More than one VP200 behind the same IP
Yes, you can have more than one VP200 behind the same IP. The way Sorenson handles this is by port-mapping the H.225 call-setup port (typically 1720) to different port numbers for each phone. They then publish those differently in the iTRS database.
Normally, your phone number would appear either without a port number, or with :1720 like this:
dig @neustar 2.1.2.1.5.5.5.1.2.3.1.itrs.us NAPTR +short
2.1.2.1.5.5.5.1.2.3.1.itrs.us. 900 IN NAPTR 10 1 "u" "E2U+h323" "!^(.*)$!h323:\\1@1.2.3.4!" .
Or like this:
dig @neustar 2.1.2.1.5.5.5.1.2.3.1.itrs.us NAPTR +short
2.1.2.1.5.5.5.1.2.3.1.itrs.us. 900 IN NAPTR 10 1 "u" "E2U+h323" "!^(.*)$!h323:\\1@1.2.3.4:1720!" .
If you have more than one phone behind the same IP address, you might see different port numbers listed in iTRS, like this:
dig @neustar 2.1.2.1.5.5.5.1.2.3.1.itrs.us NAPTR +short
2.1.2.1.5.5.5.1.2.3.1.itrs.us. 900 IN NAPTR 10 1 "u" "E2U+h323" "!^(.*)$!h323:\\1@1.2.3.4:3000!" .
dig @neustar 2.1.2.1.5.5.5.2.3.4.1.itrs.us NAPTR +short
2.1.2.1.5.5.5.1.2.3.1.itrs.us. 900 IN NAPTR 10 1 "u" "E2U+h323" "!^(.*)$!h323:\\1@1.2.3.4:3001!" .
For the above examples, @neustar would be the IP address of the Neustar Query Interface (QI), which can only be accessed if you are a VRS provider.
On your router, you would need to have it port-mapped for those TCP ports to each phone's port 1720.
To update the iTRS database, though, you're going to want to involve Sorenson, as only they can update it for you. It's probably for the best that you involve Sorenson to help you with the port forwarding anyway, it can be tricky to get right depending on your router.
Other providers do this differently. Purple and ZVRS, for example, use server routing and NAT traversal to avoid the need for port forwarding:
1. Purple points all of their P3 phones at the same Vidsoft H.323 gateway at 174.137.37.16.
- Multiple P3 phones can be behind the same customer home IP address.
- So long as all phones calling their numbers signal the destAddress phone number correctly, they can route the call to the correct phone.
- This means that VP100/DVC1000 and other older phones that can only dial by IP address cannot contact them.
- This also means that VP200s returning calls from their call history cannot contact them (as Sorenson has broken return-calls to only return the calls to the IP address that called them, and the VP200 does _not_ signal the phone number that called them when returning a call, so the Vidsoft gateway has no idea who to contact)
- Dial-around for "svrs.tv" does not work, as Sorenson CAs call back the IP address that called Sorenson for VRS service.
2. ZVRS gives all customers a unique "ZConnect" IP address. This address is an IP address in the Internet cloud that acts as a proxy for a specific phone. As each IP is unique, and all inbound and outbound calls from non-Z phones go through this IP, return calls and calls from older IP only phones should work every time.
- Multiple Z phones can be behind the same customer home IP address.
- VP100/DVC1000 and other legacy IP only phones _can_ call a ZVRS phone by this ZConnect IP.
- VP200 call history return calls _can_ call a ZVRS phone.
- Dial-around for "svrs.tv" works as expected
