Patent ID: 8274964

Claim:
A method for routing calls in a cellular telecommunication system having at least one mobile switching center (MSC) using a routing table database to route calls over standard circuit trunks, comprising: adding packet core access trunks to the routing table database, wherein the packet core access trunks represent voice bearer paths through a packet core network; receiving a call for a called party number; performing digit analysis on the called party number and obtaining a list of candidate trunk groups from the routing table database, the list potentially including both circuit trunks and packet core access trunks; if the call is from another MSC: checking the trunk type of the call and checking to see if a routing bias for packet trunks or circuit trunks has been specified; if the routing bias is ‘packet’ and the list of candidate trunk groups includes packet core access trunks, pulling the packet core access trunks to the front of the candidate trunk group list and attempting to establish outgoing voice connection using the prioritized candidate trunk group list; if the routing bias is ‘circuit’ and the list of candidate trunk groups includes packet core access trunks, pushing the packet core access trunks to the end of the candidate trunk group list and attempting to establish outgoing voice connection using the prioritized candidate trunk group list; and if the routing bias is ‘blank’, attempting to establish outgoing voice connection using the obtained candidate trunk group list; if the call is from an originating mobile terminal: checking to see if the candidate trunk group list includes at least one packet core access trunk, and if so, performing special processing for packet voice support by checking to see if the call is compatible with packet core network and if system resources are available, if so, routing the call as a packet voice call, otherwise, removing the packet core access trunks from the list and routing the call using circuit trunks.