As already mentioned, in DWCP one node has a special role: the MGW. It serves not only as a gateway to external networks; it also has the responsibility for the complete IP address pool which should be used in the WMN. Therefore, if no default address pool should be used, the MGW has to be pre-configured with the desired IP address range. At first the MGW subdivides the IP address range into smaller disjoint gateway address pools. These address pools are continuous address ranges identified by an arbitrary length prefix. Thereby, DWCP’s protocol overhead is minimized and the external routing can be simplified in case the gateways announce responsibility for a pool via the external routing protocol. Next, the MGW assigns one of these gateway pools
to itself. All other mesh gateways can now request their gateway address pool from the MGW, which is assigned to them for a fixed lease time (Section III-F). Finally, as the MGW also
acts as a normal gateway, the MGW performs the same steps like a PGW that has received its gateway address pool. Another task of the MGW is to advertise itself to the WMN. Therefore, periodic MGW advertisements are disseminated network wide. They include the external and internal address of the MGW, the IP range and prefix, and a list of all known mesh gateways. With the help of these advertisements the following tasks can be performed: the detection of partition and merging, the detection of unavailability of the MGW, and the initial configuration of SGWs.
As already mentioned, in DWCP one node has a special role: the MGW. It serves not only as a gateway to external networks; it also has the responsibility for the complete IP address pool which should be used in the WMN. Therefore, if no default address pool should be used, the MGW has to be pre-configured with the desired IP address range. At first the MGW subdivides the IP address range into smaller disjoint gateway address pools. These address pools are continuous address ranges identified by an arbitrary length prefix. Thereby, DWCP’s protocol overhead is minimized and the external routing can be simplified in case the gateways announce responsibility for a pool via the external routing protocol. Next, the MGW assigns one of these gateway pools
to itself. All other mesh gateways can now request their gateway address pool from the MGW, which is assigned to them for a fixed lease time (Section III-F). Finally, as the MGW also
acts as a normal gateway, the MGW performs the same steps like a PGW that has received its gateway address pool. Another task of the MGW is to advertise itself to the WMN. Therefore, periodic MGW advertisements are disseminated network wide. They include the external and internal address of the MGW, the IP range and prefix, and a list of all known mesh gateways. With the help of these advertisements the following tasks can be performed: the detection of partition and merging, the detection of unavailability of the MGW, and the initial configuration of SGWs.
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