A trunk is a logical connection between the Mediation Server role and a PBX, PSTN gateway, or Internet Telephony Service Provider. The trunk settings apply to any gateway the site or pool is associated with, so if these settings vary across gateways, a new pool might be required for each unique set. Creating a new trunk configuration has the following options:
• Scope—A trunk can either be scoped so that it applies to entire Lync Server site or it can be restricted to only a specific Front End pool. A global trunk configuration also exists.
• Maximum early dialogs supported—This value is the number of forked responses the opposite end of the trunk can support in a single SIP INVITE that it sends to the Mediation Server.