Editing Local Access And Transport Area (section)

===Local interconnection region===
Canada does define '''local interconnection regions''' (LIR's), which determine where points of interconnection (POI) must be provided by [[Competitive local exchange carrier|competing local exchange]] and mobile carriers to provide [[local number portability]].<ref>{{Cite web|url=http://www.crtc.gc.ca/eng/archive/2007/dt2007-23.htm|title = Rogers Wireless Partnership Part VII application regarding the requirement for a central office code in each served exchange|date = 12 April 2007}}</ref> A Canadian LIR is geographically smaller than a US LATA, typically comparable in size to a small city's flat-rate local calling area or to an entire large [[regional municipality]]. In areas where a small-city [[Digital Multiplex System]] controls a group of [[remote switching centre]]s, one for each surrounding village, the local interconnect region normally includes each exchange in the city plus all downstream remotes of those exchanges.<ref>[http://www.localcallingguide.com/lca_listlir.php List of Canadian LIRs] on localcallingguide.com</ref> In a [[Toronto]]-sized city, the LIR will include only the city itself.

While the LIRs resemble local calling areas in geographic size, there are some key differences:
* LIR's normally do not include incumbent local [[independent telephone company]] exchanges in locations not opened to competition, where the independent numbers are currently not portable.
* LIR's do not cross provincial boundaries. [[Lloydminster]] has an LIR for each province, as does [[Ottawa]]-[[Hull, Quebec|Hull]].
* LIR's closely follow network topology, which often does not match a local flat-rate calling area as local calling is defined by arbitrary regulatory constructs.

Example: The tiny unincorporated village of [[Beebe Plain]], divided by the [[Quebec]]-[[Vermont]] border, is served by +1-819-876 [[Rock Island, Quebec]], Canada (a remote station controlled from [[Magog, Quebec|Magog]]) and +1-802-873 [[Derby Line, Vermont]], USA (a remote station controlled from [[St. Johnsbury, Vermont|St. Johnsbury]]). Magog and St. Johnsbury are both a long-distance call from anywhere in Beebe Plain, even though Canadian subscribers can place local calls to [[Sherbrooke]], US subscribers can locally call [[Newport (city), Vermont|Newport]] and an international call within the village is local. An LIR assignment which follows network topology places the Canadian remote station in Magog's LIR, not Sherbrooke's LIR.<ref>[http://www.localcallingguide.com/lca_exch.php?exch=172360 Rock Island QC] on localcallingguide.com</ref>