1. Directly to your static IP address via SIP URI. For example, firstname.lastname@example.org The instant the number ports, your PBX answers the calls just like it did on the loosing carrier (as long as you have inbound rules created). When configured correctly, this setup is practically indestructible.
SIP INVITE example:
220.127.116.11 SIP.LAX 2016/06/12
INVITE sip:email@example.com SIP/2.0
From: "James M." sip:+firstname.lastname@example.org;tag=as3bf610bb
CSeq: 102 INVITE
Many customers with 24/7 ops (finance, medical or travel) use two independent systems with DNS SRV. This feature allows you to use two separate redundant PBX systems and instantly reroute voice traffic. DNS SRV entries can return several IPs, by order of priority, on a specific port. For example, sip.domain.com SIP 5060 can have DNS SRV entries of: 18.104.22.168 and 22.214.171.124, two independent systems at different IPs. If you point your DID to a DNS SRV based hostname, our system will instantly detect failure on primary IP and will replace that entry with 2nd entry from your DNS SRV.
You can have more than 2 entries of course and more than 2 IPs associated with the hostname. Failure detection is nearly instant and our proxy will keep distributing calls to IPs that are live and respond. You only need to point to 1 hostname on our end. By managing DNS SRV on your end, you can have health checks and call distribution required.
2. To your SIP endpoint actively registered to DID Logic. Any IP PBX capable of SIP registration can be used to route your DID number. The SIP REGISTER method can be used on 3CX, FreeSwitch, Asterisk and many other office PBXes.
Registration string example:
3. Forwarded to PSTN. You can forward your DIDs to domestic or international phone numbers. This option can be used for backup, DR, and mobility purposes.