Since a PGW is pre-configured with the external address of the MGW it can instantly request a
gateway address pool from the MGW. The internal connection has not yet been configured and, by using the externalconnection the autoconfiguration protocol does not increase the load of the WMN. With its request each PGW sends a unique 46identifier (UID) generated from the medium access control(MAC) address of the internal interface and the startup time. The UID is later used for the election of a new MGW and in the case of a network merge. The MGW stores the UID of each
mesh gateway together with its external IP address to identify further requests and assigns the requesting mesh gateway a gateway address pool. Besides the requested gateway address pool the MGW sends also the addresses of the NTP and DNS servers that should be used by the mesh clients. If a message gets lost during the assignment, a three way handshake is used to ensure that no address pool will be blocked unnecessarily. After having received the gateway address pool, the PGW first splits its pool into smaller disjoint router address pools. Next, the mesh gateway assigns one of these router address pools to itself. All other router address pools are kept for
requesting mesh routers. Finally, the PGW configures its internal interface with the first IP address from its router address pool and starts a DHCP server on it. Requesting mesh routers
and clients can now allocate IP addresses by using DHCP.