Roaming is a concept used in Network Configuration and Change Management, it is related to the ability of a device to move from one coverage area to another. The concept of roaming used in Wi-Fi means that the Wi-Fi client can register on different bases or access points while on the move.
In mobile telephony, roaming is the ability to send and receive calls on mobile networks outside the local service area of the company, ie, within the service area of another company in the same country, or during a stay in another country, using the network of a foreign company.
The roaming service has made it possible for mobile users to gain complete freedom of movement between the coverage areas of different telecommunications companies.
It allows a user who is within the coverage area of a mobile network other than the one that provides the service to receive calls made to your mobile number without making any extra procedures and, in many cases also make calls to the home network without having to make a special dial.
To achieve this, both companies (the original network service provider and the owner of the network in which the customer is roaming) must have signed a roaming agreement, which define which clients have access to the service and how the connections between their systems to route calls works.
While the service allows instant communication and, in many cases, without the need for any additional requests, it is noteworthy that usually the cost of each call transfer and interconnection costs are charged to the receiver of the call, not the person who called.
Roaming Wi-Fi networks
To make it possible, there must be a small overlap (overlapping) in the coverage of APs (access points), so that users can navigate through and always have coverage. The access points incorporate an algorithm that decides when a station should disconnect from an access point and when connected to another. This is very common in different campus faculties having different access points. Walking among them disconnects from one to another.
Voice over IP (VoIP) is a technology that allows you to communicate by voice (or via RSS multimedia: audio or video) on compatible IP networks, whether private networks or the Internet, wired or not (satellite, WiFi, GSM, UMTS or LTE). This technology is mainly used to support the service of voice over IP (VoIP)
The transmission of voice over IP is relatively complex. The first step is the digitization of the acoustic signal. This is the coding. Then, the information is divided into frames that can run on a Network Configuration and Change Management .