actually 5G.
AT&T has released a 5GE network, and in an update, 4G LTE users have gotten an "upgrade" to 5GE. However, 5GE is just a rebranding of AT&T's Gb 4G LTE network. AT&T argues that the speeds are close enough to 5G, but it is technically not 5G. The G stands for generation, typically signaling a compatibility break with former hardware. 5GE does not follow this trend and is technically not 5G. This marketing strategy may mislead individuals who do not know 5GE is not actually 5G.
Private 5G networks are nonpublic mobile networks that can use licensed, unlicensed, or shared spectrum. Private 5G networks are meant to augment existing capabilities and introduce new possibilities that other systems are not able to support.
There are multiple models for how a private 5G network can be architected, deployed, and operated, including:
 
* Wholly owned and operated private 5G networks, where an organization owns all the equipment, private clouds, and spectrum, and manages the network in-house

* Hybrid private-public cloud 5G networks, where a business may own or lease on-premises equipment and use a public or private cloud service to host parts of the network

* Private 5G delivered via network slicing, which may include an on-site Radio Access Network (RAN) and other equipment, depending on application needs

* Neutral host networks with a RAN and signal sharing
While both private 5G and Wi-Fi can work together and make network services such as internet access available wirelessly, they have some key differences.
 
It's important to note that 5G isn't intended to replace Wi-Fi. Each technology has unique advantages depending on settings and use cases.
 
Wi-Fi is a familiar standard, and one that millions of endpoints in organizations worldwide can use daily. Wi-Fi infrastructure is relatively inexpensive to install and manage. However, Wi-Fi has limitations in its usefulness as a standalone solution for connectivity:
 
Security : Threats such as malware may only need to steal or spoof credentials to gain access to networks. Private 5G communications are encrypted, and an appropriate SIM card must be present in the endpoint device to enable access.
 
Coverage : Wi-Fi deployments can be complex and cost-prohibitive in large usage areas such as airports or event venues, given the high number of endpoints needed. In remote areas where comprehensive Wi-Fi infrastructure does not exist, 5G and 4G can offer greater coverage without wiring.
 
Performance :
Both Wi-Fi and 5G operate on shared spectrums. Wi-Fi can experience performance challenges in terms of how it shares bandwidth across connected devices; in addition, Wi-Fi is more prone to interference and usage-based fluctuations. The number of access point handoffs can cause lags and dropouts.
 
In theory, Wi-Fi is capable of 5G's performance. In reality, Wi-Fi isn't able to offer the same reliability and performance guarantees that 5G can provide, such as low latency, faster speed, and greater bandwidth.
 
The best way to compare private 5G and Wi-Fi is to see how they will both have a role to play in supporting enterprises and organizations in the future. Most of today's computing devices work very well on Wi-Fi connections, although the same devices—if equipped for 5G—can often operate many times faster via 5G connection.
Private 5G network ranges can cover anywhere from a few thousand square feet to dozens of square kilometers, depending on the power of the radio transmitter, the band being used, and the needs of the user.
 
A typical 5G radio operating on low, mid, and high bands offers the following ranges :
 
Low-band :
* Less than 1 GHz
* Hundreds of square miles
* Speeds of less than 300 Mbps
 
Mid-band : 
* Sub-6 GHz
* Several-mile radius
* Can reach low Multigigabit speeds
 
High-band or mmWave : 
* Less than 1-mile radius today
* Mid to high Multigigabit speeds

Sources : qualcomm, cisco, verizon, techtarget, more..