Literal Location vs. Location Reference


There are two obvious forms that the information provided by the device can take. It can either be the location information itself (the "literal" location) or it can be some form of reference information that tells the recipient where it can go to obtain the literal location information. The i2 architecture supports both concepts. Referring again to Figure 1.11, the IP device conveys the location information to the VoIP call server via the interface labeled V1. The call server passes the location information to the VPC over the interface labeled V2; it does this in part because of its need to be informed about how the call should be routed based on the provided location. The VPC is the entity that determines the correct routing information for the call server. If the literal location has been conveyed in these steps, the VPC already has what it needs to know to make a judgment on routing the call. However, if the location was conveyed as a reference, the VPC then goes to the system identified by that reference and retrieves the literal location. This occurs via the interface labeled V3. The ability for the VPC to request location directly via V3 is useful to obtain fresh updates of the caller's location throughout the call. Where the access network is a wireless WAN and, as in the case of cellular, the user may be mobile while making the call, PSAP/ALI is able to request periodic updates of the location. The VPC could not do this if it only had the initial literal location value rather than the reference, which permits a periodic re-query to the location information server (LIS).



IP Location
IP Location
ISBN: 0072263776
EAN: 2147483647
Year: 2004
Pages: 129

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