Sip trunk or Ip peering

Hi all,

i want to connect my server, to a VSP , and they do support SIP-trunks (ip-peering) or ping-trunk or …

they will provide a Connectivity to do a sip-ip-peering between my server & their system ( SBC)
IP peering or ping : is basically the “options” message coming from VSP to my server, and i should reply with 200OK
they have asked me ,to insert PPI or PAI header for any invite calls , in order to accept these invites…

here is my questions:

  1. do i need anything special configs to do this sip trunk or it will work ,just as when i create a context+dial plan in extensions.conf & then add the sip-registery to sip.conf?
    what i mean is i currently have sip-registery , accounts ,and will this configuration works for the sip trunk configuration?

  2. how do i tell the system to use a number from my assigned pool of number from the VSP ? , if inserted them in the extensions.conf using the same DIALPLAN will it works?

so basically ,is there any difference between siptrunk using registery-accounts & the Ip peering(ping= options messages followed by 200ok ) ?

Appreciate your time & support.