country code
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... hierarchical routing is the phone network, where
country codes, area codes, exchanges, and finally subscriber lines
are different levels in the hierarchy. In the phone network ...
... subscribers in the local area (l),
the other exchanges in the area code (e), the other area codes in the
local country code (a) and other country codes (c). Using this
notation, hierarchical routing ...
... the other exchanges in the area code (e), the other area codes in the
local country code (a) and other country codes (c). Using this
notation, hierarchical routing has space complexity O(l + e + a + c).
...
... ability to group subscribers into exchanges, area codes and country
codes. Further, such abstractions must provide useful information for
the ability to do routing. Some abstractions, such as the group ...