User`s guide

PassFinder AP2520 VoIP Router/Gateway Operation Manual Version 1.10 / Mar. 2002
AddPac Technology Co., Ltd. -
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routing domain consists of one backbone area and several areas.
z Area: An area consists of several networks, and each area has a network
configuration diagram called the status database. All routers in the same
area have a same databases. The area can communicate with the
backbone area only through Area Boarder Router (ABR.) In most cases,
routers within the area have internal area paths, other area paths and
external routing paths. To remove a path, the operator needs to define
the area as a stub area. Then, only an internal area path will be available.
z Backbone Area: The backbone area connects areas each other, and its
value is always “Area 0.” Every OSPF routing domain has one backbone
area, and every area shall be connected to the backbone area.
However, if any area cannot be directly connected to the backbone area
due to network design, the area shall be connected to the backbone area
through the virtual link (a kind of OSPF tunnel.)