Patent ID: 9294433
Filing Date: 2016-03-22
CPC Classification: H04L

Claim Text:
1. A method for operating a domain name system (DNS) in a Voice-over-Internet Protocol (VoIP) call routing system, the DNS including at least two DNS servers in a multi-master configuration that provides dynamic DNS call routing information for setup of a VoIP call, the method comprising, at a first master DNS server of the at least two DNS servers: updating DNS data records between the first master DNS server and a second master DNS server of the at least two DNS servers; monitoring for network isolation of the first master DNS server relative to at least one wide area network; entering an isolation mode in response to detecting network isolation of the first master DNS server of the at least two DNS servers, the isolation mode defining rules for a plurality of DNS zones; monitoring, while in the isolation mode, for network connectivity of the first master DNS server relative to the wide area network, wherein the steps of monitoring include attempting to access a plurality of remote websites; exiting the isolation mode in response to detecting network connectivity of the first master DNS server relative to the wide area network; updating, in response to exiting the isolation mode and to the rules for the plurality of DNS zones, DNS data records at the first master DNS server and for a first set of DNS zones using data from the second master DNS server of the least two DNS servers; at the first master DNS server, processing DNS update requests received in the first set of DNS zones; and at the second master DNS server, processing DNS update requests received in a second of the plurality of DNS zones.