[VoiceOps] SIP routing engine - growing pains

[Jay Hennigan]

Trying to pick the collective brain here!

Scenario:

We are a growing network service provider with ISP roots.  We got into 
VoIP by selling outsourced hosted PBX services.  Merged with a company 
doing early Asterisk deployment of hosted VoIP.

Now doing trunk replacement with Adtran TA9xx at customer premise.

PSTN connections are PRI trunks to a wholesale provider routed through 
ah Atlas 550 to feed our Asterisk and Cisco 5350 SIP gateways, SIP 
trunking and some offnet via outsources hosted PBX provider.  Recently 
added local ENUM database server feeding the 5350s as dial-peers got 
unwieldy.

Our ultimate goal is to migrate from the outsourced hosted provider to 
our own Broadsoft platform or equivalent but we're not yet at critical 
mass to make that financially viable.  We're presently peaking at about 
150 to 200 simultaneous calls busy hour through our own fabric plus 
about that on the hosted PBX provider offnet.

What I'm looking for:

SIP routing engine and/or softswitch but don't need feature server. 
Needs to do at a minimum:

* SIP routing based on destination number or pattern.
* Registrar for remote Adtran TA9xx at customer sites.
* Interface via SIP with 5350s for calls using PRI to PSTN.
* Fax compatibility T.38/G.711 passthrough.
* Support multiple SIP carriers inbound and outbound.
* CDR generation.
* Robust enough for solid performance - failover pair or load-balanced
* Ability to grow to handle ~1000 simultaneous calls

Nice to have:

* LCRE based on time of day or destination pattern.
* Geographic redundancy, located in multiple POPs.
* NAT traversal B2BUA type functionality
* IPv6 or at least a path to IPv6 functionality
* Transcoding

Suggestions and/or recommendations?

--
Jay Hennigan - CCIE #7880 - Network Engineering - jay at impulse.net
Impulse Internet Service  -  http://www.impulse.net/
Your local telephone and internet company - 805 884-6323 - WB6RDV