Recommendation for provider - SIP/TLS?


We’re a current 8x8 customer but have encountered some limitations with that service, specifically re: encryption of the SIP traffic between our offices and 8x8. We intend to stand up an Asterisk/FreePBX box in-house and move our service to a provider who can provide SIP over TLS/SRTP. Hoping some of you here can provide some insight or recommendations based on our requirements and business size.

Our requirements:

*End-to-end encryption of SIP signaling and media traffic between this office and provider
*8 channels
*Needs to be achievable without use of an SBC. We do have a SIP-aware firewall at our network perimeter
*Provider should be experience in, or specialize in, secure SIP

We’re data network folks with limited voice experience, but have successfully implemented SIP/TLS/SRTP with a Lync endpoint in the environment in the past. We had some difficulty with that provider and ultimately determined the Lync solution was not viable for us. That experience is specifically why I mention that we’re looking for a provider who can implement TLS/SRTP with an Asterisk gateway.

Can anyone recommend a reasonably-priced SIP provider who can meet the above criteria? Anything else I should watch out for - have I made any false assumptions here?