The DNS and the serving GPRS support node/mobility management
entity (SGSN) communicate by using a DNS protocol based on the User
Datagram Protocol (UDP).

On a complex network, the network topology is configured on the DNS
server. This ensures that the network topology data obtained by each
SGSN is consistent.

The main functions of the interface connected to the SGSN are as follows:

• The network topology is configured on the DNS server.
• The SGSN sends a request for domain name resolution to the DNS server.
• The DNS server sends the query result to the SGS

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