Location Information Server
Encyclopedia
The Location Information Server, or LIS is a network node
originally defined in the National Emergency Number Association
i2 network architecture
that addresses the intermediate solution for providing e911 service for users of VoIP telephony. The LIS is the node
that determines the location of the VoIP terminal
.
Beyond the NENA
architecture and VoIP, the LIS is capable of providing location information to any IP
device within its served access network
.
or DSL a wiremap method is common. In wiremap location determination, the location of a device is determined by finding which cables are used to send packets to the device. This involves tracing data through aggregation points in the network (such as Ethernet
switches, or DSL access nodes) and finding the port that packets for that device are sent to. This information is combined with data available to the LIS (usually extracted from a database
) to determine a final location. How this tracing is done then depends on the type of network.
In wireless networks, a range of technologies can be applied to location determination, the most basic of which uses the location of the radio transmitter as an approximation. The actual method applied is similar to the wiremap method, if a radio transmitter can be identified, then the location of the device can be given as the position of the transmitter with a region of uncertainty
.
has defined an architecture and protocols for acquiring location information from a LIS. A LIS in the immediate access network is automatically discovered and location information is retrieved using the HELD protocol. Location information can be retrieved directly—known as by value—or the LIS can generate a temporary URI
that can be used to provide location indirectly—known as a location URI.
The location information provided by a LIS primarily uses the GEOPRIV format (RFC 4119), an XML
representation based on the presence
format defined in RFC 3863. RFC 4119 provides a container for both geodetic position and civic address information (now updated by RFC 5139) and also defines elements for expressing a user's privacy preferences.
Node (networking)
In communication networks, a node is a connection point, either a redistribution point or a communication endpoint . The definition of a node depends on the network and protocol layer referred to...
originally defined in the National Emergency Number Association
National Emergency Number Association
The National Emergency Number Association is an organization whose mission it is to foster the technological advancement, availability, and implementation of a universal emergency telephone number system in the United States. In carrying out its mission, NENA promotes research, planning, training...
i2 network architecture
Network architecture
Network architecture is the design of a communications network. It is a framework for the specification of a network's physical components and their functional organization and configuration, its operational principles and procedures, as well as data formats used in its operation.In...
that addresses the intermediate solution for providing e911 service for users of VoIP telephony. The LIS is the node
Node (networking)
In communication networks, a node is a connection point, either a redistribution point or a communication endpoint . The definition of a node depends on the network and protocol layer referred to...
that determines the location of the VoIP terminal
Terminal (telecommunication)
In the context of telecommunications, a terminal is a device which is capable of communicating over a line. Examples of terminals are telephones, fax machines, and network devices - printers and workstations....
.
Beyond the NENA
National Emergency Number Association
The National Emergency Number Association is an organization whose mission it is to foster the technological advancement, availability, and implementation of a universal emergency telephone number system in the United States. In carrying out its mission, NENA promotes research, planning, training...
architecture and VoIP, the LIS is capable of providing location information to any IP
Internet Protocol
The Internet Protocol is the principal communications protocol used for relaying datagrams across an internetwork using the Internet Protocol Suite...
device within its served access network
Access network
An access network is that part of a telecommunications network which connects subscribers to their immediate service provider. It is contrasted with the core network, which connects local providers to each other...
.
The Role of the LIS
Distributed systems for locating people and equipment will be at the heart of tomorrow's active offices. Computer and communications systems continue to proliferate in the office and home. Systems are varied and complex, involving wireless networks and mobile computers. However, systems are underused because the choices of control mechanisms and application interfaces are too diverse. It is therefore pertinent to consider which mechanisms might allow the user to manipulate systems in simple and ubiquitous ways, and how computers can be made more aware of the facilities in their surroundings. Knowledge of the location of people and equipment within an organization is such a mechanism. Annotating a resource database with location information allows location-based heuristics for control and interaction to be constructed. This approach is particularly attractive because location techniques can be devised that are physically unobtrusive and do not rely on explicit user action. The article describes the technology of a system for locating people and equipment, and the design of a distributed system service supporting access to that information. The application interfaces made possible by or that benefit from this facility are presentedLocation Determination
The method used to determine the location of a device in an access network varies between the different types of networks. For a wired network, such as EthernetEthernet
Ethernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....
or DSL a wiremap method is common. In wiremap location determination, the location of a device is determined by finding which cables are used to send packets to the device. This involves tracing data through aggregation points in the network (such as Ethernet
Ethernet
Ethernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....
switches, or DSL access nodes) and finding the port that packets for that device are sent to. This information is combined with data available to the LIS (usually extracted from a database
Database
A database is an organized collection of data for one or more purposes, usually in digital form. The data are typically organized to model relevant aspects of reality , in a way that supports processes requiring this information...
) to determine a final location. How this tracing is done then depends on the type of network.
In wireless networks, a range of technologies can be applied to location determination, the most basic of which uses the location of the radio transmitter as an approximation. The actual method applied is similar to the wiremap method, if a radio transmitter can be identified, then the location of the device can be given as the position of the transmitter with a region of uncertainty
Measurement uncertainty
In metrology, measurement uncertainty is a non-negative parameter characterizing the dispersion of the values attributed to a measured quantity. The uncertainty has a probabilistic basis and reflects incomplete knowledge of the quantity. All measurements are subject to uncertainty and a measured...
.
Architecture and Protocols
The IETFInternet Engineering Task Force
The Internet Engineering Task Force develops and promotes Internet standards, cooperating closely with the W3C and ISO/IEC standards bodies and dealing in particular with standards of the TCP/IP and Internet protocol suite...
has defined an architecture and protocols for acquiring location information from a LIS. A LIS in the immediate access network is automatically discovered and location information is retrieved using the HELD protocol. Location information can be retrieved directly—known as by value—or the LIS can generate a temporary URI
Úri
Úriis a village and commune in the comitatus of Pest in Hungary....
that can be used to provide location indirectly—known as a location URI.
The location information provided by a LIS primarily uses the GEOPRIV format (RFC 4119), an XML
XML
Extensible Markup Language is a set of rules for encoding documents in machine-readable form. It is defined in the XML 1.0 Specification produced by the W3C, and several other related specifications, all gratis open standards....
representation based on the presence
Presence information
In computer and telecommunications networks, presence information is a status indicator that conveys ability and willingness of a potential communication partner—for example a user--to communicate...
format defined in RFC 3863. RFC 4119 provides a container for both geodetic position and civic address information (now updated by RFC 5139) and also defines elements for expressing a user's privacy preferences.