SER/OpenSER and Asterisk VoIP serivce provider system

We are developing a Business/residential VoIP service. We will be targeting business. Our phone plans will include unlimited calling in the UK and international numbers, 4000 minute calling plans for a flat fee in UK, with single line and Centrex service with multiple line/extensions and international inbound numbers. We will also have other services like, IVR, Music on hold, Queuing, Hunt groups and more for our multi user customers. We want to give every Centrex customer, a reception desk interface for monitoring and transferring calls to internal extensions and external PSTN numbers. We would need NAT traversal and SIP proxy; you can use asterisk and SER to achieve that on two different servers. The setup that we are looking for should include the ability to configure new accounts from a web based interface, and online signup and management system for customers where they can configure and setup there own system including IVR, Queue, Hunt group, extensions, and also can view invoices. We would also require a comprehensive billing system integrated for different types of price plans and packages, and CDR management. We would like to be able to design and implement these packages and special offers like half price and free month packages on the web administration interface. Also the bills will be generated in PDF format and we will need the facility to change them on the fly which will reflect in the customer control panel. In the billing we will also need reseller partner facility where resellers can add/introduce customers and earn commission. All details will be provided in detail. This is phase 1, in phase 2 we will also be implementing high availability and web based white label reseller options. we would like you to be able to support it for the period or at least one year and train our developers during that time. Please quote for support separately. This installation will be a pure IP based solution. Origination and Termination will be provided via 3rd party providers using either SIP or IAX. We would need client support on both SIP and IAX. Deliverables: 1. A complete SER and Asterisk solution capable of handling any number of users (I understand the bandwidth and hardware limitations, we will consider your recommendations). 2. Billing module to handle toll calls and over minute usage. It should also be able to handle the prepaid calling cards and up front billing of the monthly phone packages. Credit card payment integration for call charges and monthly line rental. These payments will be processed automatically from this system on a preconfigured date of every month. Also ability to manually credit any account using the same facility done on both user and admin control panel website. Also we will not forget about the customers who can’t pay by credit card, so a manual method needs to be provided for them. 3. Automatic provisioning of new phone accounts based on the product they purchased. If they only purchased online and activation of the account as soon as payment is made. 4. Web interface for users to view call data records and account information 5. Calling card application with web provisioning and online recharge. Calling card numbers delivered via email. 6. Recording of voice greetings via a handset. 7. Retrieval of voice messages via handset, website and email. 8. Referral Reward Point system and reseller system To sum it all, we are looking for someone that can give us a total solution that will be ready to run and accept customer with an easy to use interface.