[Asterisk-Users] Alternative to FWD

[Joseph]

What are the alternatives to FWD with IAX2 registration capability.

FWD is great, but their IAX2 is not the priority and if it goes down it
takes days to restore it.
I want to use IAX2 protocol but the end point (Sipura unit) need to be
able to register over SIP behind firewall.
Line1 is registered with FWD
PSTN need to be registered with somebody else.

What are my alternatives? 

-- 
#Joseph