It presents an open source application for providing video, voice and messages to millions of users. It presents a perfect combination of following IMS architectural principles and support of key standardized interfaces. It is totally designed for the Cloud. Also by using specific design patterns, it is achieved to have a combination of significant cost-effectiveness and strong flexibility.
Architecture of Clearwater
Design of the Clearwater was focused on using it in the cloud and virtualized environments. It is not identical to the traditional IMS but it has some similarities. Bono nodes provide both WebRTC and SIP IMS Gm interface to clients by forming a horizontally flexible SIP edge proxy. Bono nodes are anchor points for the connection of the Clearwater and the client. Sprout nodes present a combination of authoritative routing proxy and SIP registrar which handle authentication of the client and ISC interface to the application server. As both nodes are transaction stateful proxies, passing all SIP headers transparently it makes Clearwater supporting the majority of SIP-related RFC. Diameter gateway, HSS cache, Ralf, Vellum, XDMS, Ellis with load balancing make a perfect combination of this application.
What does it do?
In basic it is all about SIP based messaging and video and voice control and communication. For example, it can be used in VoIP services. Actually, it does everything an IP Multimedia System should do. This includes something like WebRTC gateway, serving and interrogating CSCF (Call Session Control Function), incorporating Proxy CSCF and other. Fast deployment can be done on Amazon Web Services in just a couple of hours. After making it possible an appropriate on AWS you can use our own private cloud. Clearwater works easily with softphones such as Polycom Soundpoint, Sipdroid and Jitsi.
It offers video and voice calling service with features such as Call Barring, Call forwarding and Caller ID. If you are into more sophisticated services there are some additional elements needed for Clearwater. For example with the aid of external TAS as Metasphere Multimedia TAS you are able to support Hosted PBX with Clearwater.
For some typical user profile of Clearwater is less than 2US cents per subscriber per year. There may appear need of additional costs if you choose to use media Resource Functions in the Cloud.
Reliability and security
Clearwater follows common design patterns which lead to an easier approach to flexible web services. SIP communications here are separated into the untrusted zone (messages between Bono nodes and clients from outside system) and trusted zone (communication between Bono nodes, Sprout nodes and trusted applications). Different ports are used in order to isolate trusted zone by security groups and firewalls while untrusted zones are protected by standard SIP authentication.